fenced in, even small uninhabited islets, as common property. People
have free access to such areas with the result that seabirds breeding
in colonies, or separately on islands, are disturbed by visitors
arriving by boat. At the same time, noisy motorboats, bathing parties,
or camping visitors frighten the birds, making successful breeding
almost impossible. Even ornithologists, bird-banding teams, and bird
photographers add to the destruction. The "Bird Island Group" of the
Danish Ornithological Society has proposed a general prohibition
against visitors on important bird islands from 1 March to 15 July to
protect the breeding seabirds.
• Destruction by predators.--Fox, ermine, and stone-marten do not play
an essential role. Rats are more important, even on small islands, and
have caused destruction of tern and gull colonies. Rat numbers do not
decline until a severe winter with much ice occurs, or until high tide
kills them all. Large gulls also cause a great deal of destruction, but
crows and magpies are unimportant as predators in seabird colonies.
Numbers of nonbreeding mute swans or greylag geese may sometimes be a
nuisance, trampling eggs and nestlings in seabird colonies.
• Forestry practices.--The prevailing practice of the forestry industry
in Denmark of not preserving old trees with holes has considerably
diminished the breeding habitat of hole-nesting species like the common
merganser. Artificial nest-boxes have now been established in several
areas.
• Sea conditions.--During high water, or rough sea, salt water may
flood colonies of breeding seabirds nesting on low islets, often
reducing the production of young.
• Aircraft disturbance.--Disturbances are also caused by noise from jet
aircraft flying low, especially in military training areas where air
traffic may be heavy.
• Commercial fisheries.--Modern commercial fisheries are depleting
so-called industrially important fish stocks such as sand eels
_(Ammodytes)_, herrings, and other small fish over large areas of the
sea for the production of fish meal. This fishing has undoubtedly been
the main reason for the decline in the number of terns--especially
sandwich terns which depend on these small fish species for food.
• Unknown factors at sea.--Large numbers of pelagic seabirds,
particularly fulmars, kittiwakes, and gannets, are washed up on
the western coast of Jutland in certain years (e.g., 1959, Joensen
1961:212). These birds died at sea, for unknown reasons, and apparently
as a result of food shortages or oil pollution.
_Conservation_
The threats to seabirds mentioned above are all well known to
conservationists, who are attempting to reduce the impact of these
factors on seabirds where possible. Insofar as legal protection is
concerned, it must be admitted that there are no marine sanctuaries
in Denmark, although several discussions have taken place reviewing
the possibility of establishing some in critical areas. There are,
however, a number of sanctuaries on islands where seabirds breed. In
the Sanctuary Act of 1936 these areas were called "Scientific Reserves"
because they were the site of scientific investigations of bird life.
All admission was forbidden, at least during the breeding season, and
all shooting was prohibited, with few exceptions. These sanctuaries
were administered by the government's Nature Conservancy.
The following Scientific Reserves are important for seabirds:
Hirsholmene Islands (in Cattegat off Frederikshavn), Knotterne Islands
(small islets east of Laesø Island), Vejlerne (diked in, landlocked
fjords, densely covered with vegetation, at the Lim Fjord), Tipperne
Peninsula and Klaegbanken Island (in Ringkøbing Fjord, western
Jutland), Varsø Island (Horsens Fjord, eastern Jutland), and Græholm
Island (Christiansø Archipelago, in the Baltic off Bornholm). A
detailed description of these sites and their erection, bird life, and
ornithological value was given by Salomonsen (1945). More recently, two
additional Scientific Reserves have been established: Aegholm Islet
(south of Sealand), and Hesselø Island in the southern part of Cattegat.
In addition to these scientific sanctuaries, there are game reserves
and governmental forest reserves in Denmark. The game reserves are
administered by the Ministry of Agriculture, which is also responsible
for hunting legislation. The purpose of game reserves is to support and
protect the stock of game, which includes migrating birds. Shooting is
usually prohibited, but a restricted shooting season is allowed at some
reserves. More than 50 game reserves are now present and functioning.
Regulations differ widely from reserve to reserve, but entry to some of
them is not allowed in the breeding season. Many reserves are important
for breeding or migrating waterfowl and some seabirds. In fact, a total
of 26 game reserves contain seabirds, the most important of which are
the following: Ulvedybet (landlocked fjord at the Lim Fjord), Hjarbaek
Fjord (landlocked fjord with brackish water at the Lim Fjord), Felsted
Kog (landlocked fjord at Nissum Fjord), Jordsand (large stretches,
almost 11,000 ha, of the Danish Waddensea), Stavns Fjord (at Samsø
Island), Esrum Lake (in northern Sealand), and Kalvebod Beach (at
Amager Island, near Copenhagen).
In the Nature Conservancy Act of 1969, differences between scientific
and game reserves were abolished, although regulatory provisions
that were in force for the scientific sanctuaries were maintained.
Unfortunately, the amalgamation of the two types of reserve has
given more power to the hunters' associations, which constitute the
majority of the administrative body of the reserves, the so-called
Game Commission ("Vildtnævnet"). However, any change in status of the
original scientific reserves will not be tolerated by conservationists
and other environmental groups in Denmark.
The Faroe Islands
The number of seabirds in the Faroe Islands is greater than in any
other region of the North Atlantic, and is closely related to the
extraordinary richness of the plankton. The high phytoplankton
production is due to a strong vertical mixing of the water in the
northeast Atlantic, especially at the slopes of the submarine ridges,
where both tidal currents and oceanic currents are usually strong.
The resulting upwelling enriches the upper layers of water with large
quantities of nutrient salts for the phytoplankton, and this, in turn,
produces a teeming life of macroplankton and fish on which the seabirds
are dependent (Salomonsen 1955).
The enormous seabird population of the Faroes is apparent from the
first description of the islands, "De mensura orbis terrae," a document
written in the year 825 by the Irish monk Dicuilus, who described the
most characteristic feature of the Faroes as being the fact that "the
islands were full of various kinds of marine birds." This richness
has remained to the present, and has provided an important source of
food for the resident human population, particularly in former times.
There are few, if any, countries in the world in which wild-fowling and
other exploitations of birdlife have played such a major role as in the
Faroes. A number of elaborate and varied bird-catching methods were
invented, and these have remained essentially the same for at least the
last 500 years. Bird-fowling at great heights on precipitous sea-cliffs
was a dangerous venture, and each year lives were lost. The main thing,
however, was that food obtained from fowling meant life and death
for local inhabitants and so was undertaken in such a well-balanced
way that the seabird populations did not decrease or disappear. Some
fowling still takes place, but on a reduced scale, since most men are
now engaged in the fishery during the summer. Shooting is now of much
greater importance than in former times.
The Faroese game acts (from 1897, 1928, and 1954) are very severe and
show a broad consideration for birdlife. Practically all terrestrial
birds, including shorebirds, are protected, and existing regulations
permit people to catch or shoot only common murres, razorbills,
puffins, shags _(Phalacrocorax aristotelis)_, fulmars, gannets,
parasitic jaegers _(Stercorarius parasiticus)_, and gulls, as well
as a few "pest" species like crows _(Corvus corone)_ and ravens _(C.
corax)_. The legal right of fowling on a "fowling cliff" belongs to the
registered owner of the land on which the cliff is situated. There are
some sound restrictive laws for these cliffs. For example, shooting
within 3.2 km of any seabird colony is prohibited.
Table 5. _Number of seabirds caught by fowling each year in the
Faroe Islands in the early 1900's._ (From Salomonsen 1935.)
--------------------------------------
Number of birds
Species caught per year
--------------------------------------
_Uria aalge_ 60,000
_Fratercula arctica_ 270,000
_Puffinus puffinus_ 1,500
_Fulmarus glacialis_ 80,000
_Morus bassanus_ 1,300
Total 412,800
--------------------------------------
The annual number of seabirds caught by fowling in the early 1900's
(summarized in Table 5) were reported in Salomonsen (1935). This large
harvest of birds, taken by fowling year after year for centuries,
did not appear to influence the seabird populations, as bird numbers
remained stable. However, in recent years, shooting and a special form
of snaring of murres have increased dramatically and seem to have
endangered the murre population. The annual number of murres killed is
estimated to be about 120,000, of which 70,000 are snared and at least
50,000 shot (estimates of birds shot range from 50,000 to 100,000).
This total is almost double the number of birds caught during fowling,
and because of an apparent decline in murre numbers the provincial
government decided to investigate the matter, and in 1972 the Danish
Ornithological Society agreed to conduct the study. Figures from the
1972 census of murres (Table 6) show that almost 600,000 birds were
counted, from which an estimate of more than 393,000 breeding pairs was
calculated (Dyck and Meltofte 1975). In spite of this large number,
Dyck and Meltofte (1975) concluded that the Faroese murre population
has declined by about 20% during the last 10-15 years. Investigations
are under way to monitor further changes in murre numbers, and to
determine the trend, and whether reductions in shooting and snaring are
necessary to maintain the population.
Oil pollution is practically unknown in Faroese waters, but since
drilling for oil will probably take place in the near future, the
importance of oil to birds in this region may change. Toxic chemicals
do not appear to be involved in the decline in murres. Investigations
of concentrations of chemical pollutants in their eggs show that levels
of DDE (mean 1.1 ppm), PCB (mean 2.0 ppm), and mercury (mean 0.2 ppm)
(Dyck and Meltofte 1975) are relatively low and unlikely to affect
reproduction (Dyck and Meltofte 1975). Levels are much smaller than
those found in seabirds in Britain, the Baltic, or in albatrosses in
the Pacific (Fisher 1973).
Table 6. _Colonies of the common murre,_ Uria aalge, _on the
Faroe Islands, based on a census conducted in 1972._ (After Dyck
and Meltofte 1975.)
----------------------------------------------
Number of
birds Number of
Colony observed pairs[72]
----------------------------------------------
Suderoy 73,945 49,500
Lítla Dímun 13,220 8,800
Stóra Dímun 68,050 45,600
Sandoy 101,710 68,100
Hestur 17,290 11,600
Mykines 14,500 9,700
Vágar 4,224 2,800
Streymoy 27,214 18,200
Eysturoy 10,520 7,000
Kalsoy 14,150 9,500
Vidoy 5,980 4,000
Fugloy 22,730 15,200
------- -------
Totals 587,333 393,200[72]
----------------------------------------------
Greenland
Greenland, which has an area of 2,175,600 km² and extends for a
distance of 2,670 km from the northernmost to the southernmost point
of the country, is almost a continent by itself. The range of the
different species of seabirds, therefore, is greatly varied, and it
is necessary to classify them according to the relation between their
distributions and the marine zones. A description of the zones of
the marine environment in the North Atlantic was given by Salomonsen
(1965), and the breeding distributions of seabirds in Greenland
based on this system are given in Table 7. The terrestrial area of
southernmost West Greenland belongs to the subarctic zone of the boreal
province, and one boreal bird species, the black-headed gull, has bred
there in recent years. It is, however, as much a freshwater bird as a
marine one.
Table 7. _Distributions of seabirds breeding in Greenland in
relation to marine zones._
Marine zone and species[73]
Boreo-panarctic
_Fulmarus glacialis_
_Somateria mollissima_
_Stercorarius parasiticus_
_Rissa tridactyla_
_Sterna paradisaea_
_Cepphus grylle_
_Fratercula arctica_
Panarctic
_Larus hyperboreus_
_Uria lomvia_
_Clangula hyemalis_
_Gavia stellata_
High arctic
_Somateria spectabilis_
_Branta bernicla_ _(hrota)_
_Stercorarius longicaudus_
_Xema sabini_
_Larus thayeri_
_Pagophila eburnea_
_Cepphus grylle_ (_mandti_ group)
_Plautus alle_
_Fratercula arctica_ _(naumanni)_
_Phalaropus fulicarius_
Low arctic
_Larus glaucoides_
_Phalaropus lobatus_
Boreo low arctic
_Mergus serrator_
_Phalacrocorax carbo_ _(carbo)_
_Larus marinus_
_Alca torda_
_Uria aalge_
_Cepphus grylle_ (_grylle_ group)
_Fratercula arctica_ _(arctica)_
Boreal
_Larus ridibundus_
[Illustration: Fig. 1. Breeding range in Greenland of four
boreo-panarctic seabirds, _Fulmarus glacialis_, _Somateria mollissima_,
_Rissa tridactyla_, and _Fratercula arctica_.]
