Oldsquaw 66 Marbled murrelet 84
White-winged scoter 72
Surf scoter 72
Black oystercatcher 65
Northern phalarope 62
Common murre 70
Totals 470
Table 5. _Oil Vulnerability Index for 123 species of birds of the
Aleutian Islands_ (Total Points--2,689).
OVI 1-20 OVI 21-40 OVI 41-60
80 species, rare Canada goose 34 Fulmar 57
or occasional Least sandpiper 34 Slender-billed shearwater 53
(one point each) 80 Arctic tern 32 Greater scaup 52
Common raven 21 Common goldeneye 48
Bufflehead 52
Harlequin duck 60
Bald eagle 58
Peregrine falcon 41
Ruddy turnstone 44
Rock sandpiper 59
Western sandpiper 47
Red phalarope 58
Parasitic jaeger 43
Glaucous-winged gull 56
Black-legged kittiwake 49
Totals 80 121 777
OVI 61-80 OVI 81-100
Fork-tailed storm-petrel 67 Pigeon guillemot 82
Leach's storm-petrel 63 Whiskered auklet 88
Pelagic cormorant 63
Red-faced cormorant 63
Black Brant 70
Emperor goose 70
Oldsquaw 66
Steller's eider 72
Common eider 68
King eider 70
White-winged scoter 72
Common scoter 72
Black oystercatcher 65
Red-legged kittiwake 66
Common murre 70
Thick-billed murre 70
Ancient murrelet 74
Parakeet auklet 80
Crested auklet 76
Least auklet 80
Horned puffin 72
Tufted puffin 72
Totals 1,541 170
We have used our OVI system to show the vulnerability of birds to oil,
but it seems likely that the vulnerability index could be applied on
a much broader scale to help make decisions in other areas of human
activity and resource development. The vulnerability index system
could be applied to terrestrial as well as aquatic species by adding
or subtracting impacting factors, as appropriate. Indexes relating the
impact of man upon each North American species could have broad uses in
the field of conservation. Population explosions, as well as declines,
might be predictable. Human activity could be better adjusted to favor
or depress wildlife populations, as appropriate.
We believe that this vulnerability index system has promise for aiding
in the decision-making processes upon which future bird conservation
will depend.
References
American Ornithologists' Union. 1957. Check-list of North American
birds. 5th ed. Lord Baltimore Press, Baltimore, Maryland.
Fay, F. H., and T. J. Cade. 1959. An ecological analysis of the
avifauna of St. Lawrence Island, Alaska. Univ. Calif. Publ. Zool.
63(2):73-150.
Gabrielson, J. N., and F. C. Lincoln. 1959. The birds of Alaska.
The Stackpole Company, Harrisburg, Pa., and Wildlife Management
Institute, Washington, D.C. 922 pp.
Gibson, D. D. 1970. Check-list of the birds of Alaska. Univ. of
Alaska, Fairbanks. 2 pp.
Isleib, M. E., and B. Kessel. 1973. Birds of the North Gulf
Coast-Prince William Sound region, Alaska. Univ. of Alaska Biol.
Pap. 14. 149 pp.
Kortright, F. H. 1942. The ducks, geese and swans of North America.
Wildlife Management Institute, Washington, D.C.
McHarg, I. L. 1969. Design with nature. Natural History Press,
Garden City, N. Y. 197 pp.
Murie, O. J. 1959. Fauna of the Aleutian Islands and Alaska
Peninsula. U.S. Fish Wildl. Serv., N. Am. Fauna 61:1-364.
Palmer, R. S. 1962. Handbook of North American birds. Vol. 1. Yale
University Press, New Haven, Conn. 567 pp.
Peterson, R. T., G. Montfort, and P. H. D. Hallom. 1967. A field
guide to the birds of Britain and Europe. Houghton Mifflin Co.,
New York.
Robbins, D. S., B. Bruun, and H. S. Zimm. 1966. Birds of North
America, a guide to field identification. Golden Press, New York.
Sanger, G. A. 1972. Preliminary standing stock and biomass
estimates of seabirds in the subarctic Pacific region. Pages
589-611 _in_ A. Y. Takenouti et al., eds. Biological oceanography
of the North Pacific Ocean. Idemitsy Shoten, Tokyo.
Sparrowe, R. D., and H. M. Wight. 1975. Setting priorities for the
endangered species program. Proc. N. Am. Wildl. Nat. Resourc.
Conf. 40:142-156.
Stout, G. D., P. Matthiessen, V. R. Clem, and R. S. Palmer. 1967.
The shorebirds of North America. Viking Press, New York. 270 pp.
U.S. Fish and Wildlife Service. 1974. Birds of the Aleutian Islands
National Wildlife Refuge. Washington, D.C.
U.S. Forest Service and Alaska Department of Fish and Game. 1970.
Birds of Southeast Alaska, a check-list. The agencies, Juneau,
Alaska. 12 pp.
PROGRAMS AND AUTHORITIES RELATED TO MARINE BIRD CONSERVATION
Programs and Authorities Related to Marine Bird Conservation in
Washington State
by
Ralph W. Larson
Washington Department of Game
600 North Capitol Way
Olympia, Washington 98504
Abstract
Seabirds are one of the most visible biological
components of ecosystems, and yet little is
known about them. They could readily be used
as an index of marine environmental quality if
adequate studies were conducted to determine
populations, habitat needs, and causes of
fluctuations in abundance. The lack of adequate
funding at the State level has precluded
necessary studies to make these determinations
and to provide habitat protection and
preservation.
The State of Washington has developed a funding
source for protection, preservation, and
enhancement of nongame wildlife, which includes
seabirds. The sale of personalized license
plates for vehicles is now providing some
funds for nongame wildlife management--funds
which should increase as the popularity of
the licensing program increases. Outdoor
Recreation Bonds are providing funding for
habitat preservation. Authorities provided
the Washington Game Department are adequate
to manage and protect seabird species. Other
State laws offer additional protection to their
habitat--specifically the Shoreline Management
Act of 1971 and the State Environmental Act.
It has been often stated that seabirds are one of the most visible
biological components of ecosystems, and yet little is known about
them. Most studies to date have been on fish, and because of their
recreational and commercial value, the concern for maintaining the
marine environment has been primarily a result of the concern for
maintaining the fishery resource. The visible knowledge of the fishery
resource, however, becomes an "after-the-fact" knowledge since the
status of the stocks relates to the value and amount of the fishery--a
fishery resulting from survival under the surface in the marine
environment that can be very secretive about its quality until it is
too late to do something about it. Seabirds, however, are visible
above the surface, in numbers that can reflect changes in the marine
environment that occur below the surface, since many depend on the
subsurface quality that reflects populations of fish.
Studies in Oregon have indicated that consumption of pelagic fish by
murres (_Uria_ spp.), cormorants (_Phalacrocorax_ spp.), storm-petrels
(_Oceanodroma_ spp.), and shearwaters (_Puffinus_ spp.) account
for about 22% of the annual production of various species of these
fish. A decline in this food source will reflect a decline in the
seabird population. Why then should it be necessary to use only fish
populations as an index of marine environmental quality, when seabirds
can more readily be observed and can reflect the same changes that
occur?
As a public wildlife agency, the Washington Department of Game is
often attempting to justify the value of seabirds, and sometimes that
is not easy. When fishermen complain that the seabirds are eating
all of the food of our mighty salmon, and hunters indicate little
compassion because the birds have no value to sport hunting, one has
to think a little to explain their value. However, rhinoceros auklets
_(Cerorhinca monocerata)_ do drive herring into ball-shaped schools,
which attracts salmon in search of food--which in turn provides a
signal to fishermen that salmon may soon be in the area. Explaining
value to the hunter is a bit more difficult, but anyone who has taken
the time to go out on our marine waters and observe the many species
of seabirds and watch them flying and feeding cannot help but be
fascinated by them. The flight of thousands of murres skimming over the
water surface and somehow managing not to dash headlong into a wave is
a fascinating sight.
We who are in fish and wildlife work have had to readjust our thinking
and values during recent years. Our primary programs and concerns for
many years were with the fish, birds, and animals that were of value
to fishermen and hunters. Species of wildlife that we now classify as
nongame received incidental benefit from programs related to game fish,
game birds, and game animals, but we did not do badly in maintaining
and enhancing these incidental wildlife species, mostly by indirection.
However, in the last few years our Department, at least, has taken on a
new responsibility and a new look as related to nongame wildlife.
Our first positive step in this direction was to develop a funding
source for nongame wildlife programs. Our funding attempt charted its
way through stormy waters, but finally ended up being voted on by
the citizens of the State. Our citizens passed Referendum 33, which
provided funds to the Department for nongame wildlife programs from the
sale of personalized license plates. Although the funds have not been
adequate, they are a step in the right direction and have permitted the
Department to engage in a modest program of research and management.
We have placed one person in charge of our program to do the planning
and programming so necessary for developing an effective, growing
program. During the 1st year of operation, we contracted studies on the
rhinoceros auklet, the tufted puffin _(Lunda cirrhata)_, and the black
oystercatcher _(Haematopus bachmani)_. These studies have provided a
basic knowledge of some of the problems facing these seabird species.
As funds increase, additional studies will be made to provide more
information on these birds and others.
During the 1975 legislative session we were successful in amending
the personalized license program to include automobiles other than
passenger cars--a step which should further enhance our funding. We
anticipate that funding will increase from the sale of these license
plates each year. They serve as their own advertisement, and as more
plates are sold, the exposure to the public increases. We anticipate
that within the next few years the funding should reach $150,000 per
year--a modest sum to be sure, but nevertheless adequate to establish a
viable program.
We have been involved in studies funded through other agencies that
involve seabirds. The principal reasons for the studies are not
seabirds, but they become an integral part of any analysis that must be
made of our saltwater environs. One such study involves a comprehensive
status survey of the marine shoreline fauna of Washington. The
Department of Ecology has provided the funding as a part of their
analysis of resources that may be adversely affected by oil spills and
economic development of our shorelines. This study will be the first
one designed to comprehensively identify wildlife species associated
with our shorelines and will determine the species, their status,
location, and habitat. This study will provide a basis for readily
identifying visually the results of oil spills and of the economic
development of critical habitat areas, and provide sound basic data for
use in combating destructive projects in the marine environment.
We are finding that you cannot separate functions of other governmental
agencies that deal with marine waters from seabird analysis. Pollution
responsibilities, shoreline management, coastal zone management, clam
dredging, channel dredging, erosion control, housing development,
industrial expansion, shipping port development--to name a few--all
must have some effect on our seabird species. Therefore, we must
concentrate on obtaining an adequate data base to insure the
perpetuation of these valuable marine species.
As I indicated earlier, the Department of Game has not had a special
program to manage seabirds in the past, but this should not indicate
that we have not assisted in maintaining the seabird resource. Our
basic land acquisition program designed for waterfowl enhancement has
benefited seabirds. We now own some 15,500 acres of lands, tideland,
and marshes bordering the marine waters (including our Skagit and
Nisqually holdings) which provide habitat and protection for many
seabirds. We also recently acquired 48 acres on Protection Island,
designed to protect the nesting area of the rhinoceros auklet. This
purchase was an excellent example of how combined efforts of several
groups accomplished a nearly impossible goal.
Protection Island had been subdivided for summer home development and
many lots had been sold. The developer, however, got caught in the
requirements of our Shoreline Management Act with his last subdivision.
The uproar caused due to the use of this subdivision by auklets created
an atmosphere that made subdivision a real conservation issue. The
outspoken critics of the project from the Audubon Society, Fish and
Wildlife Service, independent conservationists, and our Department
enlisted the aid of Nature Conservancy to negotiate for purchase
of this subdivision, and after lengthy negotiations the option was
obtained, and the Department purchased the land from the Nature
Conservancy with funds provided by the Interagency Committee for
Outdoor Recreation. The area now is destined to be a seabird sanctuary,
with limited public viewing and incidental recreation use. This
project is an excellent example of the power of cooperative efforts by
conservationists to protect a resource.
The State of Washington now has a reasonably good legislative base to
insure constructive programs for management of our seabird resource.
Our legislative authority lies in State statutes under Title 77. These
authorities first provide that the wild birds, wild animals, and game
fish of the State are the property of the State and that they shall be
preserved, protected, and perpetuated. Any regulations for taking shall
be designed so as to not "impair the supply thereof."
The commission also has the authority to classify wild birds. Seabirds,
other than hunted species, fall into the category of nongame birds.
We also have the authority to regulate the propagation and protection
of wild birds, develop rules and regulations for taking them (or to
prohibit taking them), and to create game reserves and closed areas
where necessary to protect various species. Our authorities also
include the obligation to enforce the laws, rules, and regulations
pertaining to the protection of all wild birds.
The Department may also acquire land for habitat and for sanctuaries
for nongame birds and may exchange lands for these purposes. We may
also enter into agreements with the Federal Government, persons,
and municipal subdivisions of the State for all matters relating to
propagation, protection, and conservation of all wild birds, and may
lease State lands for this purpose.
We believe our authorities are now totally adequate to satisfactorily
manage the State's marine bird resources.
