The Colorado statesman., 1912-04-20
MIGRATION OF BIRDS.

Where are our summer birds nowI
The ornithologists tell us many In
teresting things about them, but there
are many questions that they are yet
unable to answer.
The cardinal, bobwhite and Caroline
wren do not migrate, but may round
out their lives within a few minutes
OF their birthplaces. The robin is al.
ways with us, but he is not the same
bird in winter as that which visited
In the summer. The bird which
spends its summer In southern Mis-
souri, Will winter near the gulf and
the Canada raised robin will occupy
summer home left vacant.
Some birds, on the contrary, par
tlcularly the eastern nighthawk, trav-
ell immense distances, spending win
ter in Patagonia and summer in Alas
ka. The nighthawk covers from 5000
to 5000 miles each way.
There is much diversity OF opinion
concerning the routes travelled by
birds. Many species which spend
their winters in South America, how.
ever, have a series of natural STEP
ping stones to assist their flight
across the Gulf of Mexico and many
follow their route. BY going this way
the bird need never be out Of sight OF
land. Others go by way of Mexico,
but large number disdain to follow
the land routes and plunge boldly
across the sea, flying out OF sight OF
land long distances and guiding their
flight by some unerring faculty or in
stinct which cannot be understood.
The distance across the gulf traversed
by majority of our birds is more
than 700 miles. The plovers rear
their young near the Arctic circle and
then start south, going out to sea in
the neighborhood of Newfoundland,
and traversing great stretch of the
Atlantic ocean until they arrive at
the Antilles. There they stop a few
weeks and then start over the sea
again, flying southwark. They next
appear in Argentina and range as far
south as Patagonia.
OF course, the plover has the fac
ulty of resting on the waves, so that
the reason 1t does not become ex'
hausted and drown in the sea is ap-
parent. 1t is more wonderful that
the land birds do not become exhaust
ed in their long flight over the Gulf
of Mexico, but observations have
shown that such is not the case, for
land birds arriving at the coast do
not stop to rest until they have
passed fifty or sixty miles inland.
The speed of migrating birds diff
fers, but the generalization can be
made that it is intimately related to
the speed with which the season ad-
vances. The black-poll warbler
traverses most of the United States
from Florida to Minnesota at an aver
age rate of thirty-five miles day, but
when it starts the northern half of its
journey to Alaska, it increases its
speed to an average OF 200 miles
day The reason for this is that the
advance of the seasons is more rapid
beyond the southern boundary OF
Canada.
Much remains to be learned con-
cerning the migration of birds. The
chimney swift disappears somewhere
near the coast of northern South
America, and reappears at the same
place, but it's winter habitat is un'
known. The cliff swallow spends the
winter in Argentina, but instead OF
returning to the United States from
the south, first appears In northern
California. The reason for these
variations from the normal has not
yet been discovered.