[Illustration: Fig. 2. Breeding range in Greenland of three
boreo-panarctic seabirds, _Sterna paradisaea_, _Cepphus grylle_, and
_Stercorarius parasiticus_, and one low arctic species, _Phalaropus
lobatus_.]
[Illustration: Fig. 3. Breeding range in Greenland of three panarctic
seabirds, _Uria lomvia_, _Larus hyperboreus_, and _Clangula hyemalis_,
and one high arctic species, _Stercorarius longicaudus_.]
[Illustration: Fig. 4. Breeding range in Greenland of three boreo-low
arctic seabirds, _Mergus serrator_, _Larus marinus_, and _Phalacrocorax
carbo_, and one high arctic species, _Plautus alle_.]
The widely differing ranges of Greenland seabirds are shown in Figs.
1-4 and are based on my new and previously unpublished data. The
borderline between the high arctic and low arctic zones is situated in
Melville Bay on the west coast, and just south of Scoresby Sound on the
east coast; the innermost parts of Scoresby Sound belong to the low
arctic zone.
In the low arctic Pacific region the number of seabirds is said to be
about 51 million in summer and 8 million in winter (Sowl and Bartonek
1974). No similar estimate is available for low arctic West Greenland,
but I suggest that it is much lower in summer and slightly higher in
winter.
The human population of Greenland, now numbering about 50,000
individuals, is restricted to the seashore, where all cities and
minor outposts are situated. Although shooting seabirds is an ancient
tradition in Greenland, the true land-birds, which are few in number,
are usually left alone. Seabirds collected by shooting provide an
important source of food that the Greenlanders could not do without.
Since special shooting and hunting regulations have not been developed
in Greenland, these activities often resemble a sort of slaughter
rather than true hunting. There is no game act in Greenland, and
practically all birds can be shot. This condition is similar to that
in Canada, where according to Section 5(7) of the Migratory Birds
Regulations (Canadian Wildlife Service, Ottawa 1973) "an Indian or Inuk
may at any time, without a permit, take auks, auklets, guillemots,
murres, puffins and scoters and their eggs for human food and
clothing." Much the same sort of hunting privileges exist for native
peoples of Alaska. What is still worse, however, is the enormous
illegal shooting of ducks, geese, swans, and cranes that is known to
take place in arctic North America, but is largely ignored by police
and game authorities. Bartonek et al. (1971) described this situation
very well for Alaska. In Greenland, it is not possible any more to
distinguish between "native Eskimos" and Greenlanders (including Danes
working in the country), but the attitude toward animals among the
inhabitants is the same as it has always been--a food source to hunt
and kill.
With a rapidly growing human population, and a readily available
supply of guns and speedboats for hunting, the whole natural ecosystem
is beginning to break down, and it cannot be permitted to continue.
The provincial government is aware of this fact, and various legal
enactments have been issued from both the government and the local
magistrates. However, since the size of the police force (mostly
Greenlanders) is small, it is of little help for the preservation of
wildlife, and sometimes even the policemen themselves do not know
the local ordinances. The result has been that seabirds, previously
profusely flourishing, have considerably decreased in number in West
Greenland.
I have previously described the shooting and hunting of seabirds in
Greenland and the statutory provisions issued to protect them (see
Salomonsen 1970). At present, the following seabirds and their eggs
are totally protected: whooper swan; common puffin, _Fratercula
arctica_; and harlequin duck, _Histrionicus histrionicus_. Some other
species have a closed season or are protected in certain parts of the
country: snow goose, _Anser caerulescens_; common eider; king eider,
_Somateria spectabilis_; great cormorant; dovekie, _Plautus alle_;
black guillemot; and thick-billed murre, _Uria lomvia_. Furthermore,
all catching and hunting of birds within 2 km of breeding colonies of
murres and kittiwakes is prohibited. Bird sanctuaries where hunting,
catching, and collecting of eggs and down are prohibited are Avsigsut,
Nunatsiaq, and Satuarssunguit islands, which are scattered in Disko
Bay, and Tasiussarssuaq Fjord (the inner part of Arfersiorfik Fjord,
south of Egedesminde).
However, the Greenland Provincial Council has been alarmed by the
serious decline in the numbers of seabirds due to increases in human
persecution, and it has decided to introduce a game law similar to
those in Denmark and other European countries. The preparation of this
legislation was left to me, and a draft of this Greenland game act has
been issued (Salomonsen 1974); the new law was passed in parliament in
1977 and went into force on 1 January 1978.
It is not possible to review in detail the different parts of the new
law, but certain important points should be mentioned. In northern
parts of West Greenland (north of Egedesminde) the sea is ice-covered
for 7-8 months a year, and seabird hunting is therefore not possible
outside the breeding season. Because of this, it was necessary to allow
some hunting of murres, eiders, and immature gulls during the breeding
period, but away from nesting locations. Consumption of seabirds is to
be limited to local residents, and sales to canneries for shipment to
other cities is to cease. Previously, canneries in northwest Greenland
exported large numbers of thick-billed murres to South Greenland--e.g.,
25,606 birds in 1971; and 30,029 in 1972 (Anonymous 1974:64). This
marketing of murres will end.
Other parts of the proposal important for seabirds include:
• A general closed season extending from 15 June to 15 August.
• Prohibition of shooting at breeding colonies of seabirds, as is in
force at present (cf. above).
• Eggs of terns and gulls can be collected for food in southwest
Greenland to 1 July, and in northwest Greenland to 10 July; fulmar and
murre eggs can also be collected in northwest Greenland.
• Each hunter is allowed to shoot or catch 50 birds per day, but the
entire bag must be used for human consumption.
• All shooting from speedboats, aircraft, and motor vehicles is
prohibited.
• Catching flightless common eiders, king eiders, and oldsquaws
_(Clangula hyemalis)_ is prohibited.
• Practically all seabirds and shorebirds can be shot; all other birds
(except rock ptarmigan and raven) are totally protected.
The principles of this radical new act must be taught to the population
by all possible means of communication, including radio, public
meetings, schools, etc.
* * * * *
Another matter of great concern to seabirds in Greenland is the
Atlantic salmon fishery off the west coast by Danish, Greenlandic
and foreign fishermen. It is well known that many birds are killed
in the fishing gear, and a serious political controversy has arisen,
especially between the governments of the United States and Denmark.
The fact that a large number of thick-billed murres were drowned in
salmon gill nets during their southward swimming migration along the
Greenland coast was significant. In a resolution sent by the XV World
Conference of the International Council for Bird Preservation in Texel
to the Danish Government, it was stated that the annual incidental
drowning of murres probably involved about 250,000 individuals--a
figure exceeding the reproductive capacity of the species. This
estimate was doubted by Danish fishery biologists, but recent
investigations carried out by the Canadian Wildlife Service and the
Fisheries Research Board of Canada have shown that the figure is even
greater, and that the total kill amounts to about half a million murres
annually (Tull et al. 1972).
Because of this mortality of murres, an agreement was reached between
the American and Danish governments, namely that:
From 1 January 1976, all salmon fisheries outside the 12-mile
boundary shall totally stop. In the years 1972-75 the fishery
carried out by Danish and Faroese fishermen shall be reduced
gradually from 800 to 300 tons of fish, and shall terminate on 31
December 1975. The fish quota by Greenland fishermen must amount
to no more than 1,100 tons annually, but from 1976 onwards, the
fishery shall be restricted to areas within the 12-mile limit.
This agreement, which has drastically reduced the number of murres
caught, was discussed at a meeting of the International Committee of
North Atlantic Fisheries in May 1972, and was ratified by the countries
involved in July 1972.
Oil pollution has never occurred in Greenland, but concessions for
offshore oil drilling along the West Greenland coast have just been
granted by the Danish Government, and this new development gives rise
for concern. However, it is clearly stated in the concession that the
Ministry for Greenland can lay down rules for protection against oil
pollution and other damage to human or animal life, and can adopt
measures to fight pollution which has already taken place (section
5(9)). It is up to the concessionary to oversee industrial developments
in the area and see that marine pollution is avoided (section 11).
Toxic chemicals have been found in Greenland seabirds, as everywhere
else in the world, but it must be emphasized that no pesticides
whatsoever are in use in Greenland itself. Investigations by Somer
and Appelquist (1974) indicated that the mercury content in black
guillemots in Greenland has doubled over the last 20 years, and has now
reached 2 ppm, which is, however, a relatively low figure. Levels of
DDE, PCB, and aldrin in Greenland birds were investigated by Braestrup
et al. (1974). Common eider, king eider, harlequin duck, and oldsquaw,
as well as thick-billed murre and great cormorant, were examined; all
were found to be contaminated with pesticides, although to varying
degrees. Highest concentrations occurred in the cormorant, which
contained 6.5-15 ppm of DDE and 14.1-46.7 ppm of PCB. These specific
differences appear to show that the pesticide level in the different
species of seabirds is influenced more by the position of the bird in
the food chain than by its migratory habits.
And finally, I wish to mention a more happy event. On 9 May 1974 a
new law of nature protection in Greenland was passed by the Danish
Parliament. According to this law, a National Park is to be established
covering almost the entire northeast and north regions of Greenland,
from the Thule District in northern West Greenland around the entire
north coast of Greenland and south along the east coast to the northern
inner parts of Scoresby Sound. All hunting, fishing, egg-collecting,
and disturbances to the environment are forbidden in this enormous
area. This is by far the greatest National Park in the world, covering
about 800,000 km². Of this total area, the greater part is a lifeless
icecap, to be sure, but about 200,000 km² is ice-free land and suitable
habitat for numerous high-arctic birds.
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Salomonsen, F. 1963. Oversight over Danmarks fugle. [With
explanatory notes in English.] Munksgaard, Copenhagen. 156 pp.
Salomonsen, F. 1965. The geographical variation of the fulmar
_(Fulmarus glacialis)_ and the zones of marine environment in the
North Atlantic. Auk 82:327-355.
Salomonsen, F. 1968. The moult migration. Wildfowl 19:5-24.
Salomonsen, F. 1970. Birds useful to man in Greenland. Pages
169-175 _in_ Productivity and conservation in northern
circumpolar lands. International Union for Conservation of Nature
and Natural Resources, Morges, Switzerland.
Salomonsen, F. 1974. Forslag til vedtægt om jagt på fuglene i
Grønland. Diskussionsoplæg til kommunalbestyrelserne udarbejdet
på opfordring af Det grønlandske Landsråd. Tidsskr. Grønland
1974(5):155-172.
Somer, E., and H. Appelquist. 1974. Changes and differences in
mercury level in the Baltic and Kattegat compared to the North
Atlantic using _Uria_ sp. (guillemot sp.) and _Cepphus grylle_
(black guillemot) as indicators. 9th Conf. of the Baltic
Oceanographers, Kiel. 12 pp. Danish Isotope Centre, Copenhagen.
Sowl, L. W., and J. C. Bartonek. 1974. Seabirds--Alaska's most
neglected resource. Trans. N. Am. Wildl. Nat. Resour. Conf.
39:117-126.
Strandgaard, H. 1964. The Danish bag record. I. Studies in game
geography based on the Danish bag record for the years 1956-57
and 1957-58. Dan. Rev. Game Biol. 4(2):1-116.
Tull, C. E., P. Germain, and A. W. May. 1972. Mortality of
thick-billed murres in the West Greenland salmon fishery. Nature
(Lond.) 237(5349):42-44.
FOOTNOTES:
[67] Not counted.
[68] No estimate, but number insignificant.
[69] Species totally protected.
[70] _Branta bernicla_ is fully protected since 1972.
[71] _Somateria mollissima_, _Melanitta nigra_, and _M. fusca_.
[72] The "number of pairs" is calculated by multiplying the number of
birds observed by 0.67 (Dyck and Meltofte 1975).
[73] A few species breed near freshwater lakes, but are marine during
the nonbreeding season.