In addition to our personalized license plate legislation, which
earmarks funds for nongame wildlife, other State laws and programs
assist in protection of this resource. One program that has assisted
materially in providing funds for habitat acquisition is a bond issue
passed by citizens of the State designed to acquire and develop
recreational land in the State for public use. Our Interagency
Committee for Outdoor Recreation provides the necessary mechanism for
funding of projects, using these bond monies to match Federal funds.
Although recreation is a key factor in obtaining funding, it is still
possible to acquire key habitat for wildlife and develop a people-use
program around the primary purpose for acquisition.
The purchase of a portion of Protection Island was accomplished by
use of these funds, as I indicated earlier, and we are now working
again with Nature Conservancy to acquire key bald eagle habitat on the
Skagit River in northwestern Washington. The bond issues total some $50
million, of which this Department receives about 15%. The State now
is in its third bond issue, and we hope the citizens will continue to
support this program.
One of the newer laws is the Shoreline Management Act of 1971. This act
provides for development of comprehensive shoreline management programs
designed to control the development of these areas to insure protection
of the public interest, while still recognizing and protecting private
property rights consistent with this public interest. These plans
must be developed with citizen involvement. Shoreline classification
generally falls into four categories--natural, conservancy, rural, and
urban. The natural classification can accomplish the most substantial
benefit for marine birds. Provisions are also made for protection of
"shorelines of statewide significance." Plans for these areas must give
preference to uses favoring the public and long-range goals. These
shorelines cover the areas between low and high tide levels on inland
waters and high water and the western boundary of the State on our
Pacific Ocean coast.
Our State Environmental Policy Act, which requires that environmental
impact statements be prepared for various programs and developments,
gives our Department an opportunity to insure that our valuable
wildlife resources are given consideration during the planning phase of
the proposed project.
The Department feels that our authorities at this time are adequate
to protect marine bird populations and their habitat. The one lacking
factor, as usual, is the funding for both adequate management programs
and habitat protection. Our marine habitat is rapidly being developed
for recreational homesites and public use which can eliminate key
habitat use. A greater public awareness of the needs of marine birds
can be a help in preventing destruction of their habitat; however,
money talks the loudest. The acquisition of these key habitats is the
most positive means of insuring their retention. We have no solution
at this time to the funding problem and only hope that someone smarter
than we are can provide an acceptable solution before all of our
efforts become too little and too late.
Programs and Authorities of the Province of British Columbia Related to
Marine Bird Conservation
by
W. T. Munro
British Columbia Fish and Wildlife Branch
300-1019 Wharf Street
Victoria, British Columbia, Canada V8W 2Z1
and
R. Wayne Campbell
British Columbia Provincial Museum
Victoria, British Columbia, Canada
Abstract
British Columbia Provincial agencies are given
authority for protecting marine birds and their
habitats by the Provincial Wildlife Act, the
Parks Act, and the Ecological Reserves Act. The
Provincial Museum Act accommodates research
on marine birds. The Fish and Wildlife branch
has protected over 30,000 ha of intertidal
estuarine habitat in the form of reserves and
has conducted limited inventories of birds
on the Queen Charlotte Islands and northern
mainland coast. The Provincial Museum has
conducted inventories and life-history studies
of marine birds and maintains a repository for
information on seabirds, including a catalog
of colonies. Pollution from oil and chemicals,
improper logging practices, and disturbance by
boating recreationists are the most apparent
threats to the well-being of birds. Additional
inventories and the determination of seasonal
distribution are among the information needed
to better protect the marine birds of British
Columbia.
Most marine-associated birds in Canada are covered by the Migratory
Birds Convention Act and are therefore federally protected. In British
Columbia additional protection is provided by the Provincial Wildlife
Act. Several other provincial acts provide authorities related to
seabirds. The Provincial Museum Act permits research related to natural
history; the Parks Act and Ecological Reserves Act provide for the
protection of habitat and prohibit harassment of wildlife within park
and reserve boundaries; and the Firearms Act permits the closure of
areas frequented by selected wildlife to the discharge of firearms. The
fact that several authorities for the protection and conservation of
marine birds are available does not mean that they have been used to
full advantage.
British Columbia's irregular shores provide thousands of kilometers
of coastline, much of which is used by marine birds for nesting
and wintering as well as during migration. Through legislation of
different types, some of the more ecologically important and unique
sites have been protected. Twelve "ecological reserves," which are
basically inviolate preserve areas, provide habitat for and protection
to a number of major breeding colonies. Over 30,000 ha of intertidal
estuarine habitat has been protected by the provincial Fish and
Wildlife Branch in the form of reserves. Less than half of the total
area is in Order-in-Council reserves (passed by the Provincial
Cabinet), which afford strong protection; the rest is in departmental
map reserves, which merely means other agencies must inform the branch
before they disturb them; they are hardly secure. Provincial Parks
Branch protects other areas used by marine birds by incorporating them
within parks.
Research and conservation of seabirds in British Columbia have not
been a high priority in the Fish and Wildlife Branch, basically
because seabirds are not consumed by people. Our primary interest
in seabirds has been in their role as a life support system for the
peregrine falcon _(Falco peregrinus)_. Most Fish and Wildlife Branch
reserves have been established to protect estuarine habitat for fishes,
waterfowl, and shorebirds rather than for true seabirds. That situation
is not likely to change in the near future unless additional funds
become available to the Branch. About the most we can expect to do is
designate key areas as sanctuaries or wildlife management reserves.
Under the folio and referral systems now operational among resource
agencies in British Columbia, we have the opportunity to advise other
disciplines against approving practices that would adversely affect
wildlife. By those methods we are attempting to protect critical
seabird habitat. It must be stressed, however, that we can only advise;
we cannot force other agencies to follow procedures we suggest.
The only significant work relating to seabirds in which the Fish and
Wildlife Branch is presently engaged involves inventory of specific
sites on the Queen Charlotte Islands and the northwest mainland coast.
Those areas are ones on which we expect to find seabird colonies and
where applications for logging are pending. To enable us to advise the
Forest Service on the wildlife values of those sites, we began field
work in the summer of 1975.
The Federal Government, in comparison to what it has done on the
east coast and in the north of Canada, has been negligent in its
support of seabird conservation on the west coast. By far the most
seabird research by a government agency in British Columbia has been
accomplished by the staff at the Provincial Museum in Victoria. In
the past, beginning in the 1940's, museum personnel (mainly C. J.
Guiguet) explored and inventoried seabird colonies along the British
Columbia coast. Most work then was exploratory, and little quantitative
information was gathered. More recently, precise counts have been
obtained of seabirds nesting in the Strait of Georgia, Juan de Fuca
Strait, the central west coast of Vancouver Island, the northern
mainland coast, and the east coast of the Queen Charlotte Islands. That
information, along with quantitative data gathered in the summer of
1975, will be used to update the "Catalogue of British Columbia Seabird
Colonies" published in 1961 by the museum.
The museum has a number of programs under way.
• A cooperative survey with Washington State of colonies of the
double-crested cormorant _(Phalacrocorax auritus)_ in the Pacific
Northwest. To limit disturbance, that survey is to be conducted at
5-year intervals beginning in the summer of 1975.
• A survey of all islands, whether or not they are supporting seabirds,
in the Strait of Georgia and Juan de Fuca Strait in 1980, to detect
changes in populations after 1974.
• Monitoring changes in seabird populations along the west coast of
Vancouver Island, gathering data for all islands there. Permanent
quadrats will be established on ecological reserves in the area to help
detect such changes. As a result of such quadrats having been set up in
1967 on Cleland Island and being re-examined in 1974, we can document a
significant decrease in Leach's storm-petrel _(Oceanodroma leucorhoa)_
and a corresponding increase in rhinoceros auklet _(Cerorhinca
monocerata)_.
• Mapping vegetation substrate as it relates to seabird populations on
selected islands in the Province.
• Investigating differences in eggshell thickness between eggs within
clutches of glaucous-winged gulls _(Larus glaucescens)_ near Victoria.
• A saturation banding program for cormorants (_Phalacrocorax
penicillatus_, _P. pelagicus_, and _P. auritus_) on south-coast
colonies.
• Continued banding of select colonies of glaucous-winged gulls which
began in the 1960's. Life tables, survivorship curves, and dispersal
patterns should result.
The museum also acts as a repository for information on seabirds in
British Columbia and maintains files on the history of seabird islands
as well as references to literature published on all seabirds in the
Province. The references include unpublished theses and reports. This
information is easily retrievable--not a small contribution in today's
paper-producing society.
Future programs planned by the Provincial Museum, in addition to the
continuance of some of those already mentioned, include a system of
monitoring colonies every 5 to 10 years, depending on the sensitivity
of the species involved, to detect changes in population numbers and
distribution. It is also hoped that the first complete provincial
census, with cooperation from Federal and provincial agencies,
naturalist groups, and the like, can be budgeted and arranged for
in the summer of 1980. That census could conceivably be expanded to
include the entire Pacific coast of North America.
Some research on the breeding biology of seabirds has been conducted
by universities, notably the University of British Columbia under
the guidance of R. H. Drent and M. Udvardy. We expect that graduates
returning to coastal universities will continue that work. The section
of government dealing with ecological reserves has just recently
received funding to permit field studies on reserves harboring marine
birds. J. B. Foster, Coordinator of Ecological Reserves, emphasizes
that research by other agencies is encouraged under permit on
ecological reserves.
There are a number of threats to seabirds in British Columbia. Along
with the chemical pollutants in their environment and food, logging,
and the specter of huge oil tankers plying the west coast, we are
greatly concerned by the potential threat of boating enthusiasts and
recreationists. Well-meaning but uninformed vacationers and boaters
stopping to visit or picnic at seabird islands can do serious damage
to nesting seabirds. The possibility of loss of habitat to seabirds
from people searching for island summer homes poses a threat, and
indeed some seabird islands have already been lost to speculators. With
increased leisure time and travel the potential of unintentionally
introducing predators, such as rats (_Rattus_ spp.) and snakes, to
seabird islands is great. Intentional or accidental introduction of
mammals, such as mink _(Mustella vison)_, rabbit (_Sylvilagus_ spp.),
fox (_Vulpes fulva)_, and raccoon _(Procyon lotor)_, to islands is
another serious threat to the future existence of seabird populations.
The recent unauthorized and apparently unsuccessful introduction of
mink on the Queen Charlotte Islands could have resulted in the eventual
devastation of seabird colonies there and on adjacent islands. The
destruction of habitat by logging near colonies on large islands and
complete logging on small offshore islands will no doubt adversely
affect some seabird populations. Competition between increasing
numbers of gulls (_Larus_ spp.) and certain species of seabirds (e.g.,
storm-petrels and cormorants) may result in reduced numbers of the
seabirds.
What types of programs are needed? About 80% of all known seabird
colonies in British Columbia have been investigated to date, and a
modest program to monitor changes has been established. We do, however,
require exploratory work along the west coast of the Queen Charlotte
Islands and northern mainland coast. We need to know more about the
breeding biology and reproductive potential of each of the species
nesting in the Province, as well as about their adaptability to
different habitats. Will some burrow-nesting alcids use man-made tubes
erected in otherwise marginal habitat? Can and should more man-made
habitat be created for cormorants that have been displaced from
ancestral breeding grounds?
Of immediate urgency is exploratory work involving seasonal
distribution, abundance, and flight lanes of pelagic seabirds along the
coast of British Columbia--especially the northern portion. We lack
the base-line data which could help influence routes of oil tankers to
lessen the potential danger of spills to marine birds. We know little
about the winter distribution of marine birds, especially alcids.
As a general rule, offshore islands of less than 100 ha should be
protected completely from logging, and the larger ones supporting major
seabird colonies should have some protection from development. We must
also consider the possibility of preserving some islands which may act
as buffer areas and provide potential alternate habitat to seabirds.
Another concern is the effect of commercial and sport fishing in the
Province on food supplies for seabirds, and what damage, if any,
gillnetting may have on diving seabirds. Perhaps we should discourage
fishing by nets in areas where large numbers of seabirds aggregate to
feed.
We also need to know more about the effects of chemical pollutants on
individual species and on their reproduction. Of paramount importance,
and one which biologists tend to neglect, is communication among all
disciplines interested in seabirds. For example, a comprehensive file
of the history of seabird colonies in British Columbia is established
at the Provincial Museum. It would be a waste of time and money to
duplicate that file and have three or four scattered across the
country. We would be better advised to tackle another phase of work yet
to be accomplished. Communication assures that seabirds benefit and are
not unduly harassed.
Annual meetings, both local and international, of persons interested in
marine birds should be arranged so that problems relating to seabirds
can be discussed. For example, populations of glaucous-winged gulls in
British Columbia have increased exponentially in the past 10 years. If
they are a threat to the existence of other seabirds (e.g., Leach's
storm-petrel, double-crested cormorants), should they be controlled,
and, if so, how? Such meetings would also help develop a pattern of
universal census methods and techniques that could be put to use along
the Pacific Coast to provide comparable data from different areas.
Finally, in today's world, natural resource agencies must operate
on limited funding. How can one convince administrators to divert a
significant portion of those funds to the investigation of species that
are widely regarded as having little social importance?
A detailed bibliography of seabirds of British Columbia is available
from either of us.
