=INTRODUCTION=
Where do the birds go each fall that have nested in our dooryards and
frequented the neighboring woods, hills, and marshes? Will the same
ones return again to their former haunts next spring? What dangers do
they face on their round-trip flight and in their winter homes? These
and other questions on the migratory habits of birds puzzle the minds
of many who are interested in the feathered species, whether it be
the farmer who profits by their tireless warfare against the weed and
insect pests of his crops, the bird student who enjoys an abundance
and variety of feathered inhabitants about him, or the hunter who
wants a continuation from year to year of the sport of wild-fowling.
Lack of information on the subject may mean the loss of an important
resource by unconsciously letting it slip from us. Ignorance of
the facts may be responsible for inadequate legal protection for
such species as may urgently need it. More general knowledge on the
subject will aid in the perpetuation of the various migrants, the
seasonal habitats of some of which are in grave danger from man's
utilization, sometimes unwisely, of the marsh, water, and other areas
they formerly frequented.
The migrations of birds were probably among the first natural
phenomena to attract the attention and intrigue the imagination of
man. Recorded observations on the subject date back nearly 3,000
years, to the times of Hesiod, Homer, Herodotus, Aristotle, and
others. In the Bible are several references to the periodic movements
of birds, as in the book of Job (39:26), where the inquiry is made:
"Doth the hawk fly by Thy wisdom and stretch her wings toward the
south?" Jeremiah (8:7), wrote: "The stork in the heavens knoweth
her appointed time; and the turtle [dove], and the crane, and the
swallow, observe the time of their coming." And the flight of quail
that saved the Israelites from starvation in their wanderings in the
wilderness of Sinai is now recognized as a vast movement of migratory
quail (_Coturnix coturnix_) between their breeding grounds and their
winter home in Africa.
Throughout the ages the return flights of migratory birds have been
important (1) as a source of food after a lean winter, and (2) as the
harbinger of a change in season. The arrival of certain species has
been heralded with appropriate ceremonies in many lands, and among
Eskimo and other tribes the phenomenon to this day is the accepted
sign of the imminence of spring and of warmer weather. The pioneer
fur traders in Alaska and Canada offered rewards to the Indian or
Eskimo who saw the first goose of the spring, and all joined in
jubilant welcome to the newcomer.
Always hunted for food, the large flocks of ducks and geese became
objects of the enthusiastic attention of an increasing army of
sportsmen as the North American Continent became ever more thickly
settled. Most of the nongame species were found to be valuable also
as allies of the farmer in his never-ending warfare against weed
and insect pests. The need for laws protecting the valuable game
and nongame birds and for regulated hunting of the diminishing game
species followed as a natural course. In the management of this
wildlife resource it has become obvious that continuous studies
must be made of the food habits of the various species, their
environmental needs, and their travels. Hence bird investigations
are made by the Biological Survey, the Bureau charged by Congress
under the Migratory Bird Treaty Act with the duty of protecting those
species that in their yearly journeys pass back and forth between the
United States and Canada.
For half a century the Biological Survey has been collecting data on
the interesting and important phenomenon of the migration of North
American birds. The field men of the Bureau have gathered information
concerning the distribution and seasonal movements of the different
species in many extended areas, from the Arctic coast south to the
pampas of Argentina. Supplementing these investigations is the work
of hundreds of volunteer ornithologists and bird students throughout
the United States and Canada, who each year, spring and fall, forward
to the Bureau reports on migrations observed in their respective
localities. Added, to the mass of data thus assembled is a rapidly
growing file of records of birds that have been banded and of the
subsequent recovery of the marked individuals.
These data, together with other carded records gleaned by the
Biological Survey from a vast literature, constitute a series of
files that now contain well over 2,500,000 entries, easily the
greatest existing accumulation of information pertaining to the
distribution and movements of North American birds. Not only do the
facts thus assembled form the basis of regulatory action for the
protection of the birds, but they also make it possible to publish
scientific accounts of the ranges and migrations of the different
species. They furnish the basis of this publication.
The several important bird-protective measures adopted by State and
Federal Governments, particularly those having as their objective the
conservation of the migratory song, insectivorous, and game species,
can be effective only if they have intelligent public support. To
increase such support, information must be more generally available
on that little understood but universally fascinating subject of bird
migration. A brief presentation of facts on the migratory habits
of the birds, scientifically gathered by the Bureau of Biological
Survey over many years, will be helpful to bird-study classes, to
conservation organizations, and to farmers and others individually
interested in the welfare of the birds.
=THE MYSTERY OF MIGRATION=