Present Status and Trends in Population of Seabirds in Norway
by
Einar Brun[74]
University of Tromsø
Tromsø, Norway
Abstract
The most numerous seabird in Norway is the
puffin _(Fratercula arctica)_, but its current
breeding population of 1.25 million pairs
is slowly declining. The kittiwake _(Rissa
tridactyla)_, however, is increasing and
establishing new colonies; its population now
stands at 510,000 pairs. The population of
the common murre _(Uria aalge)_, the seabird
species most vulnerable to human activity,
was about 160,000 breeding pairs in 1964 but
is now decreasing at a rate of nearly 5% per
year. Of the other alcids, the razorbill
_(Alca torda)_ and thick-billed murre _(Uria
lomvia)_ show similar declines, and the black
guillemot _(Cepphus grylle)_ is maintaining
a stable population. The fulmar _(Fulmarus
glacialis)_ and the gannet _(Sula bassana)_
have both spread from the British Isles and
have established a number of breeding colonies
in Norway during this century. Evidently
immigration of gannets is still occurring,
since the observed rate of increase far exceeds
the population's intrinsic rate of increase.
The impact of human activity on bird mortality
varies from species to species. The two most
serious factors are coastal oil pollution
and the use of fishing gear; direct hunting
pressure accelerates the decline of murres and
razorbills. Persistent toxic chemicals are not
yet a serious problem in Norway.
Norway, with a coastline of more than 20,000 km, an abundance of
islands, and areas of offshore upwelling, provides good conditions
for a rich seabird fauna. A regional study of this seabird fauna has
been undertaken as a sideline of basic marine research. Although the
ultimate aim has been to evaluate the importance of seabirds in the
energy flow of a marine ecosystem, a more realistic problem (given
priority so far) has been to study yearly production and the dynamics
behind changes in the breeding populations.
Good population estimates are of fundamental importance to studies of
population dynamics. Because the available censuses of seabirds in
Norway were few and largely inadequate, a long-term program was started
in 1961. In the beginning, resources and assistance were very limited,
and the work was concentrated on cliff-breeding seabirds, particularly
the gannet _(Sula bassana)_, fulmar _(Fulmarus glacialis)_, kittiwake
_(Rissa tridactyla)_, razorbill _(Alca torda)_, common murre _(Uria
aalge)_, thick-billed murre _(U. lomvia)_, and puffin _(Fratercula
arctica)_. Until 1970, the study involved making annual censuses in the
approximately 20 major colonies of cliff-breeding seabirds and mapping
the distribution of the quantitatively less important colonies.
Since 1970, the Norwegian seabird program has also involved more
detailed studies in some selected colonies. In these colonies, emphasis
has been on investigation of yearly production and of the factors
limiting this production, and evaluation of the effects of human
activity on the population growth.
Material and Methods
The logistics of census operations have gradually improved from the use
of slow, local transportation to the use of fast pneumatic boats and,
in more recent years, seaplanes. Various census methods have been used,
depending on species and circumstances.
For puffins, a method based on measurement of feeding frequency
and on the number of puffins per time unit that pass a particular
observation post when they return from the feeding ground was used
(Brun 1971_a_). Kittiwakes and gannets were readily censused by a
combination of photographic methods and detailed counts in sample areas
(Brun 1971_b_). Direct counting is by far the most accurate method
for razorbills, murres, and fulmars; but in the larger colonies of
common murre, lack of time permitted accurate counts for only a limited
proportion of the cliff. Direct counts of individuals, the egg/chick
ratio, and estimates of the relative size of the censused population
were used to estimate the total population of the colony.
In a colony of kittiwakes near Tromsø, environmental factors that limit
breeding success, such as temperature and wind exposure, were monitored
throughout the breeding season on a data recorder, and detailed
measurements of temperatures on and inside the eggs have been recorded.
For further information about the influence of environmental parameters
on incubation rhythm and nest attendance, the presence of the male and
female at a particular nest was recorded by using radioactive bands and
a Geiger-Muller tube connected to a pen recorder.
In a study of the effects of human activity, egg samples of selected
species were analyzed for mercury, PCB, and DDT derivates. An effort
was also made to obtain figures for the mortality caused by oil
pollution and fishing gear as well as by direct hunting pressure.
Results
_Status and Trends of Cliff-breeding Species_
Puffin _(Fratercula arctica)_
By far the most numerous seabird in Norway is the puffin (Fig. 1),
which is the only species with a breeding population of more than 1
million breeding pairs (Tables 1, 2). In a 1964 census (Brun 1966) the
total breeding population was put at 1.5 million pairs. The current
figure of 1.25 million pairs includes several newly discovered colonies
and some not censused in 1964; it is more accurate than the previous
census for most of the 15 largest colonies which make up 99.9% of the
total population. The puffin population is concentrated in Troms and
Nordland (94%), with only about 3% in Finnmark.
[Illustration: Fig. 1. Distribution of the puffin _(Fratercula
arctica)_ in Norway. Numbers refer to localities listed in Table 2.]
Kittiwake _(Rissa tridactyla)_
The second most numerous seabird species in Norway is the kittiwake,
which dominates in a number of the larger cliff colonies. Its
distribution pattern differs from that of the puffin--the main
occurrence of the kittiwake population (about 63%) is in Finnmark
(Table 3).
Table 1. _Estimate of the numbers of seabirds breeding on the
coast of Norway 1970-1974. Species are listed in descending order
of breeding population size._
Thousands of Increase (+) or
Species pairs[75] decline (-)
_Fratercula arctica_ 1250 -
_Rissa tridactyla_ 510 +
_Larus argentatus_ (260)[76] +
_L. canus_ (150)[76] +
_Uria aalge_ 100 -
_L. marinus_ (40)[76] +
_Phalacrocorax aristotelis_ 33 +
_Alca torda_ 30 -
_Cepphus grylle_ 22 0
_Sterna paradisaea_ (21)[76] -
_S. hirundo_ (13)[76] -
_Phalacrocorax carbo_ 12 +
_L. fuscus_ 9[76] +
_Stercorarius parasiticus_ (8) 0
_L. ridibundus_ 4[76] +
_Fulmarus glacialis_ 1.1 +
_U. lomvia_ 1.0 -
_Hydrobates pelagicus_ ? ?
_Sula bassana_ 0.76 +
_Oceanodroma leucorrhoa_ ? ?
The annual production of kittiwakes shows enormous variation, both
throughout the coastline and in different years; however, at our sample
stations in north Norway, the mean production in 1974 (Table 4) was
more stable and was near the minimum value necessary to maintain zero
population growth.
This minimum production, mₓ (number of females produced per breeding
female), can be computed from survival rates
mₓ = (1-P)/1ₓ = 0.13/0.57 = 0.23
where P is annual adult survival and 1ₓ is survival of fledged chicks
up to first breeding. Data on survival are taken from Coulson and White
(1959) and from Norwegian banding recoveries.
The kittiwake has, however, established a number of new colonies,
and although the local increase in some of these is spectacular, the
long-term change during the last 15 years is only about 1% increase per
year in northern Norwegian colonies (E. Brun, unpublished data). In
southern Norway, the population has increased much more rapidly (Brun
1971_c_).
Common murre _(Uria aalge)_
The common murre (Fig. 2) has shown a considerable decrease. The most
spectacular decrease is at Sør-Fugløy, where a colony of 10,000 pairs
in 1940 was reduced to 4,000 pairs in 1961, to 1,100 pairs in 1966, and
to only about 10 breeding pairs in 1974 (Table 5). Most of the census
work was done in 1964 and 1974. The general trend in population change,
as expressed by the yearly decrease or increase, has been extrapolated
forward to 1974 or back to 1964 for those colonies where censuses were
missing for either of these years, to enable a better comparison (Table
6). The overall decrease in Norwegian colonies of the common murre is,
thus, near 5% per year; the few cases with a positive trend are based
either on very small figures or on extrapolation from old, inadequate
censuses.
Thick-billed Murre _(Uria lomvia)_
The thick-billed murre (Fig. 3) was first proved to breed in Norwegian
colonies in 1964; it was then found at three localities and has since
been found breeding at eight localities (Table 7). It is now fairly
certain that the thick-billed murre is not a newcomer but has remained
unnoticed among the common murre for generations, possibly since the
original immigration of the _Uria_ species after the last glacial
period. Data are not sufficient to show whether this small population
of thick-billed murres is decreasing at the same rate as the common
murre.
Table 2. _Status of the puffin_ (Fratercula arctica) _in Norway
(cf. Fig. 1)_.
Year of Number of Percent of
Locality census pairs population
1. Kjør 1975 80 <0.1
2. Heglane 1970 4 <0.1
3. Ferkingstadøyene 1970 5 <0.1
4. Utsira 1970 2 <0.1
5. Utvær 1970 200 <0.1
6. Ryggsteinen 1970 2 <0.1
7. Veststeinen 1970 1,500 0.1
8. Einevarden 1970 1,500 0.1
9. Svinøy 1970 100 <0.1
10. Runde 1974 30,000 2.4
11. Saløy 1970 2 0.1
12. Sklinna 1974 2,000 0.2
13. Lovunden 1968 60,000 4.8
14. Fugløy i Gildeskål 1968 800 0.1
15. Røst 1964 700,000 55.7
16. Værøy 1974 70,000 5.6
17. Nykvåg 1967 40,000 3.2
18. Frugga 1975 5,000 0.4
19. Anda 1970 10,000 0.8
20. Bleik 1968 40,000 3.2
21. Sør-Fugløy 1968 40,000 3.2
22. Nord-Fugløy 1967 218,000 17.3
23. Loppa 1968 180 <0.1
24. Hjelmsøy 1964 20,000 1.6
25. Gjesværstappen 1973 18,000 1.4
26. Kongsøy 1966 30 <0.1
27. Syltefjord 1966 100 <0.1
28. Hornøy 1967 160 <0.1
29. Reinøy 1967 40 <0.1
Total 1,257,705 100.0
Razorbill _(Alca torda)_
Another colonial cliff-breeding alcid, the razorbill (Fig. 4), has a
distribution pattern very similar to that of the common murre, but the
individual colonies (Table 8) are, with one exception, smaller. The
total breeding population was estimated at 36,000 pairs in 1966-69
(Brun 1969_b_); some more recent censuses show a definite decline,
but data are not sufficient to estimate the overall decline in the
Norwegian population. At most, the current breeding population is
30,000 pairs.
Fulmar _(Fulmarus glacialis)_
The fulmar is one of two species of seabirds that have spread from
colonies in the British Isles and established themselves as breeding
birds in Norway during this century (the other is the gannet).
[Illustration: =Fig. 2.= Distribution of the common murre _(Uria
aalge)_ in Norway. Numbers refer to localities listed in Tables 5 and
6.]
[Illustration: =Fig. 3.= Distribution of the thick-billed murre _(Uria
lomvia)_ in Norway. Numbers refer to localities listed in Table 7.]
Table 3. _Status of the kittiwake_ (Rissa tridactyla) _in Norway,
and a comparison of distribution with that of the puffin_
(Fratercula arctica).
-------------------------------------------------------------
Breeding pairs
-------------------------------------------
_Rissa_ _Fratercula_
-------------------- --------------------
Number Number
County (thousands) Percent (thousands) Percent
-------------------------------------------------------------
Finnmark 321 62.9 38 3.0
Troms 9 1.8 258 20.5
Nordland 72 14.1 928 73.7
Trøndelag (S, N) 1 0.2 2 0.2
Møre and Romsdal 105 20.6 30 2.4
Sogn and Fjordane 1.9 0.4 3 0.2
Rogaland 0.1 -- <0.1 --
Total 510 100.0 1,259 100.0
-------------------------------------------------------------
The fulmar began nesting in the early 1920's on Runde, the only
sizeable seabird colony in south Norway, off Alesund. Further
immigration of birds from the British Isles probably occurred in the
first 25 years, when the population increased about 10% annually to
about 350 pairs in 1947 (Valeur 1947). Since then the population
increase has slowed down to about 3% annually, and the population on
Runde in 1971 was about 700 pairs (Table 9). From Runde, fulmars have
spread not only to a number of islands in the same region, but also
much farther afield--south to Utsira (59°18'N, 4°55'E) and north to
Bleik (69°3'N, 15°42'E). The total Norwegian population of fulmars in
1971 was estimated at 1,100 pairs.