We thank D. F. Hatler, J. B. Foster, and A. L. Allen for comments on
the manuscript.
Petroleum Industry's Role in Marine Bird Conservation
by
Keith G. Hay
American Petroleum Institute
2101 L Street NW
Washington, D.C. 20037
Abstract
Despite improved safety practices, engineering,
and navigational skills, marine tanker
transportation will not be 100% accident
free. The industry seeks to mitigate wildlife
losses through improved technology, research
in the rehabilitation of species exposed to
oil, and the development of oil spill/wildlife
contingency plans.
Oil spills and marine birds not only constitute a deadly mix but have
proved to be one of our toughest environmental problems to solve. The
rehabilitation of these tragic victims is plagued with controversy,
emotion, apathy, and biological unknowns. The costs have been high
and the survival rates low. During the last 10 years, a few dedicated
people working here and in Europe have reversed this trend. They have,
in addition, taken steps to develop contingency plans and conducted
research to reduce seabird mortalities from oil spills. I present a
brief status report on their progress and the melange of problems
involved.
The unfortunate encounter between spilled oil and marine birds is
not new. It goes back at least to the turn of the century, when
coal-burning steamships and sailing clippers were replaced by
oil-fueled vessels. Since then thousands of marine birds have succumbed
to floating oil, especially during World Wars I and II (Blanks 1942)
and in recent spills here and off the coast of Europe (Clark 1969).
With the current and projected demands for energy in the United States
and with expanded tanker traffic and accelerated development of
offshore petroleum reserves, the oil-contaminated ("oiled") bird is not
going to go away. Periodically, this ugly problem will arise, despite
the efforts of the petroleum industry to improve its safety practices,
engineering, and navigational skills. Unfortunately, the problem is the
product of the inherent fallibility of man and his imperfect machines.
We cannot ignore the situation. We must here, as elsewhere, improve our
technology and mitigate the impact.
A study of more than 100 spills that occurred throughout the world
between 1960 and 1971 revealed that about 1 in 5 spills (20%) involved
50 or more birds (Ottway 1971). Nearshore spills have a far greater
effect on waterfowl than do spills occurring several miles or more
offshore.
In the 1967 _Torrey Canyon_ tanker spill, some 8,000 oiled birds were
rescued. About 6,000 were picked up alive in England and about 2,000 in
France, at a cost estimated at $160,000 (Clark 1969; Bourne 1970). Less
than 5% of those treated by British authorities survived for release
some months later. The survival rate of those rescued in France is
unknown.
In 1969 the Santa Barbara spill resulted in the treatment of 1,575
marine birds, of which 169 were eventually released. Many of those
released were found dead within a short time (Smail 1971).
In 1970 the tanker _Delian Apollon_ was responsible for a spill in
Tampa Bay, Florida. Thousands of seabirds were lost. No exact count
was taken, but hundreds of birds were cleaned and farmed out for
rehabilitation. Reports show that many of the birds were returned dead
within a few days (Smithsonian Institution 1971).
In 1971, when two tankers collided under the Golden Gate Bridge at the
mouth of San Francisco Bay, the resulting spill involved some 4,686
oiled birds taken to cleaning centers (Lassen 1972). Eight months
later the last of 200 survivors (less than 5%) were released at a cost
estimated at $900 per bird (Smith 1975).
The most vulnerable species involved in spills have been the oceanic
birds such as the alcids--murres (_Uria_ spp.), auks (_Pinguinus_
spp., _Alca_ spp.), puffins (_Fratercula_ spp., _Lunda_ spp.), and
guillemots (_Cepphus_ spp.). Other species less affected included
ruddy ducks _(Oxyura jamaicensis)_, scaup (_Aythya marila_, _A.
affinis_), scoters (_Melanitta_ spp.), mergansers (_Lophodytes_ spp.),
oldsquaws (_Clangula_ spp.), and goldeneyes (_Bucephala_ spp.). Grebes
(_Podiceps_ spp.), eiders (_Polysticta_ spp.), loons (_Gavia_ spp.),
and cormorants (_Phalacrocorax_ spp.) are also frequently involved.
Ruddy ducks and scaup are particularly vulnerable during winter on
large river systems with heavy oil transport traffic. Fortunately, none
of the above species have been reported in jeopardy as a result of
spills in American waters.
In Europe and South Africa, however, it is believed that oil pollution
is responsible for a steady decline in seabird colonies. For example,
in known oil-dumping areas in the Baltic Sea, where some mortality
of oldsquaws has been associated with surface oil, their population
has dropped to about one-tenth of the pre-World War II level (Bergman
1961). Other authors report that oil spills have reduced the number
of scoters in the Baltic and off southeast England (Atkinson-Willes
1963). The auk populations off the coast of England have been reported
to be substantially decreased by oil pollution (Parslow 1967). Tankers
traversing South Africa's Cape of Good Hope are said to be responsible
for the reduction of jackass penguins, _Spheniscus demersus_ (Rowan
1968). Oil pollution, especially sustained pollution, has thus been
cited as a limiting factor on certain seabird populations.
Estimates of seabird mortalities from an oil spill are imprecise; they
may differ by thousands of birds. It is believed that only a small
fraction of the birds killed in a spill wash up on the shore. Some
authors have even speculated that the death rate at sea could range
from 6 to 25 times the number washed ashore (Tanis and Mörzer-Bruyns
1968).
In contrast to terrestrial birds and semiaquatic species (e.g., ducks;
geese; coots, _Fulica_ spp.; or gulls, _Larus_ spp.), totally seaborne
species have a restricted reproductive potential. Many, such as the
alcids, do not breed until they are 3 or more years old, and lay only
one egg per year. Only one in five survives to go to sea.
Until about 5 years ago we knew little about seabirds. They are not
game species (they taste fishy) and thus do not constitute an important
economic resource. They have never been the subject of intensive
waterfowl management or research by either State or Federal governments.
During the last 5 years a small group of people here and in England
have been studying marine birds--their distribution, population status,
physiology, diseases, and husbandry in captivity. Four organizations
have primarily been involved: The American Petroleum Institute (API);
the Wildlife Rehabilitation Center at Upton, Massachusetts; England's
Advisory Committee on Oil Pollution of the Sea; and the International
Bird Rescue Research Center in Berkeley, California. They have
encountered many common biological and people problems, some of which I
discuss here.
Biological Problems
The recuperation record for oiled seabirds in the past has admittedly
been dismal. A few birds have been returned to nature, but only after a
long and costly period of care. In the process, semidomestication often
takes place. The percentage of cleaned birds that actually survive
after release is even smaller. One should not infer from this small
percentage that rehabilitated birds cannot readjust to life in the
wild. Several successful reintroductions have been documented. U.S.
Fish and Wildlife Service bands were returned from two western grebes
that were cleaned and released after the 1971 San Francisco spill. One
bird was picked up a year later near Treasure Island, California, and
the second after almost 2 years, in the State of Washington (Fletcher
1973).
Survival rates have zoomed with recent strides in cleaning technology
and husbandry. The International Bird Rescue Research Center reported
a survival rate of 41%, based on hundreds of birds and about 20
different species over a 2-year period (Smith 1975). In South Africa,
where powdered clay was used as a cleaning agent on jackass penguins,
nearly 50% survived, although exact percentages have not been published
(Edwards 1963; Holmes 1973). Rapid retrieval, the relatively small
groups of birds treated, and expert cleaning and husbandry techniques
are largely responsible for high success ratios. Rehabilitation success
is measured not only in terms of percent survival but also in terms of
median length of captivity and average cost per bird.
Rescued oiled birds arrive at cleaning centers under a wide range of
physical conditions. Before capture they may have spent hours or days
in water, during which their energy has been continuously drained. The
oil destroys the bird's protective insulation, and metabolic rate must
be increased to sustain body temperature. Constant preening also takes
energy. Food demands increase, but feeding attempts, especially for
diving birds, are thwarted by oil-fouled plumage. A bird may arrive
at the cleaning center under stress, chilled, exhausted, dehydrated,
starved, and ill from ingested oil. Cold weather accentuates these
conditions. Often such birds are jammed together with other species,
hauled long distances, and immediately put through a series of cleaning
processes that would leave even a healthy bird weak and in a state of
shock. One marvels at the stamina of the survivors.
In most past spills, every bird found was routinely cleaned regardless
of its condition. Instead of attempting to reclaim all birds, a
selective judgment should be made. If a bird's physical condition makes
its chances of survival nearly impossible, it should be humanely killed
(except for rare or endangered species). This would enable workers
to devote more time and care to birds having a reasonable chance at
survival.
Fletcher (1973) stated that many variables affect bird survival:
weather conditions, the type and amount of oil in and on the bird, the
species, the distance of the spill from the shore, the time lag from
initial fouling until initial treatment, the degree of stress a bird is
subjected to, the husbandry techniques used, the time of release (the
sooner released, the higher the apparent survival), the number of birds
being cared for (the fewer birds being handled, the higher the survival
rate), the quality of the facilities available, and the training and
experience of the people handling the birds.
Many of the above biological problems are under study here and in
Europe, including the following.
• The effect of ingested oil on the mucosal transport mechanism of
marine birds. To use seawater, birds must be able to transport sodium
ions through the gut and expel the excess salt through the nasal
passages. Oil can block the mucosal ion transport mechanism, resulting
in dehydration and eventual death.
• The development of a successful program of hormonal and electrolyte
therapy to restore osmotic balance and the functioning of the salt
glands in contaminated seabirds.
• Treatment and prevention of aspergillosis (fungus infection); septic
arthritis or "bumble-foot" (joint capsule infections); breast sores
(especially in seabirds confined on hard surfaces); eye lesions (caused
by ammonia fumes from unsanitary pens); dehydration and hypoglycemia;
lipid pneumonia; and bacterial infections.
• Treatment of stress after capture, including perfection of handling
and cleaning techniques, administration of proper steroids, crowding,
light, temperature, noise levels, and so on.
• Development of proper nutritional regimes for certain species and
feeding techniques to eliminate forced feeding.
• The establishment of criteria for confident recognition of terminal
pathological conditions in oiled birds.
• Determination of optimum density of confined birds to insure healthy
conditions and adequate room for preening.
• Determination of proper time and conditions for reintroduction of the
birds into their native habitat.
People Problems
Handling an over-responsive and emotional army of bird-cleaning
volunteers and training them to play constructive roles is a major
undertaking. Planning, cooperation, understanding, patience, and clear
direction must be developed. In the absence of these virtues, chaos can
and has prevailed.
The San Francisco Bay oil spill of 1971 was a classic example. There
was virtually no State or Federal coordination. Splinter groups of
volunteers established their own "treatment centers" and jealously
guarded their patients. Some actually absconded with their pet patients
to seek better care elsewhere. Long hours, fatigue, and frustrations
led to dissension and bitter quarrels. Antiestablishment sentiment was
rampant.
Instant experts on bird cleaning, avian medicine, and nutrition
appeared or developed overnight. Veterinarians volunteered their
services, but their knowledge of oiled-bird treatment was limited. A
wide variety of food (from canned dog food to live shrimp) was given
the birds. Forced feeding was routine. Medications and vitamins of all
kinds were also administered. Needless to say, the states of the art
in treating oiled birds and handling volunteers were both in their
infancy. For both, the success ratio was near zero.
To prevent such fruitless efforts and the frantic, unorganized response
that prevailed, a well-designed contingency plan for wildlife involved
in an oil spill is needed.
Contingency Planning
It is only prudent to take reasonable measures to prepare for
oiled-bird emergencies. This is especially true in regions where
bird concentrations and oil shipment traffic converge. Almost equal
attention must be devoted to handling volunteers as to handling birds.
Safety is a major consideration. The sharp beaks of birds can be very
dangerous.
A model State contingency plan should include the following:
• A list of State and Federal agencies to be alerted, including 24-h,
7-day-a-week telephone numbers, and names of individuals to contact.
• Clarification of the roles of State and Federal agencies under the
Regional Response Plan of the National Oil and Hazardous Substances
Pollution Contingency Plan.
• A list of State and Federal laws pertaining to possession of birds
and mammals.
• An updated roster should be maintained of team members, assignments,
and responsibilities for inland and marine spills, including discovery
and notification, record keeping, public information, containment and
counter-measures, wildlife protection, and cleanup, restoration and
evaluation of effects on the biota.
• A list of individuals or organizations that possess skills and
experience in treatment of oiled birds (locally and nationally).
• Location of emergency wildlife reception and treatment centers.
• A list of the necessary supplies, equipment, and holding facilities
for cleaning, treating, drying, and post-care operations. Such
information can be obtained from:
--California Department of Fish and Game, Oil and Hazardous
Materials Contingency Plan (July 1974)
--International Bird Rescue Research Center, Aquatic Park,
Berkeley, California 94710
--American Petroleum Institute, 2101 L Street, Northwest,
Washington, D.C. 20037
--Wildlife Rehabilitation Center, 84 Grove Street, Upton,
Massachusetts 01568
• An organizational plan which includes assignments of duties and
responsibilities for personnel manning a bird-cleaning center. In
addition to bird cleaning and husbandry, assignments must be made for
record keeping, internal communications, public relations, logistics
(supplies), security, sanitation, safety, and meals.
