Evening star. [volume] (Washington, D.C.) 1854-1972, 1915-08-01
WAR CLAIMED TO CUT DOWN
DEATH TOLL AMONG birds

those who argue that love Of birthplace
is the actuating impulse to spring migra-
ton call attention to the seeming inn
patience Of the earliest migrants, and to
illustrate this Impotence they use as ex-
amples the ducks and geese which push
northward with the beginning Of open
water SO early, so far and SO fast that
many are caught by late storms and
wander disconsolately over frozen ponds
and rivers. preferring to risk starvation
rather than to retreat. 1t is also pointed
out that the purple martins often arrive
at their nesting boxes SO prematurely
that the coy home becomes tomb il
sleet storm sweeps their winged food from
the air.
The answer to the love of birthplace"
and 'impatence to get home" theory is
that as a matter of fact only a small
percentage of birds exhibit the pre-
seasonal migration propensities. The
great majority. says the bird authority
quoted, remain in the security Of their
homes until spring is SO far advanced
that the journey can be made easily and
with comparatively slight danger; and
they reach the nesting spot when a food
supply is assured and all the conditions
Of weather and vegetation are favorable
for beginning Immediately the rearing Of
a family of young
Another point of opposition to the
theory that longing for home is the main
incentive to the northward flight of birds
is that they desert their homes promptly
after the nesting season is over. Data
collected at the Florida lighthouse by the
biological survey show that southwark
migration begins at least by the 10th, and
probably as early as the LIST Of July. Il
has been observed that most birds start
south as soon as the fiedglings are able
to shift for themselves. The orchard
Ill &l.4 I,&-- -
warbler of central United States and the
nonpareil of the south all begin their
southwark journey early in July. long
before the fall storms sound a warning
OF approaching winter. and when their in
sect menu is particularly varied and
abundant.
One of the curious things in the mi
grafton of American birds is that while
North America possesses enormous
summer supplies of bird food the birds
must return south for the winter or
perish, and while the overcrowding
which would ensue should they remain
in the equatorial regions Is prevented
by the spring exodus northward. no
such movement occurs toward the cor
responding southern ATTITUDES. 1t has
been learned that South America has
almost no migratory land birds, for
bleak Patagonia and TERRA del Fuego
offer no inducements to these jewellers
Of the limitless forests Of the Amazon.
The conclusion reached by Prof.
Cooke is that the advantage OF the
United States and Canada as summer
home. and the superb condition of cli-
mate and food for the successful rear
ing of a nestful of voracious young,
far overbalence the hazards and disas-
tiers of the journey thither. For these
periodical trips did not just happen in
their present form; each migration
route, however long and complex, Is
but the present stage in development
of a flight that was at first short,
easily accomplished and comparative
Iy free from danger. Each lengthening
of the course was adopted permanently
only after experience through many
generations had proved it's advantages.