[Illustration: =Fig. 4.= Distribution of the razorbill _(Alta torda)_
in Norway. Numbers refer to localities listed in Table 8.]
[Illustration: =Fig. 5.= Distribution of the gannet _(Sula bassana)_ in
Norway. Numbers refer to localities listed in Table 10.]
Table 4. _Annual production, mₓ, of the kittiwake_ (Rissa
tridactyla) _at some North Norwegian coastal localities (mₓ =
number of females produced per female)_.
-------------------------------------------
Sample size
Locality Year (number) mₓ
-------------------------------------------
Vedøy, Røst 1972 852 0.21
Hekkingen, Troms 1974 264 0.46
Hjelmsøy 1974 357 0.18
Jarfjord 1974 146 0.31
Total 1,619 0.25
-----------------------------------------
Gannet _(Sula bassana)_
The gannet (Fig. 5), the most recently established and least numerous
of the cliff-breeding seabirds, has the best-known population change.
Like the fulmar, it was established in 1946 on Runde, and the first
individuals were undoubtedly of British origin. During its entire
breeding history on Runde, and also in two of the three new colonies
in northern Norway established in the 1960's, the yearly increase has
far exceeded the intrinsic rate of increase (Table 10); for gannets
with a 50% breeding success, adult mortality of 6%, and 35% survival
up to first breeding, the intrinsic rate of increase is about 2% per
year. The Runde and Syltefjord colonies are naturally protected by
their inaccessibility, but the colonies at Mosken and Nordmjele, which
are on small islets, are both easily accessible. The Nordmjele colony,
however, has been effectively protected from its start, whereas the
Mosken colony has been open to visitors; this difference is probably
reflected in their different breeding success and annual growth rate
(Table 11). The breeding success necessary to maintain a stable
population with the mortality figures given above is 34%:
mₓ = (1-P)/1ₓ = 0.66/0.35 = 0.17
For equal sex ratio, breeding success is 2 times mₓ = 0.34.
A British ringed gannet from Ailsa Craig (55°12'N, 5°07'W) was found
nesting when 4 years old in the Nordmjele colony in 1970 (Brun 1972),
giving direct evidence that immigration from colonies in Great Britain
(Scotland) still takes place.
Table 5. _Status of the common murre_ (Uria aalge) _in Norway
(cf. Fig. 2)_.
Last census Previous census
No. of No. of
breeding breeding
Locality Year pairs Year pairs Reference
1. Utsira 1970 1 1950 10 Holgersen 1951
2. Utvær 1970 17 1948 55 Willgohs 1952
3. Veststeinen 1970 29 1950 40 Willgohs 1952
4. Klovningen 1970 35 1950 20 Willgohs 1952
5. Einevarden 1970 30 1952 25 Willgohs 1955
6. Runde 1974 6,000 1963 7,600 Brun 1969_a_
7. Storholmen 1970 8 -- --
8. Røst 1974 6,800 1964 9,700 Brun 1969_a_
9. Værøy 1974 1,750 1964 2,400 Brun 1969_a_
10. Nykvåg 1974 350 1966 430 Brun 1969_a_
11. Bleik 1974 60 1952 90 Regnell 1957
1964 75 Brun 1969_a_
12. Sør-Fugløy 1974 10 1940 10,000 Soot-Ryen 1941
1961 4,000 Brun 1963
1966 1,100 Brun 1969_a_
13. Nord-Fugløy 1967 9,000 1963 15,000 Lütken 1965
14. Loppa 1974 500 1966 800 Brun 1969_a_
15. Hjelmsøy 1974 70,000 1964 110,000 Brun 1965
1967 95,000 Brun 1969_a_
16. Gjesværstappene 1973 580 1967 750 Brun 1969_a_
17. Sværholtklubben 1973 20 1966 25 Brun 1969_a_
18. Omgangsstauran 1973 70 1967 85 Brun 1969_a_
19. Syltefjorden 1974 9,000 1966 12,300 Brun 1969_a_
20. Hornøy 1974 500 1964 730 Brun 1969_a_
21. Reinøy 1974 110 1964 160 Brun 1969_a_
22. Kjøfjord 1970 21 -- --
23. Skogerøy 1970 8 1967 6 Brun 1969_a_
24. Sagfjord 1970 9 1967 12 Brun 1969_a_
25. Kobbholmfjorden 1970 2 1967 1 Brun 1969_a_
_Estimates of Total Seabird Population in Norway_
In addition to the more detailed censuses of the cliff-breeding species
dealt with so far, notes have been made on all seabirds observed during
numerous flights along the Norwegian coast. Although a first attempt
at putting a figure to all seabird species in Norway may be somewhat
premature, it is believed that even an extrapolation combined with an
educated guess is of some value until more accurate censuses covering
the whole coast can be made. Although the data (Table 1) are arranged
in the same way as the results from "Operation Seafarer" in the British
Isles (Cramp et al. 1974), it must be stressed that the accuracy of the
Norwegian figures, at least for the non-cliff-breeding birds, is far
inferior to the very fine British data. The table includes data for two
petrels (_Hydrobates pelagicus_, _Oceanodroma leucorrhoa_), which in
Norway breed on Røst (well north of the Arctic Circle), where they have
adapted to a delayed breeding season with egg laying in August because
of the conflict of their nocturnal habits with the continuous daylight
due to the midnight sun. Of the present population trends that are
given for each species in Table 1, all auks except the black guillemot
_(Cepphus grylle)_ are decreasing, whereas the gulls, the gannets, and
the fulmars are increasing.
Table 6. _Population trends in colonies of the common murre_
(Uria aalge) _in Norway. Numbers for 1964 and 1974 are, when not
censused those years, extrapolated from present trends, using
estimated yearly decrease or increase from all available census
figures._
Number of Percentage yearly
breeding pairs[77] decrease (-) or
Locality 1964 1974 increase (+)
1. Utsira 2 1 -12.2
2. Utvær 23 14 -5.5
3. Veststeinen 32 27 -1.6
4. Klovningen 30 39 +2.8
5. Einevarden 28 31 +1.0
6. Runde 7,438 _6,000_ -2.2
7. Storholmen 9 7 (-2.2)[b],[c]
8. Røst _9,700_ _6,800_ -3.6
9. Værøy _2,400_ _1,750_ -3.2
10. Nykvåg 453 _350_ -2.6
11. Bleik _75_ _60_ -2.3
12. Sør-Fugløy 1,844 _10_ -68.5
13. Nord-Fugløy 13,201 3,681 -13.6
14. Loppa 900 _500_ -6.1
15. Hjelmsøy _110,000_ _70,000_ -4.6
16. Gjesværstappen 853 556 -4.4
17. Sværholtklubben 27 19 -3.2
18. Omgangsstauran 94 68 -3.3
19. Syltefjorden 13,299 _9,000_ -4.0
20. Hornøy _730_ _500_ -3.9
21. Reinøy _160_ _110_ -3.8
22. Kjøfjord 21 20 (-0.4)[78],[79]
23. Skogerøy 5 12 +10.1
24. Sagfjord 16 6 -10.1
25. Kobbholmfjord 1 5 +26.0
Total 161,341 99,566 -4.9
Table 7. _Status of the thick-billed murre_ (Uria lomvia) _in
Norway (cf. Fig. 3)_.
No. of Percentage of
breeding total _Uria_
Locality Year pairs population
1. Vedøy, Røst 1974 15 0.3
2. Værøy 1966 20 0.9
3. Hjelmsøy 1974 850 1.2
4. Gjesværstappene 1973 25 4.3
5. Syltefjord 1970 90 0.9
6. Hornøy 1966 55 8.1
7. Reinøy 1964 1 0.6
8. Kjøfjord 1970 1 4.8
Estimated number, Norway, 1974 >1,000 ca. 1.0
Table 8. _Status of the razorbill_ (Alca torda) _in Norway (cf.
Fig. 4)_.
--------------------------------------------------
No. of
Locality Year breeding pairs Percent
--------------------------------------------------
1. Kjør 1970 1 <0.1
2. Utsira 1970 25 0.1
3. Utvær 1970 16 0.1
4. Veststeinen 1970 22 0.1
5. Klovningen 1970 12 <0.1
6. Einevarden 1970 45 0.2
7. Runde 1974 2,800 9.5
8. Sklinna 1974 15 0.1
9. Lovunden 1968 8 <0.1
10. Røst 1974 3,900 13.2
11. Værøy 1974 800 2.7
12. Nykvåg 1966 250 0.8
13. Bleik 1968 28 0.1
14. Sør-Fugløy 1974 15 0.1
15. Nord-Fugløy 1967 10,000 33.8
16. Loppa 1969 750 2.5
17. Hjelmsøy 1974 7,000 23.7
18. Gjesvær 1973 2,500 8.5
19. Sværholtklubben 1973 18 0.1
20. Omgangsstauran 1973 6 <0.1
21. Kongsøy 1966 8 <0.1
22. Syltefjorden 1966 1,200 4.1
23. Hornøy 1967 65 0.2
24. Reinøy 1967 55 0.2
25. Kjøfjord 1970 9 <0.1
26. Skogerøy 1970 4 <0.1
27. Jarfjordnes 1970 3 <0.1
Total ca. 30,000
--------------------------------------------------
Since the coastline of Norway is about the same length as the
coastline of Great Britain and Ireland, it is interesting to compare
the population figures (Table 12), although the accuracy is very
different. Populations of auks and gulls are similar in both areas,
but the species composition is different. There are more terns in the
British Isles, but skuas _(Catharacta skua)_, shags _(Phalacrocorax
aristotelis)_, and great cormorants _(P. carbo)_ are present in similar
numbers. The most striking difference is the very small number of
procelli-forms and gannets in Norway compared to Britain and Ireland,
where they are almost as numerous as the gulls and the auks.
Table 9. _Status of the fulmar_ (Fulmarus glacialis) _in Norway_.
---------------------------------------
Number of
Number of breeding
County localities pairs
---------------------------------------
Nordland 6 140
Møre and Romsdal 7 945
Sogn and Fjordane 2 11
Rogaland 2 2
Total 17 1,098
---------------------------------------
Table 10. _Population increase of the gannet_ (Sula bassana) _in
Norway (cf. Fig. 5)_.
----------------------------------------------------------------------------
Mean yearly No. of breeding pairs
Year growth rate ----------------------------------
Colony established 1969-1974 (%) 1969 1970 1971 1972 1973 1974
----------------------------------------------------------------------------
1. Runde 1946 8.4 330 331 383 422 450 494
2. Mosken ca. 1960 5.4 50 83 77 60 62 65
3. Nordmjele 1967 83.3 7 36 65 103 127 145
4. Syltefjord 1961 14.5 28 29 44 48 51 55
Total 12.8 415 479 569 633 690 759
Yearly growth
rate (%) 15.4 18.8 11.2 9.0 10.0
----------------------------------------------------------------------------
Discussion
_Impact of Human Activity_
Direct Exploitation
According to Norwegian laws, all seabirds, with the exception (for some
odd reason) of the gannet and fulmar, can be hunted from 21 August
to 1 March. However, only the two species of murre and the razorbill
are still regularly hunted and, although no statistics support it, an
estimate based on interviews with some of the hunters reveals that
murres and razorbills are shot in the ratio of about 50:1. One man can
shoot as many as 380 murres and razorbills during a winter season as a
sideline to fishing. Although not many hunt on this scale, an absolute
minimum of 5,000 murres and razorbills are killed this way each season.
A new law based on modern principles of conservation has been under
consideration for several years, and this will mean an improvement.
However, the speed of the decline of the auks, particularly the
murres, makes it imperative to stop this hunting immediately, and it
is of very little economic importance to the few who take part. Some
illegal "fishing" for auks still takes place at Røst and Vaerøy, where
fishnets are anchored over wooden frames outside the auk colonies at
the beginning of the nesting season. At Vedøy on Røst in 1972, up to 80
murres were taken daily. Thus an estimated total of 500-700 murres were
taken that year--about 5% of the breeding population on this island.