• A slide lecture or film to instruct volunteers in the correct
techniques for handling, cleaning, and post-care of oiled birds.
• A selected bibliography of key references on oiled-bird cleaning and
care.
• Appendices to the plan should include maps of the major coastal oil
terminals, bays, and estuarine areas with heavy oil transport traffic.
Map overlays would depict the location of resident species and the
migratory patterns, species composition, relative abundance, and winter
concentration areas of migrants. Additional overlays would locate
commercially important demersal seafood areas (e.g., oyster and abalone
beds, lobster and crabbing locales) and marine mammal habitats. Further
refinement of an atlas could include information on tides, prevailing
winds, ocean currents, and water mass movements to assist in predicting
the path of spilled oil.
What Has Been Accomplished
The petroleum industry, through the API, took prompt steps to mitigate
the problem after the first seabird mortalities were reported from
Santa Barbara in 1969. They commissioned a young aviculturist, Philip
Stanton, who has extensive experience working with wild waterfowl, to
start a research program on cleaning and caring for oiled birds. At
his Wildlife Rehabilitation Center at Upton, Massachusetts. Stanton,
with the help of API, has been conducting research on oiled birds
for 7 years. He is also an assistant professor of biology at nearby
Framingham State College. Stanton's studies (unpublished) include
investigations on food shape and color preferences in wild ducks, the
effects of lengthened photoperiods on breeding of arctic geese, and
the effects of diets of varying protein concentrations on growth and
development of the common eider duck.
As a result of his research on cleaning techniques and agents,
Stanton has recommended a nontoxic liquid cleaner called Polycomplex
A-11. Although not perfect, it is one of several cleaning agents
being successfully used today. He has authored a "how to" guide
for oiled-bird treatment entitled "Operation Rescue" and prepared
a companion bibliography (Stanton 1972). These booklets have been
distributed throughout the United States to State and Federal agencies
and conservation organizations. He has provided consulting services at
numerous spills and has worked to establish oiled-wildlife treatment
centers in coastal States.
Since 1972 the API has sponsored an avian physiology study at the
University of California at Santa Barbara. Under the direction of W. N.
Holmes, the studies are directed at the effects of ingested crude oil
and petroleum products on marine birds. Holmes has revealed that small
quantities of crude oil introduced into the gut of a saltwater-adapted
bird can affect the mucosal transport and extra-renal excretory
mechanisms, resulting in acute dehydration and eventual death. Dr.
Holmes is also examining the effects of the various distillation
fractions derived from crude oil and the long-term effects of ingested
oil in mature birds. Incidentally, Alaska North Slope oil was found to
be almost innocuous when administered to ducklings in amounts similar
to the effective doses of other oils (Holmes and Cronshaw 1975).
Refined products (diesel oil, No. 2 fuel oil, and Bunker "C") are known
to be more toxic than crude oil. For example, the relatively small
spills of Bunker "C" at Tampa, Florida, in 1970 and in San Francisco
in 1971 caused approximate mortalities of 90 and 20 birds per ton of
spilled product, respectively. The crude oil spills of the _Torrey
Canyon_ and at Santa Barbara, however, resulted in mortalities of only
0.5 and 0.6 bird per ton of oil (Clark 1973).
Dr. Holmes is now testing measured amounts of the above refined oils
on adult birds. He is determining the degree of dehydration incurred,
the resulting pathological changes, and the replacement (hormonal and
electrolyte) therapy necessary to rehabilitate the birds.
It is obviously important to keep as many birds away from an oil
slick as possible. This was the objective of an API contract with the
Av-Alarm Corporation of Santa Maria, California. Their objective was to
determine the feasibility of repelling aquatic birds from an area by
using an acoustical jamming device as the stimulus.
The flocking instinct in birds provides mutual protection through their
almost constant communication with one another. When this (audio)
communication is prevented by jamming with high-frequency sounds,
the birds immediately leave the area to seek relief. This harmless
technique has been used successfully for years to repel agricultural
pest birds.
The Av-Alarm device was tested on waterfowl at the Grizzly Island Game
Refuge some 48 km north of San Francisco Bay and in the bay itself
over a 2-year period (1972-73). Using a single, fixed-location system
covering a three-quarter square mile (1.21 km²) area Crummett (1973)
repelled 82% of the ducks and 92% of the shorebirds on the Refuge. The
intrepid coot, however, was found to be relatively indifferent to the
sounds. Immediately upon activation, there was a sudden drop in the
bird count, which was followed by a continual decline in numbers.
In tests of the device from a cruising boat in ocean and bay waters,
the degree of effectiveness varied by species. Ducks were repelled
100%; pelicans (_Pelecanus_ spp.) 92%; great egrets _(Casmerodius
albus)_ 85%; gulls 42%; cormorants 75%; shearwaters (_Adamastor_ spp.)
29%; and murres, 51%.
Grebes and murres dived away from the stimulus, then surfaced and dived
again if the threat was still present. To prevent driving the diving
species deeper into the center of a slick, investigators recommended
that buoyed repelling equipment be placed within the spill area. When
the alarm system was used in conjunction with the occasional firing
of a rocket or shellcracker, an even greater percentage of birds was
repelled.
The International Bird Rescue Research Center, a nonprofit corporation
in Berkeley, California, was an outgrowth of the Richmond Bird Care
Center that played an active role in the 1971 San Francisco Bay spill.
Since that time, a small group of individuals has continued research on
bird-cleaning techniques, testing cleaning agents, perfecting husbandry
methods, and alleviating stress. Their 41% survival rate speaks for
itself. A paper describing their work is being presented at this
conference (Smith 1975).
Under a grant from the API, the center is currently evaluating various
cleaning agents, and testing the pressurized jet versus serial baths
and the re-establishment of feather waterproofing. The center is also
perfecting an audio-visual slide presentation that will illustrate
how to select the proper cleaning agent, together with the latest
bird-cleaning and care procedures.
About 5 years ago, England's Advisory Committee on Oil Pollution of the
Sea established a research unit in the Department of Zoology at the
University of Newcastle-Upon-Tyne. It was funded by a grant from the
Royal Society for Prevention of Cruelty to Animals, the Royal Society
for the Preservation of Birds, the World Wildlife Fund Seabird Appeal,
and the British Institute of Petroleum.
Their efforts have also led to high survival rates. Focusing primarily
on the efficiency of various detergents, they have found that the
loss of waterproofing is largely due to soap and oil residues and
the disturbance of the feather structure in the cleaning process.
Consequently, they have devoted their efforts to selecting detergents
that can be completely removed with a minimum disturbance of plumage
(Seabird Research Unit 1971).
In May 1974, the API in cooperation with the U.S. Fish and Wildlife
Service convened a seminar on Oil Spill Wildlife Response Planning.
The 2-day workshop was held at the Patuxent Wildlife Research Center
at Laurel, Maryland. Some 70 State and Federal government personnel in
charge of oil spill response plans involving wildlife participated.
The program addressed itself to fish and wildlife considerations
and the role of regional response teams under the National Oil and
Hazardous Substances Pollution Contingency Plan. The actions of State
wildlife departments, U.S. Fish and Wildlife Service, Environmental
Protection Agency, U.S. Coast Guard, and the oil industry in handling
spills involving wildlife were examined. The latest oil spill cleanup
technology was reviewed, and the workshop ended with demonstrations of
the cleaning of oiled waterfowl. Similar seminars were planned for the
Gulf of Mexico and the West Coast.
It was obvious from this seminar that the most comprehensive
wildlife oil spill contingency plan had been developed by the State
of California. Copies of this plan (Oil and Hazardous Materials
Contingency Plan, California Department of Fish and Game, July 1974)
were later distributed to all coastal States as a prototype or model
plan by API.
The U.S. Fish and Wildlife Service has been conducting experiments on
various bird-cleaning agents and techniques at its Migratory Bird
and Habitat Research Laboratory near Laurel, Maryland. The Fish and
Wildlife Service is also working with the API in developing information
on migratory patterns and winter waterfowl concentration areas on
the East Coast as they relate to petroleum transport traffic and oil
terminals.
In Canada, the Petroleum Association for Conservation of the Canadian
Environment (PACCE) employed the services of a consulting firm to make
a comprehensive review of dispersal and rehabilitation of waterfowl
associated with oil spills. The resulting PACCE report (LGL Ltd. 1974)
codified what was known about the problem, identified research needs,
and developed effective wildlife oil-spill contingency plans for
critical areas on Canada's east and west coasts, the Great Lakes, and
the Arctic.
The Florida Game and Fresh Water Fish Commission has initiated a
program for the rehabilitation and treatment of oiled birds. It is
being organized by veterinarian Harold F. Albers of St. Petersburg.
He is working in cooperation with the Florida Associated Marine
Institutes, the Shell Oil Company, Clean Gulf Associates, and the API.
The Standard Oil Company of California provided a grant to James
Naviaux of Pleasant Hill, California, to develop bird-cleaning
technology, including the testing of various cleaners. Dr. Naviaux
had treated birds from the 1971 San Francisco spill. A publication
on the after-care of oil-covered birds (Naviaux 1972) resulted from
the collaboration with Alan Pittman, research chemist of the U.S.
Department of Agriculture's Western Research Laboratory.
In 1971, the API in cooperation with the National Wildlife Federation
(NWF) initiated an NWF/API Fellowship program. One of the first grants
under this program was to Charles W. Kirkpatrick, Professor of Wildlife
Management at Purdue University. He and assistants studied for 4 years
the nesting ecology and productivity of the emperor goose _(Philacte
canagica)_ in the Igiak Bay area of the Yukon Delta in Alaska
(Eisenhauer and Kirkpatrick 1977).
An extensive program of marine bird research was initiated on the North
Slope of Alaska by the Atlantic Richfield Company in 1969. It has
been continued ever since and includes the acquisition of extensive
base-line data on all waterfowl, including June surveys of breeding
pair counts and August surveys for brood counts. The results of these
surveys for 1969-73 are presented by Gavin (1975).
Base-line data on marine birds of the Gulf of Alaska are currently
being collected and compiled through grants to various universities
and institutions by the American petroleum industry. These data will
constitute elements of a report on the environmental status of the Gulf
of Alaska. Such information is essential prior to development of the
Gulf's offshore petroleum resources.
Marine Mammals
Most sea mammals are relatively resistant to oil slicks and tend to
avoid contaminated waters. As a result, little research has been
conducted on cleaning and treatment techniques except for experiments
on live beavers and on the carcasses and pelts of sea otters and
beavers.
No sea otter or seal has ever been oiled and subsequently cleaned in an
oil spill situation. It is possible, however, that a spill could have
significant adverse effects on sea otters and fur seals, especially at
a rookery during the pupping season. These animals depend on an air
blanket trapped in their dense underfur for warmth and buoyancy. Any
form of pollutant, especially oil, could penetrate the outer guard
hairs and underfur and allow water to reach the skin, with disastrous
effects.
Seals and otters are powerful animals, and the larger males and females
can be quite aggressive and dangerous. Only professional wildlife
specialists and consulting veterinarians should be permitted to handle
and treat them. A guide to cleaning and care of oiled sea otters can be
found in the California Oil and Hazardous Materials Contingency Plan.
Conclusions
This status report has revealed that substantial efforts and progress
have been made in oiled-wildlife research. New techniques being
developed are leading to higher survival rates. Preventive measures
are being devised to keep birds from entering a spill area. Wild life
contingency plans are being developed and materials to handle future
emergencies are being stockpiled. Basic research is being continued on
the difficult problems inherent in achieving high survival levels and a
rapid return to the wild, at a reasonable cost.
Much more must be done, but these pioneering efforts both within and
outside of industry reflect a difficult problem yielding to the time
and attention of dedicated men and women.
References
Advisory Committee on Oil Pollution of the Sea. 1972. Research unit
on the rehabilitation of oiled seabirds. Committee, Dep. Zool.,
Univ. of Newcastle-Upon-Tyne, England, Annu. Rep. 2. 33 pp.
Atkinson-Willes, C. 1963. Wildfowl in Great Britain. Nat. Conserv.
Monogr. 3. 368 pp.
Bergman, G. 1961. The migrating populations of the long-tailed duck
_(Clangula hyemalis)_ and the common scoter _(Melanitta nigra)_
in the spring, 1960. Suomen Riista 14:69-74.
Blanks, D. W. 1942. Birds in the war zone. Gull 24(4):11.
Bourne, W. R. P. 1970. Special review--after the _Torrey Canyon_
disaster. Ibis 112(1):124.
Clark, R. B. 1969. Oil pollution and the conservation of seabirds.
Proc. Int. Conf. on Oil Pollut. of the Sea 1968:76-112.
Clark, R. B. 1973. Impact of chronic and acute oil pollution of
seabirds. Page 634 _in_ Background papers for a workshop on
inputs, fates and effects of petroleum in the marine environment,
Vol. 11. Ocean Board National Academy of Science, Washington, D.C.
Crummett, J. G. 1973. Bird dispersal techniques for use in oil
spills. Final report. American Petroleum Institute, Washington,
D.C.
Edwards, R. A. 1963. Treatment of washed up penguins. Bokmakierie
15(1):8.
Eisenhauer, D. I., and C. M. Kirkpatrick. 1977. Ecology of the
emperor goose in Alaska. Wildl. Monogr. 57. 62 pp.
Fletcher, A. 1973. Why save oiled birds? University of California,
College of Forestry, Berkeley. 26 pp. (Unpublished report)
Gavin, A. 1975. Wildlife of the North Slope, a five year study,
1969-73. Atlantic Richfield Co., Anchorage, Alaska. 63 pp.
Holmes, M. 1973. Oil and penguins don't mix. Natl. Geogr. Mag.
143(3):384-397.
Holmes, W. N., and J. Cronshaw. 1975. Final progress report on
studies completed, 1972-75, on the effects of petroleum on marine
birds. American Petroleum Institute, Washington, D.C. 77 pp.
(Unpublished report)
LGL Limited. 1974. Review of current knowledge on reducing bird
mortalities associated with oil spills. Petroleum Association for
Conservation of the Canadian Environment Rep. 75-4. 50 pp.
Lassen, R. W. 1972. Waterbirds and the San Francisco oil spill.
Proc. Cal-Nev Wildl. 1972:20-24.
Naviaux, J. L. 1972. Aftercare of oil covered birds. National
Wildlife Health Foundation, Pleasant Hill, Calif. 52 pp.
Ottway, S. M. 1971. A review of world oil spillages, 1960-1971. Oil
Pollut. Res. Unit, Orielton Field Centre, Pembroke, Wales.
Parslow, J. L. F. 1967. Changes in status among breeding birds in
Britain and Ireland. Br. Birds 60:2-47, 97-122, 177-202.
Rowan, M. K. 1968. Oiling of marine birds in South Africa. Pages
121-124 _in_ Proc. Int. Conf. on Oil Pollut. of the Sea.
Seabird Research Unit. 1972. Advisory Committee on Oil Pollution of
the Sea Research Unit on the Rehabilitation of Oiled Seabirds.
Second annual report. Dep. Zool., Univ. of Newcastle-Upon-Tyne,
England. 33 pp.
Smail, John. 1971. The oil spill in retrospect. Point Reyes Bird
Observatory News 18:1-2.
Smith, D.C. 1975. Rehabilitating oiled aquatic birds. Pages 241-247
_in_ Proc. 1975 Conf. Prevention and Control of Oil Pollution.
Smithsonian Institution. 1971. Annual report of the Center for
Short-lived Phenomena, 1970. Cambridge, Massachusetts.
Stanton, P. B. 1972. Operation rescue. American Petroleum
Institute, Washington, D.C. 32 pp.
Tanis, J. J. C., and M. F. Mörzer-Bruyns. 1968. The impact of
oil-pollution on seabirds in Europe. Proc. Int. Conf. on Oil
Pollut. of the Sea. 1968:67-76.
CONSERVATION OF MARINE BIRDS IN OTHER LANDS
Conservation of Marine Birds in New Zealand
by
Gordon R. Williams
New Zealand Wildlife Service
Department of Internal Affairs
Wellington, New Zealand
Abstract
Marine species (pelagic birds and those of
exposed coasts) make up about 48% of New
Zealand's native avifauna, excluding stragglers
and antarctic species. The biological history
that has led to the present status of marine
birds in this archipelago of some 700 islands
is outlined, methods of conservation are
briefly described, and some illustrative case
histories of management programs are given. In
spite of the major environmental changes that
have occurred in New Zealand during 200 years
of European occupation, only one marine species
has become extinct, although five such endemic
species are currently regarded as threatened
as are a few subspecies of widely distributed
forms.
New Zealand, which lies some 2,000 km southeast of Australia, has
been a changing archipelago for many millions of years. It has been
separated from any major landmass (first, Gondwanaland and later,
Australia) for at least 80 million years.
Before the arrival of man, probably between 1,000 and 1,500 years ago,
New Zealand was free of any land mammals except two species of bats,
and there were few avian predators. These, among a number of other
biological peculiarities, reflect the archipelago's considerable and
long-standing isolation.
There are nearly 700 islands 0.5 ha or more in area in the New Zealand
region; and, if North, South, and Stewart islands are regarded
collectively as the mainland, about 650 of these islands lie within
50 km of the coast and 30 beyond that limit, to about 850 km offshore
(Atkinson and Bell 1973). The archipelago extends from about 30° to
52°S lat. (over a distance of about 2,400 km)--that is, from the
subtropical to the subAntarctic--and from about 166° to 176°W long.
(Fig. 1).
Pelagic and coastal birds must obviously be an important part of the
avifauna and, in fact, aside from stragglers, antarctic species, and
established introduced species, they make up about 48% of the 173 in
the New Zealand Checklist (Kinsky 1970). Of the 83 species I have
regarded as marine, 48 (28%) are pelagic and 35 (20%) shorebirds of
exposed coasts. Ten of the 48 pelagics (21%) and 12 (34%) of the 35
shorebirds are endemic.
More than a thousand years of occupation by Polynesian man with his
commensal Polynesian rats _(Rattus exulans)_ and a peculiar breed
of domesticated and feral dog (now extinct), did little damage to
pelagic and open coast species, even though many, if not most, were
used as food--especially the petrels, and particularly those belonging
to the genera _Puffinus_, _Procellaria_, and _Pterodroma_. However,
the Europeans, who arrived about 200 years ago, brought with them a
menagerie of mammals and birds, and 33 species of each have become
established and are now feral (Gibb and Flux 1973; Williams 1973). They
also put into practice, on a large scale, European methods of land use
that had unfortunate effects on almost the entire native avifauna.
Although terrestrial, freshwater, and estuarine species suffered most,
marine species suffered also. However, reduction in numbers and range
rather than extinction was the rule, except locally.
Apart from habitat destruction by man and the various mammalian
browsers and grazers, the most inimical agents have been black rats
_(Rattus rattus)_, Norway rats _(R. norvegicus)_, feral cats, and feral
pigs. One would expect the inhospitality or inaccessibility of an
island to be a marine species' best protection, and so it has generally
proved-the greatest losses have occurred on the two major mainland
islands (North Island and South Island). Bourne (1967) suggested that
Polynesians in pre-European times may have caused the extinction of
numerous petrels in the Chatham Islands. There are still a few islands
on which no exotic mammals occur, but modern transport, allied with
human curiosity and cupidity, are stripping all but the most wild and
remote of these of the protection against invasion they have had so
far. Cruises by nature-hungry but sometimes environmentally illiterate
tourists are beginning to be a local problem.
[Illustration: Fig. 1. New Zealand and its main offshore and outlying
islands (from Atkinson and Bell 1973).]
The matter of conservation of marine species in New Zealand has
stemmed mainly from the recognition of the value of certain islands as
refuges for whole ecosystems, as convenient areas for study, and as
arks for the rescue of the threatened species that can be successfully
established on them--an often highly hazardous and uncomfortable
procedure for men as well as birds.
Conservation Measures
By statute, all feral species of birds in New Zealand are automatically
protected unless specifically legislated for otherwise. (About
50 of our grand total of 285 species have been so legislated
for.) One fortunate consequence of this provision is that all new
arrivals--vagrants or new discoveries--are also fully protected. The
legislation also states that it is illegal to have in one's possession
the nests, eggs, feathers, skins, or bones of any fully protected
species unless one has been issued a permit for this purpose. This
restriction may apply to institutions as well as to persons.
After this good start and the setting aside of conservation reserves of
various kinds, active conservation measures depend on making careful
and comprehensive surveys of the species and its ecosystem--often none
too easy a task in the New Zealand region because of the rough seas,
the relative inaccessibility of many of the important islands and their
ruggedness, and the near-impenetrability of some of the vegetation
types they support. Having decided that positive action is necessary,
the next step is to use all available media to inform the public (local
as well as national, if the island is inhabited) of the situation and
the proposals for remedying it. As in most other countries, uninformed
emotionalism is one of the most pervasive and serious obstacles to
effective conservation because of the political pressure it can
generate.
Apart from formal ecological studies, the New Zealand Wildlife Service
uses three main methods to support threatened species (other than the
attempts we are making to breed certain freshwater and terrestrial
species in captivity):
• The translocation and founding of new colonies in promising or
unmodified habitat. Such habitats are not common in New Zealand because
of the ubiquity of the introduced mammalian browsers, grazers, and
predators (Williams 1977).
• The destruction, or at least the reduction, of such browsers,
grazers, and predators by physical, chemical, or biological methods, or
combinations of these.
• The exertion of social influences to promote changes in methods
of land use or in traditional harvest for food (the latter can be
particularly important as far as the Polynesian [Maori] population is
concerned, as nowadays the taking of birds for food is predominantly a
cultural rather than an economic matter).
Translocation has been a valuable technique for increasing the numbers
and ranges of a few threatened terrestrial species. The very nature of
most marine species, however, limits its application as far as they
are concerned. Nevertheless, we have considered it worth trying for
one nonmigrant wader; and no doubt it could be tried under similar
circumstances elsewhere.
Convincing local experiences have shown that predator or competitor
destruction is likely to be practical only on small, not-too-rugged
islands, usually no larger than about 500 ha. However, special
circumstances have prompted us to attempt destruction, or at least
control, on much larger and more difficult islands. It is implicit that
the predators or competitors are exotic, not indigenous. Recently, on
those rare islands that are inhabited but still free of either black
or Norway rats, we have set up permanent bait stations (at which
sodium fluoroacetate--"1080"--is used as the poison) on wharves and
jetties in the hope that such a precaution will, with the addition of
a propaganda campaign calling for the regular fumigation of visiting
vessels, prolong the charmed lives that these fortunate islands have so
far enjoyed. It goes without saying that we ask that the greatest care
be taken when expeditions land stores on uninhabited, rat-free islands
which, if by "rat-free" we mean also free of _R. exulans_, are even
rarer in our seas.
The sociolegal approach is effective only when ecosystems or
communities have not been seriously modified, otherwise it is no
substitute for either of the other two measures discussed.
Some Case Histories
Translocation
Last century, an endemic monotypic genus of wader--the New Zealand
shore plover _(Thinornis novaeseelandiae)_--was widespread and
occasionally very common around the coasts of the North and South
islands and the Chatham Islands. As a result of European settlement
and the accompanying predation by feral cats and rats, the species now
occurs only on South East Island in the Chatham group (860 km east of
the mainland), where it at present seems safe, since there are no rats
on the island and it is now a reserve. However, the population numbers
only about 120 individuals. Because calamities can always occur (for
example, ship rats recently reached shore on three important islets off
the southwest coast of Stewart Island), the Wildlife Service is anxious
to spread the shore plover to other suitable islands, if they can be
found. The species is not a migrant and is rather sedentary. The first
translocation attempts failed, probably because mainly adult birds were
used, and we are now continuing our studies of the species with the
thought in mind, among others, that success may come if young birds are
used instead; the question is--how young?
As is widely known, the New Zealand Wildlife Service has been
remarkably successful in recent years in translocating one species
of the endemic wattlebird family--the forest-dwelling saddleback
_(Philesturnus carunculatus)_--to other islands than the four small
ones it had been reduced to by the early 1960's; three of these islands
were the ones recently invaded by ship rats, referred to above.
Predator Control
Some 25 km off the North Island's east coast lies the 3,000-ha, very
rugged and forested Little Barrier Island, which has now been a reserve
for the protection of flora and fauna for about 80 years. Before that,
it had been almost continually occupied by Maoris since their arrival
in New Zealand, and about one-third of its forest was felled or burnt,
especially after European settlement of the adjoining New Zealand
mainland began.
Most unusually, Little Barrier is now free of any grazing or browsing
mammals, and has only the Polynesian rat (a reminder of the Maori
occupation) and feral cats (a European legacy) to impair its extreme
importance as a reserve. The rats have been unmolested by man because,
rightly or wrongly, they are considered ineffective predators
generally; however, their impact has probably been under-rated. More
than half a century of trapping and hunting of cats by successive
caretakers on the island has not effectively reduced that population.
Among its other important attributes, Little Barrier supports two
birds endemic to New Zealand--the rare black petrel _(Procellaria
parkinsoni)_, and one endemic honey-eater, the stitchbird _(Notiomystis
cincta)_, which was once widespread on the North Island but is now
found only on Little Barrier in moderate numbers, and apparently in
no immediate danger. The impact of feral cats on stitchbirds has not
been determined, but it is known that cats are seriously affecting the
black petrel especially: they kill at least 90% of the chicks and some
adults annually. Their impact on a locally remnant population of Cook's
petrels _(P. cookii)_ is apparently less severe.
In 1968-69 the Wildlife Service, with veterinary advice and assistance,
added an attempt at biological control to the campaign of poisoning
("1080" in fish was the poison and bait used), trapping, and shooting.
The very specific viral disease--feline enteritis--was introduced by
trapping island cats, infecting them, and then releasing them. Some
estimates of the resulting mortality from the combined techniques were
as high as 90%; but there has been a recovery since, and the campaign
is expensive in both time and man-power. And, oddly enough, the control
effort has met with some opposition. Nevertheless, another campaign is
planned.