Egg collecting was important during World War II, but in these more
affluent times and because of the relative inaccessibility of the auks'
nests, egg collecting is now both less attractive and less important.
Human disturbance of the breeding colonies, however, is gradually
becoming a more serious factor.
Table 11. _Comparison of annual growth rate and breeding success
in two colonies of gannets_ (Sula bassana).
----------------------------------------------
Mosken Nordmjele
---------------- ----------------
Annual Breeding Annual Breeding
growth success growth success
rate (%) rate (%)
----------------------------------------------
1969 62 --
1.66 5.14
1970 51 61
0.93 1.81
1971 36 46
0.78 1.58
1972 33 62
1.03 1.23
1973 50 35
1.05 1.14
1974 12 39
1969-1974 1.05 40 1.83 46
----------------------------------------------
Fishing Gear
Although on a scale different from that in western Greenland, drift-net
and longline fishing for Atlantic salmon _(Salmo salar)_ outside the
19-km (12-mile) limit off the northern Norwegian coast present a
serious mortality hazard to some seabirds. Reliable data exist only
for the longline fisheries. In the 1969 season (with 75 effective days
from mid-March to mid-June), one boat using 1,040 hooks per day caught
294 birds: 52 fulmars, 3 gannets, 43 kittiwakes, 107 murres, and 89
puffins. No razorbills were identified, but they may have been included
in the murre figure. If this sample is representative, the 100 or so
Norwegian boats using longlines plus about 20 Danish boats (which used
4,000-6,000 hooks per day and consequently caught more birds) would
have caught roughly 10,000 fulmars, 600 gannets, 9,000 kittiwakes,
21,000 murres, and 18,000 puffins in the 1969 season. The drift-nets in
Norwegian waters are reported to be less damaging to seabirds than are
the longlines, but even without adding the figures from the drift-nets,
the numbers are substantial in view of the size of the Norwegian
breeding populations.
Table 12. _Comparison of the number of seabirds breeding on the
coasts of Great Britain and Ireland (Cramp et al. 1974) and on
the coast of Norway._
Number of breeding pairs[80]
Species Great Britain and Ireland Norway
_Fulmarus glacialis_ 306,000 1,100
_Puffinus puffinus_ > 175,000 --
_Hydrobates pelagicus_ 10⁵ or 10⁶ 10³ or 10⁴
_Oceanodroma leucorrhoa_ 10⁴ 10²
_Sula bassana_ 138,000 760
_Phalacrocorax carbo_ 8,100 12,000
_P. aristotelis_ 31,000 33,000
_Stercorarius skua_ 3,100 1[81]
_S. parasiticus_ 1,100 8,000
_Larus ridibundus_ 74,000 4,000[82]
_L. canus_ 12,000 (150,000)[82]
_L. fuscus_ 47,000 9,000[82]
_L. argentatus_ 333,000 (260,000)[82]
_L. marinus_ 22,000 (40,000)[82]
_Rissa tridactyla_ 470,000 510,000
_Sterna sandvicensis_ 12,000 --
_S. dougalli_ 2,300 --
_S. hirundo_ 14,000 (13,000)[82]
_S. paradisaea_ (31,000) (21,000)[82]
_S. albifrons_ 1,800 --
_Alca torda_ (144,000) 30,000
_Uria aalge_ (577,000) 100,000
_U. lomvia_ -- 1,000
_Cepphus grylle_ 8,300 22,000
_Fratercula arctica_ (490,000) 1,250,000
Total ca. 3,000,000 ca. 2,500,000
Use of fishing gear close inshore, especially pound nets set near
colonies of diving seabirds, can take a heavy toll under special
weather conditions. In 1969 at Runde, 85 birds, mainly auks, shags,
and some diving ducks, were caught in one net in 24 hours; this is
an exceptionally high figure. The total loss of diving seabirds in
pound nets per year in Norway (about 6,000 nets fishing for 40 days)
was estimated to be at least 40,000 birds in 1969. The data are too
unreliable to give species composition, however, since fishermen rarely
make note of this.
Amounts of fish offal from offshore trawlers, drift-netters, and
longline fishing boats have increased in recent years, and some
seabirds, particularly kittiwakes, fulmars, and gannets make use of
this new and readily available food source. Thus, although the use of
fishing gear is a serious threat to seabird survival, fish waste from
the same boats provides an abundant food supply for the more pelagic
species.
Pollution
No quantitative investigation similar to those made in Great Britain,
Netherlands, and Belgium (Tanis and Bruyns 1968) has been carried out
on the impact of oil pollution on seabirds in Norway. The northern
Norwegian population of the most threatened species, murres and
razorbills, winter in North Sea coastal areas where oil pollution and
oiled birds have most frequently been found. It is possible that whole
populations winter every year in the same area, and if they happen to
be in a heavily polluted area, a particular population may be seriously
affected. Such an occurrence is believed to have caused the dramatic
decline in the Sør Fugløy population (cf. Table 5).
Although not yet serious, pollution by persistent toxic chemicals such
as organochlorines and mercury is a problem even in northern Norway,
because the northbound coastal current brings water masses, plankton,
and nekton from areas with industrial wastes. Analysis of the eggs of
herring gull _(Larus argentatus)_, murre, razorbill, and kittiwake in
1972 showed relatively low levels of mercury; the only species with
a relatively high level of mercury (mean 0.58 ppm) was the gannet
(Fimreite et al. 1974). This elevated toxic burden may have caused a
reduced breeding success for the gannet. Analysis of concentrations of
PCB's and DDT/DDE showed that the levels of these organochlorines were
generally also lower in Norwegian seabirds than in those of Britain
(Fimreite et al. 1977).
Protection and Necessary Conservation Measures
Total protection of some of the important seabird colonies (including
the surrounding nearshore waters) has proven very effective, especially
when the protection is so strict that landing is prohibited for a
specified period during incubation and fledging. However, to reduce the
rapid decrease of some species, a total hunting prohibition of those
species must be instigated, oil pollution must be reduced, and the
fisheries must be regulated to reduce the mortality caused by fishing
gear.
_Natural Factors Influencing Breeding Success_
The factors discussed so far are all results of human activities which
directly or indirectly influence seabird mortality. Yearly production
or breeding success is, however, also influenced by a number of
natural factors such as food supply, availability of suitable nest
sites, predation, climate (weather), and population-dependent factors
(age, breeding experience, population density). For the gannet, whose
breeding success has been studied in some detail (Brun 1974), it was
concluded that the differences in exposure (to severe weather) and in
breeding experience were the most important factors responsible for
annual fluctuation in breeding success. For such species as murres,
razorbills, and puffins, food supply is an important limiting factor.
If the spawning of the fish species that constitute their main food
items fails 1 year for some reason, it may be very difficult for the
seabirds to find an adequate alternative food supply and most of the
chicks starve to death. To a lesser degree, food supply is limiting
for the kittiwake, which seems to be more influenced by bad weather
(Norderhaug et al. 1977).
Conclusion
Two opposite population trends have been observed--the decline of the
coastal-bound murres and razorbills and the increase and spread of
the more pelagic gannets, fulmars, and kittiwakes. These changes are
attributed to a number of factors, which include the following:
• The diving murres and razorbills spend a major part of their time
swimming on the surface and are thus more susceptible to surface oil
pollution than are the pelagic species.
• The coastal-bound murres and razorbills are quite heavily hunted,
whereas there is no regular hunting of the pelagic species.
• The pelagic species are mainly surface feeders and do not swim under
water, and are thus less affected by the drift-nets than are diving
birds.
• The pelagic species are the principal beneficiaries of recently
increased supply of fish offal from trawlers.
Acknowledgments
The program was originally sponsored by Tromsø Museum, later University
of Tromsø, and has been financially supported by the Norwegian Research
Council for Science and Humanities and the Norwegian Game Fund. The
research grants are gratefully acknowledged. I also thank my field
assistants and the many local people at the breeding sites who have
been most helpful.
References
Brun, E. 1963. Ornithological features of Nord-Fugløy and
Sør-Fugløy. Astarte 1(22):1-13.
Brun, E. 1965. Brunnich's Guillemot, _Uria lomvia_ (L.), as a
breeding bird in Norway. (In Norwegian, English summary.) Sterna
6:229-250.
Brun, E. 1966. The breeding population of puffins _(Fratercula
arctica)_ in Norway. (In Norwegian, English summary.) Sterna
7:1-17.
Brun, E. 1969_a_. The breeding distribution and population of
guillemots _(Uria aalge)_ in Norway. (In Norwegian, English
summary.) Sterna 8:209-224.
Brun, E. 1969_b_. The breeding distribution and population of
razorbills _(Alca torda)_ in Norway. (In Norwegian, English
summary.) Sterna 8:345-359.
Brun, E. 1971_a_. Census of Puffins _(Fratercula arctica)_ on
Nord-Fugløy, Troms. Astarte 4:41-45.
Brun, E. 1971_b_. Breeding distribution and population of
cliff-breeding seabirds in Sør-Varanger, north Norway. Astarte
4:53-60.
Brun, E. 1971_c_. Population changes of some seabirds in south
Norway. (In Norwegian, English summary.) Sterna 10:35-56.
Brun, E. 1972. Establishment and population increase of the gannet
_Sula bassana_ in Norway. Ornis Scand. 3:27-38.
Brun, E. 1974. Breeding success of gannets _Sula bassana_ at
Nordmjele, Andøya, north Norway. Astarte 7:77-89.
Coulson, J. C., and E. White. 1959. The post-fledging mortality of
the kittiwake. Bird Study 6:97-102.
Cramp, S., W. R. P. Bourne, and D. Saunders. 1974. The seabirds of
Britain and Ireland. Collins, London. 287 pp.
Fimreite, N., J. E. Bjerk, N. Kveseth, and E. Brun. 1977. DDE and
PCBs in eggs of Norwegian seabirds. Astarte 10:15-20.
Fimreite, N., E. Brun, A. Frøslie, P. Frederichsen, and N.
Gundersen. 1974. Mercury in eggs of Norwegian seabirds. Astarte
7:71-75.
Holgersen, H. 1951. Investigations of seabirds in Rogaland
1949-1950. (In Norwegian, English summary.) Stavanger Mus. Arb.
1950:61-76.
Lütken, E. 1965. The breeding birds on Nord-Fugløy, north Norway,
their distribution and numbers. (In Danish, English summary.)
Dansk Orn. For. Tidsskr. 58:166-193.
Norderhaug, M., E. Brun, and G. U. Møllen. 1977. Barentshavets
sjøfuglressurser. Forhold i tilknytning til status,
miljøproblemer of forshningsoppgave. Medd. Norsk Polar Inst.
104:1-119.
Regnell, S. 1957. Fran det nordnorska fåggelberget Bleiksøya. Fauna
Flora, Upps. 52:199-202.
Soot-Ryen, T. 1941. The seabird rookeries of Troms county. (In
Norwegian, English summary.) Tromsø Mus. Aarsh. 62(1):1-112.
Tanis, J. J. C., and M. F. M. Bruyns. 1968. The impact of oil
pollution on seabirds in Europe. Proc. Int. Conf. Oil Pollution
of the Sea 1968:67-74.
Valeur, P. 1947. Havhesten og havsula på Rundøy. Naturen 70:370-379.
Willgohs, J. F. 1952. On the distribution of some seabirds in
western Norway. Univ. Bergen Årb. 1951 Naturvit. Rekke (9):1-20.
Willgohs, J. F. 1955. Om forekomsten av endel kyst-og sjøfugl på
Vestlandet. Fauna, Oslo 8:16-27.
FOOTNOTES:
[74] Deceased.
[75] Numbers in parentheses are not based on a complete census of the
coast.
[76] In addition, an unknown number of pairs breeding inland.
[77] Numbers in italics were censused from 1964 and 1974.
[78] Estimated values from trends in neighboring colonies.
[79] Numbers in parentheses are not based on a complete census of the
whole coast.
[80] Numbers in parentheses are not based on a complete census of the
whole coast.
[81] New in 1975 (Wim Vader, personal communication).
[82] In addition, an unknown number of pairs breeding inland.