Habitat Rehabilitation by Destruction of Mammals
The Kermadecs are a group of small islands about 800 km north-northeast
of the North Island. Their biological significance, insofar as this
symposium is concerned, is that they are the southernmost breeding
area in New Zealand seas for many elements of the Pacific tropic and
subtropical marine avifauna. Unfortunately, goats were liberated on the
two largest islands--Raoul (3,000 ha) and Macauley (300 ha)--almost
150 years ago and Macauley Island was burnt over; such forest cover as
it had was severely damaged or destroyed, probably at about the same
time. The goats were to be an emergency food supply for whalers and
shipwrecked mariners. Cats, too, became feral on Raoul Island during
one of its fitful periods of occupation. The New Zealand Wildlife
Service, in spite of the distance and difficulties involved, has
undertaken pest destruction campaigns on both islands, but I offer here
only an account of the simpler, and more successful, Macauley operation.
In 1966, a 5-week expedition to this waterless and almost treeless
island resulted in the shooting of what was then thought to be all
of its 3,000-odd goats (a density of about 15/ha). Four years later,
a follow-up expedition found and destroyed another 17 goats (a later
brief inspection suggested that these were indeed the last), and
rehabilitation of the island is well under way. Now that the short turf
is disappearing, erosion of the soft volcanic soils is reduced. With
compaction no longer occurring, it will be interesting to see what the
effect will be on birds breeding on the island--six breeding species of
petrels, three breeding species of terns, and other marine species.
Sociolegal Conservation
The taking of petrels and other procellariiform birds for food has
always been part of the Polynesian economy and culture throughout the
Pacific. In New Zealand, the practice now has only minor economic
importance, but it is still an essential part of Maori culture and
tradition. The most commonly taken species are the sooty shearwater
_(Puffinus griseus)_ and, until recently, the gray-faced petrel
_(Pterodroma macroptera)_. Although no formal study of the impact of
the annual harvest of chicks on the population has yet been made, all
the indications are that it is not significant. Nevertheless, the
Maoris willingly accepted the limited amount of legislation that has
been passed to afford the two principal exploited species at least
token protection. However, on the Chatham Islands, where there is a
strong tradition of taking some of the albatrosses, this tradition has
persisted, even though all albatrosses are fully protected throughout
New Zealand.
Enforcement of legislation in small and isolated communities is not
always easy and sometimes may not be wholly politic. However, the
Maoris of the Chathams have been specially informed of the conservation
issues at stake, and a "gentleman's agreement" has been reached: If
a planned survey shows that full protection of albatrosses in the
Chathams is indeed essential, the Maoris will honor the legislation to
the letter; on the other hand, if limited exploitation seems justified,
the Wildlife Service has agreed that it will be allowed.
Conclusions
Insofar as conservation measures of a passive type are concerned, it
is fortunate that the offshore and outlying islands not yet occupied,
farmed, or set aside as reserves, are likely to remain unexploited,
either because they are too remote for exploitation to be economical
or because they are too inhospitable, or both. In any event, public
opinion is now such that unmodified or otherwise biologically important
islands not already reserved would be proclaimed as reserves if threat
of exploitation arose unexpectedly, unless they were found to be major
sites for oil or minerals. Even so, legislation exists that offers the
possibility of protection even from this threat, and has already been
used to exempt some important mainland areas from prospecting and the
granting of mining rights.
It is gratifying to realize that, although some endemic marine
subspecies (generally not very different from neighboring subspecies)
are endangered to varying degrees, there are very few whose
disappearance would result in the disappearance of the species itself
from the New Zealand area. Only one endemic marine species has become
extinct in recent times, the Auckland Island merganser _(Mergus
australis)_ in about 1905, and only six are currently in any real
danger: the Chatham Island taiko _(Pterodroma magentae)_, the black
petrel, Hutton's shearwater _(Puffinus huttoni)_, the Westland black
petrel (_Procellaria westlandica)_, the shore plover, and the Chatham
Island oystercatcher _(Haematopus chathamensis)_. However, a list
of this kind is often a matter of some controversy. Something is at
present being done to help all but the first and last of these. The
Chatham Island taiko had not been positively identified for about 50
years, until 1977 when this species was "rediscovered" on the main
island of the Chatham group; though its numerical status is unknown,
it is rare. The Chatham Island oystercatcher, although certainly
"threatened" (only about 50 are known to exist), does occur on four
islands, two of which are reserves. Although this species has not been
actively studied until now, it is soon to be the subject of a full
ecological survey.
A few words about the hunting of marine species: Mutton-birding
aside--that is, apart from the taking by Maoris of the young of the
sooty shearwater and the gray-faced petrel--there has been no legal
hunting of any marine birds in New Zealand for 35 years now, nor is
there likely to be. This situation reflects the consistently increasing
weight of informed public opinion in favor of, let alone scientific
concern for, transoceanic migrants. The pro-hunting lobby for some
species of waders, in particular the eastern bar-tailed godwit _(Limosa
lapponica baueri)_, is a small one, the numbers of which decrease
yearly. However, small-scale poaching occasionally occurs; it is
punished when discovered.
Protection for marine species extends only to the 3-mile limit of New
Zealand's territorial waters, but it would be extended further should
New Zealand follow the present trend of including as territorial waters
all those that cover the continental shelf or beyond. [This extension
occurred in 1977; the marine fishing zone for New Zealand waters has
been extended to 200 miles (360 km) around all coasts.]
Only three marine species are not afforded full protection under
the Wildlife Act: two, the black-backed or Dominican gull _(Larus
dominicanus)_ and the black shag _(Phalacrocorax carbo)_, are
totally unprotected--the first because of its predation on some rare
shorebirds during the breeding season and for its attacks on sheep and
lambs at a similar time, and the second because of its depredations
(seldom serious) on the introduced trout and salmon, mainly in fresh
waters--the third species, the southern skua _(Stercorarius skua
lonnbergi)_, may be destroyed only when it is actually attacking
sheep or lambs, an occasional event confined to the Chatham Islands.
Destruction of these three common species is not encouraged by the
Wildlife Service except when black-backed gulls become too active among
colonies of, say, the fairy tern _(Sterna nereis)_, which is very rare
in New Zealand but not elsewhere in its range. Otherwise, control
of the species is left in the hands of those most affected by their
depredations but whose judgment is usually reasonable.
Marine birds, therefore, are generally satisfactorily protected by
law or managed for conservation in New Zealand--especially when one
considers the remarkable changes that have occurred in the New Zealand
archipelago over the last 200 years. Although the situation could be
better, it would certainly have been worse if the Wildlife Service (and
other conservation organizations) had not been untiring in keeping the
general public and the legislature aware of the issues at stake and
seen to it that as much as possible of the necessary conservation work
was done--and done before it was too late.
Acknowledgments
I thank my Wildlife Service colleagues, B. D. Bell, M. J. Imber, D. V.
Merton, and C. J. R. Robertson, for valuable comments and advice on the
preparation of this paper.
References
Atkinson, I. A. E., and B. D. Bell. 1973. Offshore and outlying
islands. Pages 372-392 _in_ G. R. Williams, ed. The natural
history of New Zealand. A. H. & A. W. Reed, Wellington.
Bourne, W. R. P. 1967. Subfossil petrel bones from the Chatham
Islands. Ibis 109:1-7.
Kinsky, F. C. 1970. Annotated checklist of the birds of New
Zealand. A. H. & A. W. Reed, Wellington.
Gibb, J. A., and J. E. C. Flux. 1973. Mammals. Pages 334-371 _in_
G. R. Williams, ed. The natural history of New Zealand. A. H. &
A. W. Reed, Wellington.
Williams, G. R. 1973. Birds. Pages 304-333 _in_ G. R. Williams,
ed. The natural history of New Zealand. A. H. & A. W. Reed,
Wellington.
Williams, G. R. 1977. Marooning--a technique for saving threatened
species from extinction. Int. Zoo Yearb. 17:102-106.
Marine Birds in the Danish Monarchy and Their Conservation
by
Finn Salomonsen
Chief Curator of Birds
The Zoological Museum
University of Copenhagen
Copenhagen, Denmark
Abstract
Most species of seabirds that regularly breed
in Denmark are declining, for a variety of
reasons: shooting; oil pollution; toxic
chemicals; reclamation of land; collecting
of eggs; disturbance at breeding sites
by visitors, motorboats, camping, etc.;
destruction by predators; and others. On the
other hand, the numbers of certain other
species are increasing as a result of climatic
changes (six species), protection (three
species), and increase in food supply (three
species of gulls). In addition to breeding
birds, a total of about 3 million birds occur
in Danish waters as passage migrants or winter
visitors. More than half of the European winter
populations of a number of marine waterfowl
species winter in Denmark. Large numbers of
seabirds spend the summer in Danish waters,
including several hundred thousand immature
gulls and just as many molting waterfowl.
The seabird fauna of the Faroe Islands is
very rich, the immense number of birds
being attracted by the local abundance
of macroplankton and fish. The seabirds
are harvested by man, formerly by fowling
(capturing and shooting), now primarily by
shooting. Until about 1910, more than 400,000
birds were taken annually by fowling. The
Faroese game act is now very restrictive, and
most seabird populations appear to be almost
stable. However, a census in 1972 indicated
that common murres _(Uria aalge)_ have declined
by about 20% to a population of about 600,000.
Shooting and snaring appear to be the primary
causes of the decline; oil pollution and toxic
chemicals do not seem to be contributing to the
population decrease.
In Greenland seabirds provide an important
source of human food; however, because of the
increase in human population and in the use
of guns and speedboats for hunting, and the
absence of a game act, serious overshooting
of seabirds is taking place. A new game act
passed in 1977 should largely alleviate
this overharvest. Oil pollution and toxic
chemicals do not yet play an important part
in influencing the number of seabirds, though
offshore oil drilling is being initiated in
West Greenland. A recently established gigantic
national park, covering 200,000 km² of ice-free
land, is the largest nature reserve in the
world.
The Danish Monarchy consists of three parts far removed from each
other, scattered in the North Atlantic--namely Denmark proper, the
Faroe Islands, and Greenland. They differ so much from each other in
climate and in bird life that they must be treated separately in this
paper. The Faroes possess a provincial government and also a sort
of home rule. Greenland also has a provincial government, but all
statutory provisions, including acts concerning hunting or wildlife
protection, must be passed by Danish authorities, usually by the
Ministry of Greenland.
Insofar as seabirds are concerned, it is important that Greenland is
an arctic country, whereas the Faroes and Denmark are boreal. In both
Greenland and the Faroes the breeding birds are most significant, from
an ecological point of view, whereas in Denmark the passage migrants
and winter visitors are far more important.
There are other differences as well. In Greenland and the Faroes the
seabirds mostly breed in colonies on high and steep cliffs, and the
structure of these breeding places is not disturbed by man. In Denmark,
on the other hand, the seabirds usually breed on glacial deposits, now
forming meadows, low islets, salt marshes, etc., and these habitats
have unfortunately been largely changed in the last hundred years by
draining and reclamation. This practice has taken place in Denmark on a
much larger scale than in most other countries and has, therefore, to a
high degree diminished the life conditions of seabirds.
Seabirds in Denmark
Denmark is situated on the continental shelf of western Europe; all
seas surrounding the country are shallow (less than 100 m deep), apart
from the Skagerrak, north of Jutland, which is much deeper. The shallow
depth, combined with the rapid flow of water between the Baltic and the
North seas causes much upwelling, which forms excellent life conditions
for plants and animals. It is well known that the fishery in Danish
waters, especially in the North Sea, is very rich. This richness of the
seas provides suitable conditions for a high diversity of seabirds and
ecological types.
Seabirds regularly breeding in Denmark include five species of terns
(common tern, _Sterna hirundo_; arctic tern, _S. paradisaea_; least
tern, _S. albifrons_; Sandwich tern, _S. sandvicensis_; and gull-billed
tern, _Gelochelidon nilota_); seven species of gulls (black-headed
gull, _Larus ridibundus_; herring gull, _L. argentatus_; lesser
black-backed gull, _L. fuscus_; great black-backed gull, _L. marinus_;
mew gull, _L. canus_; little gull, _L. minutus_; and black-legged
kittiwake, _Rissa tridactyla_); four species of geese, swans, and
ducks (mute swan, _Cygnus olor_; greylag goose, _Anser anser_; common
eider, _Somateria mollissima_; common merganser, _Mergus merganser_;
and red-breasted merganser, _M. serrator_); three species of auks
(black guillemot, _Cepphus grylle_; common murre, _Uria aalge_;
and razorbill, _Alca torda_); and one species of cormorant (great
cormorant, _Phalacrocorax carbo_). Shorebirds have not been included
in this review. Some of the species mentioned are partly freshwater
birds--for example, the black-headed gull, little gull, mute swan,
greylag goose, and the two species of mergansers. The gull-billed tern
forages in terrestrial habitats, but nests along the coast with the
other seabirds. It is often difficult, therefore, to make a clear-cut
distinction between seabirds and freshwater birds.
Among the auks, the black guillemot breeds in the Cattegat area in the
huge heaps of boulders on small raised islets, or in holes (mostly
formed by starlings, _Sturnus vulgaris_) on steep clayey slopes or
promontories. The common murre and razorbill are restricted to the
islet Graesholm in the Christiansø Archipelago, about 24 km east of
Bornholm Island in the Baltic, where they breed on small cliffs of
Precambrian granite rock.