SYMPOSIUM SUMMARY
Conservation of Marine Birds of Northern North America--A Summary
by
Ian C. T. Nisbet
Massachusetts Audubon Society
Lincoln, Massachusetts 01773
This is not going to be a straightforward summary of the conference
because it is my view that a number of important topics have not been
addressed. In particular, what was supposed to be the main theme of the
conference--the need for _conservation_ of marine birds of northern
North America--has been taken for granted by many speakers and has
been treated by others in what may be a misleadingly brief way. So
instead of simply summarizing the information that has been presented
in the papers, I want to give my own views about how we should use
this information to make a case for the conservation of marine birds.
I feel strongly that we can make a good case for conserving them, and
that we know enough to start doing so. The task of making a case for
conservation and of proposing priorities for action has been left to me
as the conference summarizer.
Particularly in the first half of this conference, we heard a long
series of accounts of the birds of the area which stressed our
ignorance--large amounts of information that was not known and large
amounts of research that needed to be done. Now, I have an unexpected
advantage over most of these speakers in that I have very little direct
experience in the area. What I learned from their papers, not having
any very clear picture of the islands, the birds, their habits, or
the food that they eat, is that we already know quite a lot about the
marine birds of northern North America. We certainly know enough to
decide what we ought to do next and how to take the basic steps in
conserving them.
After listening to the presentations, reading the abstracts, and
studying the maps posted in the conference hall, I drew up a list of 10
points that I will first list and then elaborate on.
• We know that we are discussing a very important biological resource
which has been neglected for a long time.
• We know roughly what this resource consists of and which aspects of
it are biologically important.
• We know why this resource is in its present condition, and we know
something about the ways in which it is related to other resources.
• We know a certain number of things that the birds do which make them
vulnerable to changes in the environment.
• We know that the resource has already been disturbed in the past,
both by human-induced and by natural changes, and we know that it has
already been damaged.
• We can identify at least some of the major threats that the resource
will face in the next few years.
• We know that the resource can be conserved, at least to a modest and
partial extent.
• We have a fairly good idea of what we ought to do now to start
conserving the resource.
• We have some ideas--so far rather rough and ill-formulated--about why
we should conserve the resource.
• We know--or so I believe--that it is practicable and economically
feasible to conserve the resource.
I am sure that there will be some disagreements with some of these
assertions, especially with the last two, so I will give reasons why I
believe that we should conserve these birds and that we can afford to
do so.
Magnitude and Importance of the Resource
The papers in the first half of the conference which reviewed the
abundance and distribution of the birds in the northern North Pacific
Ocean, the Bering Sea, and adjacent seas suggested that we are dealing
with numbers of birds of the order of 100 million. That is 100 million
birds at sea plus some unknown number of millions of birds along the
shore. We do not have to take these numbers literally--I am sure
that the persons who produced them did not mean them to be taken
literally--but certainly we are talking about something on the order of
tens of millions and not much more than some hundreds of millions. At
least, it is on the order of a hundred million rather than ten million
or a billion. I do not think it an exaggeration to say that this is one
of the great neglected biological resources of the world.
Characteristics of the Resource
Three important aspects of this resource have not been identified
clearly in the papers delivered at the conference, in part because the
papers summarizing the biological surveys did not include much of the
detail that was available in the maps posted in the conference hall.
[Maps in this volume do not show the detail of those posted.] These are
the numerical abundance of the birds, their diversity, and their unique
characteristics.
As to abundance, figures have been mentioned on the order of 50 million
for shearwaters (_Puffinus_ spp.) and 25 million for murres (_Uria_
spp.). For other species the quoted numbers have been less specific,
but I would estimate from what I have read and heard that the total
population must run into millions for eiders (_Somateria_ spp.),
kittiwakes _(Rissea brevirostris)_, and fulmars _(Fulmarus glacialis)_,
and doubtless for other species. The numbers of the smaller alcids, in
particular, must be very great.
As to diversity, there is an impressive number of species and a wide
variety of habitats. We have been shown in the photographs some
spectacular island colonies, particularly in the Bering Sea and the
Aleutian Islands, some of which have a remarkable variety of species.
Several different definitions of "seabird" have been used at this
conference, but certainly there are dozens, and probably scores, of
genuine marine species that either breed in the area or use it as a
major nonbreeding area. The collection of birds in the area of the
North Pacific and the Bering seas seems more impressive in terms of
both abundance and diversity than anything in the north Atlantic Ocean,
which has been so much more fully studied.
As to the uniqueness, there has been almost no mention of the endemic
species at the conference. It is therefore important to emphasize
in this summary that a significant group of marine or coastal
birds is endemic to this area. These birds include the red-legged
kittiwake (_Rissa_ spp.), the Aleutian tern _(Sterna aleutica)_, the
spectacled eider _(Somateria fischeri)_, the emperor goose _(Philacte
canagica)_, and the red-faced cormorant _(Phalacrocorax urile)_; a
number of alcids, including the whiskered _(Aethia pygmaea)_, parakeet
_(Cyclorrhynchus psittacula)_, crested _(A. cristatella)_, and least
auklets _(A. pusilla)_; the horned puffin _(Fratercula corniculata)_;
and Kittlitz's murrelet _(Brachyramphus brevirostris)_. In addition, we
should not forget some migrants that make exclusive use of this area
in their nonbreeding season. These include the short-tailed albatross
_(Diomedea albatrus)_, the scaled petrel _(Pterodroma inexpectata)_,
and I believe also Cook's petrel _(P. cookii)_, which has not
previously been mentioned. From the little we know about its off-season
distribution, the short-tailed albatross appears to use these waters
exclusively; hence it has as much claim to be regarded as an endangered
species of the United States as the whooping crane _(Grus americana)_.
Perusal of the lists of species presented at the conference brings out
one important point. Although we are meeting in the United States and
have been looking at the birds from a United States-Canadian viewpoint,
this is truly an international resource in almost every respect that I
have mentioned. The most abundant species, in terms of both numbers and
biomass, is probably the short-tailed shearwater, a migrant from the
southern hemisphere. The rarest species, and the most endangered, is
the short-tailed albatross, which breeds only on one island in Japan.
There are migrants in large numbers from Chile, Australia, New Zealand,
and especially the Soviet Union. All of these use the area of ocean
and shallow sea that we have been considering as a major area for a
substantial part of their annual cycle.
What more do we need to know about the extent of this resource? In my
opinion we should not place high priority on determining the exact
numbers of the birds--whether there are 25 million or 26 million
murres, for example. It would be difficult, if not impossible, to
determine such numbers in the kind of geographical and climatic area we
are considering. Moreover, even if we were to measure the populations
with great accuracy and to determine in a few years that they had
changed by 10%, we would not be able to draw any conclusions about the
reasons for the change or what should be done about it.
To set priorities for further exploration, I think it is more important
to survey in greater detail the general distribution of the breeding
colonies. So far, we know the location of only the largest colonies;
we know almost nothing about the colonies of a mere 10,000 pairs or
less. So I think future surveys should concentrate on locating the
medium-sized colonies and getting some impression of roughly how many
smaller colonies there are. It is important to locate and be sure that
we know of all the major colonies that have a considerable number of
species; these large, diverse colonies should be given priority for
conservation. Most important of all, we need to locate and survey the
endemic species with some precision. This need is especially great for
the species that we suspect are limited to small areas or that may
otherwise be particularly vulnerable.
If we are to measure population changes over the next few decades, it
is of course essential to have a good base-line survey. However, I do
not think it is either practicable or desirable to try to inventory
the entire population of breeding seabirds with great accuracy. A
more realistic and worthwhile program would be to select some sample
colonies and to catalogue these sample areas in some detail, preferably
with a photographic record, so that they can be resurveyed in later
years to determine whether substantial population changes have taken
place. Criteria for selection of sample colonies for inclusion in this
base-line survey should include not only numerical size and species
diversity but also ease of access, ease of observation, and the
practicability of obtaining good photographic records.
Ecology and Functioning of the Resource
In the opening session of this conference, several speakers reviewed
our general knowledge of the ecology of seabirds; others summarized
our specific knowledge of the birds of the North Pacific, Bering, and
adjacent seas, and their relation to physical and biological factors
in the environment. There is no need to summarize these reviews again
here except to point out that information on the relation between the
birds and the marine environment is being generated very rapidly. We
are beginning to understand the factors that control the breeding
distribution of the individual species, their foraging strategies, and
their dispersion at sea, at least in summer. However, it is clear from
what has been said at this conference that we know much less about
their ecology and distribution in winter. This lack of information
is important because conflicting opinions have been expressed as to
whether factors operating in the winter range or at the breeding
colonies are more critical in limiting population size.
It is evident from what was said in the opening session that the
distribution of the birds is very closely related to the distribution
of marine resources. It is clearly no accident that the distribution
of large numbers of many species of birds coincides with that of the
major fisheries. Similarly, it is no accident that there is a relation
between the distribution of birds and the extent of the continental
shelf. These coincidences, which reflect the fundamental dependence
of both birds and fish upon marine productivity, set the stage for
existing and further conflicts between conservation of the birds and
human exploitation of other resources of the area.
Perhaps the most significant gap in our knowledge of North Pacific
seabirds is in the area of productivity and demography. As far as
I can judge, we know almost nothing about the breeding success of
these birds, their post-fledging survival, their longevity, their
age at first breeding, the age structure of their populations, the
fluctuations in their breeding performance, or their survival from year
to year. For most species, we lack even the most basic life history and
life table information.
If we can argue by analogy from studies made in other parts of
the world, including the North Atlantic, we can make some basic
generalizations that we would expect to apply to the birds of our area.
We know that as a class seabirds have some peculiar characteristics
which make them difficult to manage and cause some of the problems we
have in conserving them. In general, they are long-lived and breed
slowly, most lay small clutches, and the historical experience is that
they take a very long time to recover from depletion of population.
Many have an irregular breeding performance; some have long series of
bad years interspersed with occasional years of good breeding success.
Many seabird populations have traditionally fluctuated, as exemplified
by those of the North Atlantic, whose fluctuations were described by W.
H. Drury and W. R. P. Bourne.
Some species of seabirds are conservative, staying in the same colonies
for many years or generations. Others are volatile, dispersing freely
from one site to another and forming new colonies in an unpredictable
way. Seabirds exhibit a wide range of ecological adaptations; some are
highly specialized, others are highly generalized and adaptable. These
differences can be very important when their environment changes, as
D. N. Nettleship's film "Puffins, predators, and pirates" graphically
illustrated.
As M. T. Myres pointed out on the 1st day of the conference, seabird
populations exhibit both short-and long-term fluctuations. Long-term
fluctuations are those that take place over times comparable to the
generation time of the species, which may be many years or even decades
for some seabirds. By surveying populations and measuring changes in
them, we usually obtain information only about long-term population
trends, reflecting long-term changes in the environment. Short-term
perturbations in the environment are usually not reflected quickly
by changes in total population--certainly not by changes that we can
measure with the accuracy of our present-day census techniques. Many of
the man-made changes we are concerned about are short-term. To identify
their effects we should look not for changes in total population but
rather for changes in biological parameters, such as the first-year
survival rate or the number of young raised. I therefore suggest that
some of the most critical parameters to be measured are changes in age
structure of populations. We should therefore select as biological
monitors species that can readily be aged--for example, gulls, which
have a sequence of distinguishable immature plumages.
In specifying gaps in our knowledge of the ecology of birds, we should
set clear priorities rather than compile a long "shopping list" of
research projects. On the basis of the foregoing survey, I would
suggest the following as priority items for further study. First, we
need to know a lot more about winter distribution, not only of the
marine birds, but also of inshore and coastal species. Second, we
need to study in greater detail the relation between the day-to-day
distribution of birds and the local patchiness of the resources on
which they depend. Evidence that seabirds are able to locate and
use fluctuating and shifting food sources has been given by several
speakers at the conference. We need to understand how birds locate
these resources and what relation this has to their survival and
vulnerability to human activities. There is a special need to study the
ecology of endemic species because their conservation is of special
importance. We need to learn more about the relation of the birds to
the commercial fisheries, both to resolve existing or alleged conflicts
and to avert future problems.