The estimated number of seabirds of different species that breed
in Denmark is shown in Table 1. Species like the mergansers, mute
swan, and greylag goose, which breed partly or mostly in freshwater
localities, are not included. Overall, the number of breeding seabirds
is slowly declining, probably due to many factors which are discussed
below. There are two exceptions, however, to this general decrease--the
herring gull (and to a lesser degree the other big gull species) and
common eider. Both species have increased during the last 50 years.
Since they breed in the same habitat, usually mixed together, the
eider is probably dependent on herring gulls for protection against
predators. When the ducklings are fledged, the herring gull acts as
a successful predator itself, but the eider nevertheless maintains a
close association with herring gulls.
Table 1. _Estimated average number of breeding pairs of seabirds
in Denmark, based on a census in 1970-72._ (Data for terns from
Mardal 1974, and for other species from Sten Asbirk and N. O.
Preuss, personal communications.)
Number of
breeding
Species pairs
_Sterna paradisaea_ 5,750
_S. hirundo_ 900
_S. sandvicensis_ 4,000
_S. albifrons_ 600
_Gelochelidon nilotica_ 105
_Larus marinus_ 300
_L. argentatus_ 60,000
_L. fuscus_ 2,000
_L. canus_ 28,500
_L. ridibundus_ 135,000
_L. minutus_ 25
_Rissa tridactyla_ 125
_Phalacrocorax carbo_ 600
_Somateria mollissima_ 3,800
_Cepphus grylle_ 325
_Alca torda_ 400
_Uria aalge_ 1,100
Total 243,530
More than 90% of the herring gull population breeds on small islands,
and a large proportion occurs in a few large colonies. It never breeds
in freshwater localities, but is exclusively found as a breeding
bird in coastal habitats. The population has particularly increased
in the last 5 decades, some colonies reaching their maximum size in
the 1960's. Others are still expanding and occupying new breeding
grounds. Today the largest colonies are found on the following islands:
Saltholm, 20,000-40,000 pairs; Christiansø 9,000 pairs; Hirsholmene,
2,500 pairs; Jordsand, 1,800 pairs; Samsø, 2,000 pairs; Hjelm, 1,500
pairs; and the archipelago south of Funen, a total of 3,500 pairs in
several colonies.
Attempts have been made to reduce the breeding population of herring
gulls at Hirsholmene and Christiansø sanctuaries (in 1973 and 1974,
respectively), to improve conditions for other nesting seabirds. In
1969 the Bird Strike Committee of the Royal Danish Airforce also
initiated a program to reduce the number of herring gulls breeding
on Saltholm Island, which is near the Kastrup airport in Copenhagen.
Nests were sprayed with a formaldehyde oil dye, which resulted in a
33% reduction in population. In Christiansø and Hirsholmene, where the
adult breeding birds were poisoned, the effect is not yet known.
The total number of seabirds occurring in the Danish waters as
passage migrants and winter visitors is substantially larger than the
breeding population, because Denmark is situated on a very important
fall migration route for seabirds from Scandinavia, the Baltic
countries, northern Russia, and northwestern Siberia. Furthermore, the
shallow waters of the Danish seas (less than 10 m deep) that occupy
extensive regions bordering the coasts are important feeding grounds
for diving ducks. Birds frequenting the seas outside the breeding
season include hundreds of thousands, or probably millions, of gulls;
numerous ducks (especially diving ducks); swans and brants, _Branta
bernicla_; jaegers, _Stercorarius_ spp. (four species); loons, _Gavia_
spp. (four species); grebes, _Podiceps_ spp. (four or five species);
gannet, _Morus bassanus_; great cormorant; northern fulmar, _Fulmarus
glacialis_; common murre; razorbill; and other species of alcids.
To these should be added a number of species of various seabirds,
especially gulls, tubenoses, phalaropes, and others which appear as
casual or accidental visitors and which are not further mentioned in
this paper.
Table 2. _Total numbers of ducks, swans, and coots recorded in
Denmark during a winter census in January 1973 (based on ground
counts and aerial surveys), compared with estimated flyway
populations wintering in western Europe and annual bird harvest
in Denmark (after Joensen 1974:23, 155, 168)._
Estimated winter Average
Census, populations of the annual bag
Species January 1973 Western Europe Flyway in Denmark
_Anas platyrhynchos_ 127,000 1,550,000 380,000
_A. crecca_ 500 260,000 76,000
_A. querquedula_ 11 [67] [68]
_A. acuta_ 100 70,000 13,000
_A. strepera_ 5 [67] [69]
_A. penelope_ 3,000 485,000 44,000
_A. clypeata_ 17 63,000 9,000
_Tadorna tadorna_ 13,000 105,000 [69]
_Aythya ferina_ 7,100 235,000 5,000
_A. fuligula_ 94,700 530,000 35,000
_A. marila_ 80,900 145,000 8,000
_Clangula hyemalis_ 11,000 [67] 11,000
_Melanitta nigra_ 148,100 [67] 18,000
_M. fusca_ 6,700 [67] 9,000
_Somateria mollissima_ 450,800 [67] 136,000
_Bucephala clangula_ 67,000 142,000 25,000
_Mergus serrator_ 11,700 40,000 8,000
_M. merganser_ 23,200 75,000 6,000
_M. albellus_ 206 5,000 [69]
_Cygnus olor_ 48,900 120,000 [69]
_C. cygnus_ 5,700 17,000 [69]
_C. bewickii_ 1,113 6,000 [69]
_Fulica atra_ 142,500 [67] 70,000
Totals 1,243,252 3,848,000 853,000
A comprehensive investigation of the nonbreeding waterfowl in Danish
waters was recently undertaken by the Game Biology Station Kalø
(Joensen 1974). Aerial surveys of marine ducks indicate that a large
percentage of the ducks that winter in European waters do so in the
shallow areas of the Danish seas. A census in January 1973 indicated
a total of more than 1.2 million birds (Table 2). In a number of
other countrywide surveys, undertaken in all winters since 1967,
usually 1.0-1.5 million birds have been recorded. Since such censuses
usually give minimum numbers, and certain species-especially marine
ducks--generally go unrecorded, the normal winter population (November
to February) of ducks, swans, and coots in Danish waters can scarcely
be less than 2 million birds (Joensen 1974:156). In Table 2, bird
numbers in Denmark are compared with the estimated winter populations
in western Europe, based on the investigation of Atkinson-Willes
(1972). When all the winter censuses in Denmark are compared with
those for Europe, as was done by Joensen (1974:156), it is evident
that Danish waters support about half of all greater scaup _(Aythya
marila)_, common goldeneye _(Bucephala clangula)_, red-breasted
merganser, mute, whooper _(Cygnus cygnus)_, and tundra swans _(C.
bewickii)_ wintering in Europe; about one-third of the population of
tufted duck _(Aythya fuligula)_ and common merganser; and probably also
one-third of the population of common eider and coot _(Fulica atra)_.
The wintering population of common eider is very large. According to
banding records it makes up the greater part of Baltic breeding birds;
however, it is not possible to calculate its percentage contribution
to the total European winter population since its size is unknown in
most European countries. Although most of the surface-feeding ducks
disappear from Denmark waters in winter, extremely large numbers occur
there during the fall migration period. For example, it has been
estimated that for species like common teal _(Anas crecca)_ and wigeon
_(A. penelope)_ about one-third of the West European Flyway population
passes Denmark in the fall. Possibly some of the surface-feeding ducks
listed in Table 2 for January 1973 were recorded in fresh water and not
from the seas, but at the time the census was taken most freshwater
lakes were frozen and, therefore, unavailable for water birds.
These breeding seabirds and the off-season visitors do not constitute
the total population in Danish waters. Large numbers also occur in
summer as nonbreeding birds; most are in two categories: (1) several
hundred thousand pre-adult (up to 4-5 years of age) gulls (mostly great
black-backed, herring, and lesser black-backed gulls), which feed
inshore or at the coast, and (2) large concentrations of waterfowl that
carry out a molt migration in Danish waters, particularly in shallow
areas. Black scoter _(Melanitta nigra)_, velvet scoter _(M. fusca)_,
common eider, and whooper swan are especially numerous, totaling
hundreds of thousands of individuals, and probably constituting the
majority of the European molting populations of these species. Less
numerous, but still totaling thousands of molting birds, are sheld-duck
_(Tadorna tadorna)_, common goldeneye, red-breasted merganser, and
possibly some other diving ducks. About 3,000 surface-feeding ducks of
various species, most of which undoubtedly are local breeding birds
undergo wing molt in Danish waters. Comprehensive descriptions of the
molt migration, particularly in Denmark, were published by Salomonsen
(1968) and Joensen (1973_a_, 1974).
It may then be concluded that very large numbers of seabirds are found
in Danish waters in all periods of the year; most feed in the inshore
zone and some offshore, but none in the pelagic zone.
_Increase of Seabirds_
Seabirds are affected by several factors related to human activities,
most of which pose a threat to them and will eventually reduce their
numbers. Some factors, however, tend to increase bird numbers, like
climatic changes which, as reported by Salomonsen (1963), have given
rise to the immigration to Denmark of great cormorant (in 1938); eared
grebe, _Podiceps nigricollis_ (about 1870); red-crested pochard, _Netta
rufina_ (1940); common pochard, _Aythya ferina_ (about 1860); tufted
duck (about 1900); and common murre (1929). They all still breed in
Denmark, having more or less increased in number.
Another reason for increases of certain species is legal protection.
Among protected seabirds are the sheld-duck, which has been completely
protected since 1931, and particularly the mute swan, of which only 2
or 3 pairs were breeding in Denmark when the species was completely
protected in 1926. Since then, mute swans have increased enormously,
reaching at least 2,740 pairs in 1966 (Bloch 1971:43), of which large
numbers were breeding colonially on small islets of boulders or on sand
reefs off the coast (Bloch 1970:152). The gannet has also increased
considerably as a fall visitor since about 1945, apparently due to
protection in England and other countries.
Finally, some gull populations have increased in size because of an
increase in the food supply, consisting especially of wastes from
commercial fisheries and garbage dumps. In Denmark, this unnatural food
source has caused an enormous increase since about 1925 in herring
gulls (from less than 500 pairs to 60,000 pairs), lesser black-backed
gulls (all three subspecies, _fuscus_, _intermedius_, and _graelsii_
have immigrated to Denmark), and great black-backed gulls (immigrated
to Denmark in 1930). Improved waste disposal practices in recent years
have not yet offset the rate of growth of these gull populations.
The increase of common eiders, which also started in about 1925, is
probably related to the increases in the larger gulls.
_Decrease of Seabirds_
A variety of factors tend to reduce the numbers of seabirds. The most
important ones are outlined below, with comments on what has been done
or what is expected to be done to reduce the impact of these activities
on seabirds and protect this endangered resource.
Shooting of Seabirds
The shooting of seabirds in Denmark is considerable, because the
seabirds are extraordinarily numerous, and the number of sportsmen is
very large, amounting to about 135,000 (a larger number per capita than
in any other country).
The Danish game statistics are excellent--well known to be much more
accurate than in most other countries (see Salomonsen 1954; Strandgaard
1964). According to Danish bag records, almost one million ducks,
geese, and coots (Joensen 1974:31) and about 100,000-200,000 gulls
(Salomonsen 1954:125) are shot each year. The average annual bag of
each species of wildfowl is given in Table 2 and the open season for
each species of seabirds in Table 3. The open season for dabbling ducks
is long, extending from 16 August to 31 December, which means that
local birds are persecuted almost as soon as birds-of-the-year are able
to fly. This has resulted in a dabbling duck breeding population that
is much smaller than what the available food supply could support, and
in the large-scale development of artificial rearing of mallards for
later shooting. A 5-month hunting season on specialized birds like
loons, grebes, and various auks is not good management practice and
should be carefully reviewed.
Four other important facts about the shooting of seabirds in Denmark
merit inclusion here: (1) there is no bag-limit for any species; (2)
in general, all marine areas within territorial limits are open to
all Danish sportsmen, and the admission is free; (3) motorboats with
a maximum speed of 10 knots are allowed for shooting in the period 1
October-30 April; and (4) the shooting of seabirds is permissible from
1.5 h before sunrise to 1.5 h (in December 1 h) after sunset, whereas
for most other birds shooting is prohibited between sunset and sunrise.
Shooting is a national tradition in Denmark, and the large number of
sportsmen has considerable political power. Too much influence is given
to the representatives of the hunters' organizations, which have the
decisive force in game committees dealing with protective measures. It
is difficult, therefore, to change the existing system.
Table 3. _Open hunting seasons for seabirds in Denmark, according
to the Game Act of 1967. Species not given in the table are fully
protected._
Hunting period and species
1 August-31 December
_Anser anser_
_A. fabalis_
_A. brachyrhynchus_
_A. albifrons_
_Branta bernicla_[70]
_B. canadensis_
1 August-30 April
_Phalacrocorax carbo_
16 August-31 December
_Anas platyrhynchos_
_A. crecca_
_A. querquedula_
_A. acuta_
_A. penelope_
_A. clypeata_
16 August-29 February
_Aythya ferina_
_Fulica atra_
_Larus ridibundus_
_L. canus_
16 August-30 April
_L. fuscus_
_L. argentatus_
_L. marinus_
1 October-29 February
_Aythya fuligula_
_A. marila_
_Clangula hyemalis_
_Melanitta nigra_
_M. fusca_
_Somateria mollissima_
_Bucephala clangula_
_Mergus serrator_
_M. merganser_
_Gavia stellata_
_G. arctica_
_G. immer_
_Podiceps cristatus_
_Uria aalge_
_U. lomvia_
_Alca torda_
Shooting of seabirds, especially various waterfowl, is popular and
intensive. The number of ducks taken by Danish sportsmen is probably
in the order of 10-15% of the total kill on the West European Flyway
(Joensen 1974:171). Excessive duck shooting can, in some cases, be
controlled by banding in the breeding areas; the ensuing results then
give rise to strong protests from the Scandinavian countries against
the extensive persecution. As stated above, Denmark has (in relation to
its size) the largest number of sportsmen of any nation in the world
and the most intensive shooting. The number of sportsmen shooting
ducks and shorebirds per 100 km² is 278 in Denmark, 28 in Sweden, 37
in Finland, 10 in Poland, 83 in Holland, 164 in Britain, and 129 in
Western Germany; the number of ducks shot per 100 km² is 1,856 in
Denmark, 39 in Sweden, 68 in Finland, and 129 in Western Germany (Nowak
1973). This shooting is undoubtedly of importance to dabbling duck
populations, which are popular as shooting objects everywhere in Europe.
Insofar as marine ducks are concerned, it can be seen in Table 2 that
appreciable numbers are shot in Denmark. The same is true for other
Scandinavian countries, whereas shooting on the high seas is rather
modest in most other European countries. The Danish bag undoubtedly
makes up a significant proportion of the total number of marine ducks
killed each year, but when the total number of ducks in European waters
is considered, the shooting pressure in Denmark appears to be of only
minor importance. However, the shooting, particularly when undertaken
from motorboats, is so noisy and makes such a disturbance over large
areas that the time for seabirds to rest and forage is significantly
reduced. It must also be noted that the number of pleasure craft is
steadily increasing in the present period of prosperity, and that
increasing numbers of sportsmen will probably make use of the free
shooting in territorial waters, since it is becoming more and more
expensive to lease hunting areas.
To restrict seabird shooting, the Danish Ornithological Society has
recently (1975) submitted a proposal to the Danish Government, of which
the following points are relevant:
• The open season for dabbling ducks and geese should begin 15
September except for pintail _(Anas strepera)_, shoveler _(A.
clypeata)_, wigeon, and pochard--species which should not be hunted
until 1 October;
• the open season for all diving ducks, as well as for coot, should end
31 December;
• the open season for the great cormorant should be restricted to the
period between 15 September and 31 October;
• murres, razorbill, great-crested grebe _(Podiceps cristatus)_, and
all species of loon should be fully protected;
• it should be prohibited to shoot from motorboats less than 1 km from
the shoreline, as well as in certain narrow sounds and fjords;
• it should be prohibited to shoot from shooting-punts less than 100 m
from the shoreline;
• it should be prohibited to sell waterfowl and shorebirds shot, except
for eider ducks and mallards _(Anas platyrhynchos)_; and
• no shooting should be allowed between sunset and one hour before
sunrise.
Oil Pollution
Oil pollution incidents constitute one of the greatest dangers to
seabird populations in Danish waters. The enormous masses of seabirds
present in these waters throughout the year, combined with the fact
that Danish waters contain some of the heaviest shipping traffic in the
world would give rise to anxiety for oil disasters. The majority of all
tanker traffic from the Atlantic and the North Sea to the Baltic passes
through the Cattegat and the narrow straits of the Sound, the Great
Belt, and the Little Belt, to supply a population of about 100 million
people. Up to 100,000 ships pass through these waters each year, half
through the Sound.
There have been severe oil pollution disasters every year since about
1935, accompanied by enormous mortalities of seabirds, particularly
marine ducks. The Danish Game Biology Station, which has studied these
disasters (Joensen 1972_a_, 1972_b_, 1973_b_), has noticed that the
number of seabirds involved has increased in recent years, in spite of
increased control by Danish authorities.
Unfortunately, it appears that small amounts of oil in the sea,
originating from cleaning the tanks of vessels, or from the release
of a few tons of oil, are enough to create mass mortality of seabirds
when large concentrations of birds are present in the vicinity. Such
incidents have passed unnoticed in spite of control measures. In no
case has the source of the pollution been traced (Joensen 1972_b_:27).
There has not yet been a real "oil disaster" in the Danish waters
similar to the _Torrey Canyon_ catastrophe. If such a disaster takes
place, the destruction of seabirds will be enormous and immeasurable.
Table 4. _Species composition of 8,304 birds killed by oil and
examined in connection with five pollution disasters in the
Cattegat, 1969-71._ (After Joensen 1972:12.)
Oil incident no.
Species 1 2 3 4 5 Totals
_Gavia stellata_ 1 9 1 4 15
_G. arctica_ 2 2 4 8 16
_Gavia sp._ 4 1 5
_Podiceps grisegena_ 4 1 8 8 21
_P. cristatus_ 1 1
_Phalacrocorax carbo_ 20 20
_Anas platyrhynchos_ 2 2 4
_A. clypeata_ 2 2
_Aythya marila_ 6 2 8
_Clangula hyemalis_ 35 2 26 6 4 73
_Melanitta nigra_ 387 241 521 262 77 1,488
_M. fusca_ 197 33 417 223 119 989
_Somateria mollissima_ 1,683 1,081 947 1,713 19 5,443
_Bucephala clangula_ 3 3 13 9 28
_Mergus serrator_ 48 28 28 2 106
_Cygnus olor_ 10 17 1 28
_C. Cygnus_ 1 1
_Fulica atra_ 1 1 2 5 9
_Larus sp._ 13 13
_Alca torda_ 1 12 1 14
_Uria aalge_ 1 1
_Cepphus grylle_ 1 2 16 19
Total birds examined 2,380 1,362 1,996 2,324 242 8,304
Estimated minimum number
of birds killed 10,000 5,000 12,000 15,000 1,500 43,500
Percent of total birds contributed
by three species[71] 95.3 99.5 94.4 94.6 88.8 95.4
As a result of five of the major oil pollution incidents in the
Cattegat from 1969-71, a total of 43,500 birds were killed, of which
8,304 were examined and enumerated (Table 4). Altogether, 21 or 22
species were involved, but 95% of all birds examined were diving ducks:
common eider and black and velvet scoters. At present, it has not
been possible to identify any decrease in the number of these ducks
in Danish waters due to oil pollution. However, if these disasters
continue, it can be expected that duck populations of northern Europe
and the Baltic area will be severely reduced, and that an overall
decline will take place from which the birds may not be able to recover.
A particularly disastrous year was 1972, when large numbers of ducks
were killed as a result of rather small oil spills. A tanker disaster
in March 1972 off the eastern coast of Jutland, in the northern
Cattegat, and another in December 1972 in the Danish Waddensea, both
took place in areas critical to major concentrations of sea ducks.
A total of more than 60,000 birds were killed, of which about 95%
consisted of the same three species of diving ducks mentioned above.
These tragic events represent a further increase in the annual
mortality of birds caused by oil, and there is reason to believe that a
critical upper limit is rapidly being approached.
It appears, however, that the measures taken by pollution control and
naval authorities have greatly improved in recent years. In January
1973, when a Polish merchant vessel collided with a Swedish tanker in
the Sound, about 300 tons of heavy fuel oil were released into the sea.
Several Danish and Swedish ships working in cooperation succeeded in
dispersing the oil, and no serious effect on seabird populations took
place (Joensen 1973_b_:118). It seems that the best way of cleaning up
such oil disasters is through a mechanical removal of the oil, but this
is a very expensive and difficult procedure.
Pollution by Toxic Chemicals
Chemical pollution is probably the most ominous threat to seabirds
at present. Since all toxic chemicals used in agriculture ultimately
end up in the sea, and many large factories release their industrial
wastes directly into the sea, the effects of this pollution on marine
organisms is attracting a growing interest. Many students have worked
on these problems, and the results that concern birds were summarized
by Bourne (1972:205). It is known that organochlorine residues have
been found in seabirds in all the oceans of the world, including
Antarctic waters and Arctic seas (Bogan and Bourne 1972:358). The
chemicals most often found in birds are DDE (a metabolite of DDT)
and PCB's (polychlorinated biphenyls), a mixture of related chemical
compounds often originating from industrial wastes. In addition, some
mercury will always be found, sometimes in increased concentrations.
The present restrictions on the use of DDT and PCB in Denmark have
not yet resulted in a corresponding decrease in the amount of these
pesticides in birds.
It is well known that marine pollution reaches a peak in the Baltic.
This high level of pollution is reflected in seabirds. For example,
analyses have shown that eggs from the colony of common murres on
Christiansø in the Baltic contain about 100 times as much DDE and 50
times as much PCB as eggs of murres from the Faroe Islands in the
Atlantic Ocean (Dyck 1975).
A similar difference exists in the mercury content in birds examined
in the two areas. Feathers of a large sample of black guillemots and
murres from the Cattegat and the Baltic had higher mercury levels than
those from the Faroe Islands and Greenland. It is interesting that
this difference existed over a hundred years ago, as evidenced by the
analysis of feathers in museum specimens. The Baltic populations of
both species show very significant increases in the mercury content
in 1965-70, as compared with the values earlier in this century.
Since 1970 there has been a sharp decrease in mercury content, and
in 1973 the level was almost as low as it was early in the century.
These results indicate that the strict control of mercury discharges
enforced in Sweden has resulted in a quick recovery of nearly normal
conditions in the Baltic (Somer and Appelquist 1974). However, recent
studies by Koeman et al. (1975:286) appear to show that mercury does
not accumulate to the same extent in seabirds as it does in seals.
High concentrations of chlorinated hydrocarbon residues accumulate in
carnivorous birds and upset the normal breeding behavior by making the
eggshells too thin and fragile to survive (Peakall 1970:73; Mueller
and Leach 1974:289). In Denmark, shells of herring gull eggs from the
Baltic population were thinner, lighter, and more heavily contaminated
with DDE and PCB than were shells of eggs from other colonies
(Jørgensen and Kraul 1974:173). This further emphasizes the pollution
of the Baltic Sea.
Massive mortalities of common murres, such as the one reported in the
Irish Sea in the fall of 1969 which was apparently caused partly by
malnutrition and PCB poisoning (Parslow and Jefferies 1973:87), are
unknown in Danish waters.
It should be added that the pollution of seawater with cadmium, so very
dangerous for man, has been high in recent years owing to the increased
use of this element in industry, but no analysis of its importance for
seabirds in Danish waters has yet been made.
It should also be mentioned that pollution of fresh water in lagoons
or lakes near the sea can often cause serious declines in numbers of
certain seabirds. This is well illustrated by recent events in the
sanctuary Nakskov Indrefjord on the island of Lolland. This landlocked
fjord once supported numerous breeding populations of ducks, grebes,
and terns, but in recent years a number of species (e.g., eared grebe;
common teal; garganey, _Anas querquedula_; pintail; and black tern,
_Chlidonias nigra_) have failed to breed and practically all other
species have declined in numbers. The main reason for these changes is
a severe pollution from the admission of raw sewage from tributaries
(Bloch et al. 1972). After several outbreaks of botulism in recent
years, procedures to improve conditions are now being developed.
Other Threats to Seabirds
The most dangerous threats to seabirds are those discussed above.
Authorities are aware of these dangers and attempts are being made
to improve conditions. Some results have been achieved in the combat
against oil pollution, and the control of shooting is reaching an
acceptable level. Game management agencies in Denmark and other
Scandinavian countries (Norway, Sweden, and Finland) are cooperating on
the request of the parliamentary body of the Nordic Council. If game
biologists in these countries could agree on proposed changes in the
game acts, owing to the marked decline of a number of bird species, the
parliamentary basis for such a legal step would be absolutely certain.
However, it must be admitted that the impact of man on the environment
is enormous, especially in a country like Denmark, which possesses
no raw materials, and where agriculture has transformed the whole
country. In such a country, the birds have to "face the music," and by
this sharing of resources with man, they will inevitably decrease in
number. It is the responsibility of biologists and politicians, without
emotional biases, to find the balance between the requirements of the
two spheres of interest.
Many other dangers that threaten seabirds, some of which are unrelated
to human activities, are listed here.
• Land reclamation.--Reclamation of land has reduced extensive areas of
shallow water, lagoons, marsh land, etc., from seabirds for foraging
or breeding places. Draining and diking of coastlands, estuaries, and
saltings have had the same effect. This activity is now almost stopped,
as these projects are no longer subsidized by the government.
• Egg-collecting.--According to the present game act, collecting gull
eggs is permitted until 24 May. This creates much disturbance on the
breeding grounds, and eggs of terns and shorebirds are also taken.
This practice should be halted. The "Bird Island Group" of the Danish
Ornithological Society, in a symposium in 1972, prepared some rules
for the protection of seabirds, among which is a proposal to stop
egg-collecting.