However, I believe that the highest research priority should be given
to obtaining basic information on reproductive success and life table
data for some representative species. Clearly, we cannot study many
species in detail, but in selecting key species for such studies we
should pick a variety of ecological types--for example, at least one
generalist species and one specialist, one sedentary species and one
migrant, one species at a high trophic level and one at a low trophic
level.
For the purpose for which we convened this symposium--conservation--I
do not think that we need detailed knowledge of the factors which
regulate populations. Such knowledge is, of course, of immense
biological interest and will ultimately be needed for effective
long-term management. However, it does not have immediate or even
medium-term relevance to the urgent problems of conservation that we
now face. What we do need to do is to set up some long-term studies of
a few carefully selected species--preferably long-lived species--so
that we can trace the effect of environmental fluctuations on their
performance for a long period.
Vulnerability of the Resource
We already understand a number of factors that make some of these bird
populations particularly vulnerable to the kind of human activities
which we can envisage in the next decade or two. Most of the breeding
birds concentrate on islands where they are vulnerable to predators
and to human disturbance. Many of them concentrate in flocks on human
fishing grounds and over other areas of the continental shelf which
are likely to be the focus of human activity in the near future.
In particular, some of the birds are known to concentrate in the
passes through the Aleutian Islands, where they will be particularly
vulnerable to future oil spills. In all these ways the birds are
concentrated in areas where they are likely to receive disproportionate
impacts from human activity and exploitation.
One point that has been barely mentioned in this symposium is the
effect of molting on the vulnerability of some of these populations.
The eiders, for example, concentrate on molting grounds in the Arctic.
The exact location of these molting grounds may not be fully known,
but we certainly know that the birds molt somewhere in an area where
they will be vulnerable to oil spills (and also to human hunting if
the people who move to the Arctic choose to hunt them). Nor are eiders
the only species that are flightless when they molt. Some alcids and
loons are also flightless for short periods and, hence, particularly
vulnerable to oil spills during molt.
Past Damage to the Resource
In the speech opening the symposium, Assistant Secretary Reed referred
to this biological resource as still relatively unspoiled. While
"relatively" may be an appropriate word, we do have spectacular
evidence of changes and damage to these bird populations. The use of
the Aleutian Islands for fox farming seems to me a quite horrifying
situation. We know also that the early whalers and sealers exploited
seabird populations. Although I know of little specific information
about the effects of such exploitation on birds in the northern North
Pacific, D. G. Ainley in his survey of historical records from the
Farallon Islands has shown very clearly the massive effects of human
exploitation of birds, starting early in the 19th century. In our area
of discussion alone, one species (the spectacled cormorant) is extinct
and another (the short-tailed albatross) became virtually extinct and
is still very rare. I believe that one or two southern hemisphere
species, which must have been substantial elements in the northern
summer bird population, have also been seriously depleted as a result
of human activity on their breeding grounds.
Several speakers emphasized the importance of long-term fluctuations
in bird populations resulting from natural causes, including some
examples from the North Pacific. Other types of human activity must
also have had some indirect effects on the birds. For example, whaling
and sealing in the 19th century must have provided large amounts of
food for scavenging birds and eliminated important competitors for the
larger fish-eating birds. A similar experiment is now in progress as
the predatory fish are being overfished.
Major Threats to the Bird Populations
We now know enough about the distribution and ecology of the seabirds
to identify the major threats to them that are likely to be posed by
the projected increase in human activity in the coming decades. The
relative importance of these threats clearly varies from species to
species and from area to area. However, I think that few of us would
disagree that the largest single threat in the area as a whole is posed
by oil, not only by the prospect of large-scale drilling for oil on
the Alaskan continental shelf but also by prospective spills during
transportation and deliberate dumping from ships.
My guess is that the second most important threat to the seabirds of
the northern North Pacific is the presence of introduced predators,
especially foxes and rats, at the breeding colonies. Much of the damage
inflicted by these predators may already have been done, but I think
their continuing presence is likely to have as great a negative effect
on the bird populations as anything else discussed at the conference.
The relative importance of the other identifiable threats to the birds
is even more conjectural. Drowning of diving birds in fishnets is
obviously of great potential impact, but its importance depends greatly
on the rapidly changing practices of fishermen. This problem must be
kept under close surveillance, and the establishment and enforcement of
international agreements will be critical.
Mineral development has not been mentioned much. It is my understanding
that there are prospects for substantial onshore, and perhaps offshore,
developments of heavy metal minerals. These are likely to lead to local
disturbance in the coastal zone, and the tailings in particular may
well pose a threat to coastal and inshore birds.
Ocean dumping has not been mentioned. I do not expect that there will
be much dumping of toxic chemicals from Alaskan industries, but we
must remember that this area is downstream from Japan and the Soviet
Union. I do not know the current practices of these countries, but the
unregulated dumping of toxic substances from some European countries
apparently has led to large-scale pollution problems in the North
Atlantic.
On present evidence, persistent pesticides and polychlorinated
biphenyls (PCB's) do not seem to pose a significant threat to north
Pacific seabirds, although high levels of PCB's have been reported in
shearwaters off the California coast. In my judgment, we have probably
turned the corner in regulating these chemicals, at least in the
northern hemisphere, and their impact will probably not be allowed to
get worse.
Human disturbance is obviously going to get very much worse, both
from the influx of new human populations who will be involved in more
industrialized activities in Alaska and from the likely increase in
tourism. A matter of particular concern is the prospective influx of
natural history tours, which can have major adverse effects if not
carefully regulated.
Finally, we should not forget the impact of natural phenomena,
including climatic changes and vulcanism. Bearing in mind the
experience of Katmai, we might expect a natural disaster to strike a
major bird colony at any moment.
Practicability of Conservation
Experience from other countries, as related in various papers at this
conference, has shown that conservation of seabirds is possible and
practicable, even in remote and inaccessible areas. We have heard today
particularly about conservation programs and achievements in Europe
and New Zealand. W. H. Drury spoke briefly about experience in eastern
North America and F. Salomonsen told us how the bird populations of the
Faeroes Islands have been managed for sustained yield.
At least in the North Atlantic, where the history of the bird
populations is much better known, the conservation situation has been,
and probably still is, very much worse than that now prevailing in the
North Pacific. Looking back on 200 years in the North Atlantic, we find
that two major marine species have been extinguished, at least one and
probably two or three others became endangered, and almost all the
seabirds were drastically reduced in numbers (at least in temperate
latitudes). Starting in the late 19th century when many species first
received effective protection, most showed impressive recoveries, but
some have declined again in the last 30 years.
We can learn several lessons from that experience. One is that we
can do great damage to seabird populations in a very short time if
we do things that cause substantial adult mortality. A second is
that seabird populations can recover well with protection and modest
management--although most of them, being slow breeders, recover slowly.
A third lesson is that in the last 30 years we have caused substantial
damage through oil spills, human disturbance at the breeding colonies,
chemical pollution, and indirectly by promoting the spread of gulls.
Much has been said at the conference about these present-day human
impacts. However, with the sole exception of the oil spills which have
affected alcids and sea ducks in parts of northwest Europe, it seems
to me that the damage caused by human activity in the past 30 years is
considerably less than that in the last 30 years of the 19th century.
Another lesson we can learn from the recent experience in other
areas is that it is possible to ameliorate some of these adverse
human impacts with local, small-scale, and even rather amateurish
management activities--for example, protecting seabird colonies from
gulls, regulating human visits, and controlling the use of the most
toxic chemicals. Our most conspicuous failure is in controlling oil
pollution. Although safety precautions imposed on offshore drilling
rigs and at shipping terminals have proved reasonably effective in
averting major damage to seabirds, attempts to control oil pollution
during transportation have been essentially fruitless. Tanker accidents
and deliberate discharges from vessels remain the major threat to
seabird populations.
Another lesson from other areas is that public education has been
very effective in putting pressure behind conservation measures, and
is doing so increasingly. At the same time, however, it is resulting
in an increase of the disturbances that the birds suffer at their
breeding grounds from casual visitors, photographers, and sometimes,
well-meaning naturalists.
Finally, in very recent years, there have been encouraging developments
in rehabilitating oiled birds, captive breeding, and reintroduction
into areas from which they have been depleted. Restoration of seabird
populations no longer seems an impossible goal.
Conservation Needs for North Pacific Seabirds
We now know enough about the seabirds of the northern North Pacific
to specify in principle what should be done immediately to conserve
them. I will not address the institutional arrangements needed for
conservation; R. E. LeResche's paper presented a very clear picture of
the institutional problems involved in protecting and managing seabirds
on an interregional and international basis. I will simply endorse
his principal recommendation: that we should try to bring the various
responsible agencies together to formulate comprehensive management
plans.
On the level at which we as individuals and as a group of biologists
can work, we can already make some positive recommendations. The most
important is that since prevention of damage is a lot better than cure,
measures to avert damage should have the highest priority. We have
heard a great deal from the oil industry about the "inevitability" of
accidents. One speaker mentioned the "inherent fallibility of man."
Well, we are all fallible, but the experience of the last 50 years is
that some people are more fallible than others. No oil company has a
perfect record, but some have 10 times as many accidents as the best,
and some, I believe, have considerably more than 10 times as many. This
means, very simply, that it is possible to eliminate most--not all,
but most--of the major threats to the seabirds, merely by upgrading
the safety performance of the entire industry to that already achieved
by its best segments. I suggest that our major challenge in the coming
years is to work for effective regulation of the industry: to achieve
regulations which will decisively penalize bad performance and as
decisively reward care.
Perhaps the second priority in conservation is to protect and manage
the existing breeding colonies. In most cases protection is legally
feasible if we have the will. Most of the major colonies are in
remote areas or in public ownership where development and disturbance
can be controlled. Management of the breeding populations is less
straightforward, however, because we do not know enough about the
functioning of this complex biological resource. Seabird populations
fluctuate and they have a very long response time, the environment
is not constant, we do not understand the dynamics of multispecies
communities, and we do not know how they respond either to external
changes or to our attempts to manage them. Management will have to be
improvisatory for a very long time. We must recognize that effective
conservation of a bird population with a 20-year generation time will
take at least 20 years to show results.
Another priority task is to control predators. I have been impressed
by the evidence we have for major effects of predators on the seabird
populations here. I would regard control of predators and management of
habitats on some of the major seabird islands as an extremely urgent
task.
A longer-term but no less important program is public education. This
program has several important aspects: one is to increase public
support for political actions and effective regulations to protect
seabirds; another is to educate the public about the vulnerability of
seabirds and to prevent disturbance or deliberate human destruction.
Another aspect of public education is to develop public interest
by making some of the birds more visible. The great problem with
this biological resource we have been talking about is that no one
knows it is there. Probably half of us did not know how substantial
and important a resource it is even 5 years ago. In setting up a
large-scale conservation program, we should not make the mistake of
basing it only on the most remote and inaccessible colonies, even
if these are the most important numerically. Many of the smaller
colonies are locally very important, both biologically and for human
interest and education. One example given at this conference was the
State of Washington's program for conserving what are, by northern
Pacific standards, quite small colonies. This program is important
and impressive because it is conserving bird populations near people
who want to see the birds. We have the same sort of situation in
Massachusetts and Maine, where effective protection programs have been
established for extremely small seabird colonies. We have learned
from these programs that a few hundred birds, or even a few dozen if
properly managed, can be of immense educational importance. If human
access is carefully managed so that people can see the birds without
disturbing them, these programs can generate support for conservation
of larger bird populations that may be thousands of miles away where
people may never see them.
A Rationale for Conservation
As I have tried to show, we know something about the importance of
this biological resource, and we know in outline what we should do
to conserve it. But why should we? Almost no one knows the birds are
there. We ourselves do not know whether there are 50 million or 250
million birds in the north Pacific Ocean. Who cares if 10 million
disappear? If we cannot give a good answer to this question, we might
as well go home and study chickadees instead.
To justify spending money on conserving marine birds--or any other
natural resources--we must establish their value. Some of the arguments
made in this conference for assigning economic values to seabirds have
been dangerously weak. The annual value of "muttonbirds" _(Puffinus
tenuirostris)_ in the New Zealand markets is about $70,000. Some
speakers have tried to argue that seabirds might play some subtle role
that we do not yet understand in regulating marine communities--perhaps
they weed out the sick fish. The direct economic values that we have
specified for seabirds are really not very impressive, even in terms of
the costs involved in conserving and studying them. The biggest number
we have heard for the value of these seabirds is the amount of money we
are spending on surveys.
However, this is not the real issue. In judging the costs and benefits
of a conservation program, we should not look just at the value of the
birds as meat, or oil, or indicators of pollution. The real issue here,
as in all economic problems, is the rational allocation of resources.
H. Boyd posed the rhetorical question: "Why should we waste public
money on conserving birds when there are so many other things to spend
it on?" The question is more properly posed in reverse: "Why should the
government waste so much public money on unproductive projects when
only a small amount of money can achieve conservation of these birds
which some people think are important?"
The fact is that we already know why we should allocate resources to
conservation. I believe that we have just been evading the answer.
We ought to conserve these birds because many people want them to be
conserved.
This is not, as one speaker said, an elite interest. The public, as
we well know, is already willing to spend money to conserve natural
resources and is increasingly demonstrating that willingness. The
public, in fact, is ahead of the administrators and bureaucrats. To
appreciate this, we need only look at some of the laws already on the
books. The Congress of the United States, in the National Environmental
Policy Act of 1969, declared that it was the national policy to
"create and maintain conditions under which man and nature can exist
in productive harmony, and fulfill the social, economic, and other
requirements of present and future generations of Americans." The
Marine Mammal Protection Act of 1972 found that "marine mammals have
proven themselves to be resources of great international significance,
esthetic and recreational as well as economic, and it is the sense of
Congress that they should be protected and encouraged to the greatest
extent feasible commensurate with sound policies of resource management
and that the primary object of their management should be to maintain
the health and stability of the marine ecosystem." As these laws have
been enacted, their language has become progressively stronger. The
Endangered Species Act of 1973 declares as the policy of Congress "that
all federal departments and agencies shall seek to conserve endangered
species and threatened species and shall use their authorities in
furtherance of the purposes of this Act" (P.L. 93-205). It further
directs all Federal departments and agencies to carry out conservation
programs for the conservation of endangered or threatened species and
to insure that their actions do not jeopardize the continued existence
of these species or destroy or modify critical habitat.
These references are not only to Federal laws passed by remote
politicians who can vote with only a modest responsibility to their
constituents. As we have heard, there are many State laws and local
ordinances which specify the same kind of thing. All these laws are on
the books for a powerful reason: public opinion was behind them. The
fact that they have not been enforced and implemented fully means that
we have not been doing our job.
In fact, there is no philosophical problem in justifying conservation.
What we face is an institutional problem. There is both a public
determination that natural resources should be conserved and a public
apathy and bureaucratic resistance toward doing it. As concerned
biologists, we should be combating this apathy by pointing out that
conservation represents a rational allocation of public resources.
Those who do not learn the lessons of history are destined to repeat
it. If we study the history of conservation, we find that it developed
most rapidly in those countries which mismanaged their natural
resources earliest. Within the developed countries there has been a
progressive historical trend toward rational use and conservation
of natural resources. Conservation of natural resources, in fact,
represents the future and, as biologists, it is our duty to promote it.
Economic Feasibility of Conservation
Conservation is cheap. Most of us are accustomed to working on what
are essentially shoestring budgets--on the order of $100,000, $10,000,
or even $1,000 per year. When we hear of a million dollars as the cost
of doing something, we tend to think of it as a lot of money. H. Boyd
mentioned a situation on Baffin Island, where it would cost about a
million dollars to dispose of mine tailings on shore instead of dumping
them into the ocean under a fulmar colony. I do not think a million
dollars is very much--certainly not in comparison with the cost of
restoring a colony of half a million fulmars.
We heard this morning about the acquisition of Protection Island at
a cost of several hundred thousand dollars. It was pointed out that
it could have been acquired much more cheaply only a few years ago.
Acquisition of habitat is cheap if we do it now compared with what it
will cost in a few years or a few decades. Management is cheap. None of
us gets paid very much, but each of us could manage several colonies
with a couple of students to help us. Wardens are cheap. Surveys are
cheap. The cost of conserving seabirds is minuscule in comparison with
the amount spent on the exploitation of resources that threatens them,
and it is minuscule in relation to the cost of restoring a seabird
population after it has been depleted.
It is far cheaper to avoid oiling birds than it is to rehabilitate
them and to reestablish them in breeding colonies in the wild. It
costs nothing at all to award leases to companies that have a good
safety record and to refuse leases to companies with bad records. It
costs a little more to maintain good safety practices in drilling
and transportation. It does cost more to transport oil in small,
double-bottomed tankers with well-trained crews than to transport it
in big ships flying flags of convenience, but the cost differential is
very small compared to the value of the shipment.
In considering the economics of conservation, we have to weigh
the costs of conservation against the value of the resource being
exploited. Full-scale development of oil reserves on the Alaskan
continental shelf would generate economic values on the order of
ten billion dollars per year. Of this total, 0.1% would support a
reasonably sized management program for the threatened resources. About
1% of the total, or 12¢ per barrel of oil, would not only support an
ample management program but also permit management of many other
coastal zone resources. Yet the experience of the last few years
has shown that an increase in oil prices of 1% is barely noticed by
consumers.
The point I am trying to make is that extracting oil carefully does not
cost significantly more than extracting it carelessly. If we can solve
the institutional problems--and I do not underestimate the difficulty
of doing so--we are not talking about an irrational use of resources.
Conservation is feasible; it is worthwhile; it is not expensive; and
there is a public demand for it.
Conclusions
Practical conservation is an adaptive process. It is not at present a
process that is firmly based in ecological theory. It is one in which
we have to start by doing something, see whether it works, and then
change our program in accordance with our early experience. I do not
believe that we can wait for detailed knowledge of population sizes, or
ecology, or demography, or trophic importance, or any other biological
attribute of these birds before we start conservation and management.
As scientists we do, of course, find it interesting and important to
study these things. We should do so; we need to do so; but we should
not use our ignorance of detail as an excuse for delaying action. If
this seabird resource is worth conserving, we should start now.
Summary
The marine birds of the northern North Pacific Ocean, Bering Sea,
and adjacent seas constitute one of the great neglected biological
resources of the world.
This resource is impressive in terms of both total numbers (probably
of the order of 100 million birds) and species diversity. A number of
species are endemic to the area and hence of special interest.
The resource is international in that it includes major populations of
migrants from Chile, New Zealand, Australia, Japan, the Soviet Union,
and other countries. Several migrant species appear to use this area
exclusively in their nonbreeding season and should be included in the
list of endemics.
The general relation between the distribution and abundance of seabirds
and other marine resources is beginning to be understood. However,
comparatively little is known about the distribution of seabirds in
winter, and there is a serious dearth of information about breeding
success, survival, and demography.
Seabirds in the north Pacific Ocean and adjacent seas are concentrated
over the continental shelf and in areas of high biological
productivity. Hence they are especially vulnerable to human
exploitation.
Seabirds of the northern Pacific Ocean have already been damaged by
human activities in the past and present. Experience in other areas
shows that seabirds are extremely vulnerable to human activities and
their populations are often very slow to recover.
The most important threats to the seabird resource are oil drilling
and transportation and introduced predators, especially foxes. Other
identifiable threats include mineral exploitation, fishing, ocean
dumping of toxic chemicals, and human disturbance, including both
hunting and tourism.
Experience in other parts of the world, especially in the North
Atlantic, has shown that seabird populations can be protected and
restored through modest programs of management and public education.
The principal exception has been the failure to regulate discharges of
oil at sea, which continue to cause major damage to seabird populations
in many areas.
In the North Pacific and Bering Sea areas, the most urgent conservation
needs are effective regulation of prospective oil exploitation, control
of introduced predators, and public education. Regional management
plans should be developed. Public access to bird colonies should be
managed carefully to combine protection with public education.
Conservation programs for seabirds can be justified as a response to
increasing public demand for rational management of natural resources.
Conservation programs are inexpensive in relation to the economic
values generated by oil and mineral development. They represent a
rational allocation of economic resources.
The following priorities for further study are suggested:
• Study of productivity and demography in a few carefully selected
species to provide basic life table data that will permit rapid
identification of future changes.
• A base-line census of some carefully selected breeding colonies,
including precise photographic surveys that can be used to measure
future population changes.
• Surveys of the distribution of seabirds of the North Pacific and
Bering Sea in winter, with special emphasis on areas close to shore
where birds may be vulnerable to oil pollution.
• Special studies of endemic species.
• Studies of the way in which seabirds locate and use patchily
distributed food resources.
The following conservation measures are suggested:
• Adoption of regulations governing exploitation and transportation
of oil which would provide strong incentives for safe performance and
severe penalties for safety violations.
• A conservation tax of a few cents per barrel of oil to cover the
costs of managing the major seabird colonies and to establish a trust
fund for restoring depleted populations.
• Equivalent measures for mining and other exploitative industries in
the coastal zone with a prospective impact on marine resources.
• Prohibition of dumping of toxic chemicals in biologically productive
waters.
• A program to eliminate introduced predators from the Aleutian Islands
and from important bird colonies elsewhere.
• Promulgation of effective regulations to protect birds under the
Migratory Bird Treaty with Japan.
• Negotiation of migratory bird treaties with other affected countries,
including the Soviet Union, Australia, New Zealand, and Chile.
• Acquisition of major unprotected seabird colonies into the national
wildlife refuge or other federal landholding systems.
• Formulation of regional and international management plans for
localized species, especially endemic species of the Bering Sea.
• Regulation of public access to major seabird colonies.
APPENDIX
Papers and Oral Summaries Presented at the Symposium but Which Do Not
Appear in this Publication
Conservation of marine birds of northern North America--the
symposium theme, by Nathaniel P. Reed
The marine environment of birds: an overview, by N. Philip Ashmole
Environmental hazards to birds from petroleum development in the
Beaufort Sea, by Kees Vermeer [in lieu of a paper on the status
of birds in the Beaufort Sea]
Birds of the marine habitat off northwestern North America, by
Gerald A. Sanger and James G. King
The pelagic and nearshore birds of the Beaufort and Chukchi Seas,
by George J. Divoky and George E. Watson
Dispersal and migratory movements, by George E. Watson, George M.
Jonkel, and F. Graham Cooch
Summary of the session "Status of Marine Bird Populations," by
David N. Nettleship
Breeding habitat of marine birds, by Gerald A. Bertrand
Exposure of marine birds to environmental pollutants, by Harry M.
Ohlendorf, Robert W. Risebrough, and Kees Vermeer[83]
Summary of the session "The Biology and Ecology of Marine Birds in
the North," by Hugh Boyd
Summary of the session "Conflicts Between the Conservation of
Marine Birds and Uses of Other Resources," by Joseph P. Linduska
Programs and authorities of the United States Government related to
marine bird conservation, by Omar Halvorson
Programs and authorities related to marine bird conservation:
Canadian Government, by Hugh Boyd
Programs and authorities of the State of Alaska related to marine
bird conservation, by Robert E. LeResche
Seabird programs of private organizations, by C. Eugene Knoder
Summary of the session "Programs and Authorities Related to Marine
Bird Conservation," by William H. Drury
Conservation of marine birds in Antarctica, by William J. L. Sladen
Seabirds and their conservation in Western Europe, by W. R. P.
Bourne
Summary of the session, "Conservation of Marine Birds in Other
Lands," by Joseph J. Hickey
FOOTNOTES:
[83] This paper, because of its length, was published separately as
_Wildlife Research Report 9_.
U.S. GOVERNMENT PRINTING OFFICE: 1979-681-016/29
TRANSCRIBER'S NOTES
P. 228 the sentence "The factors in Table are largely
self-explanatory" was missing the table reference.
Silently corrected simple spelling, grammar, and typographical
errors.
Retained anachronistic and non-standard spellings as printed.
Enclosed italics markup in _underscores_.
Enclosed bold markup in =equals=.