The Milan exchange. (Milan, Gibson County, Tenn.) 1874-1978, 1880-11-11
Bird MigratiOn---A Geological Puzzle.

| Familiar as this migration of birds is
to us, there is perhaps no question in
zoology more obscure. The long flights
they take, and the unerring certainty
with which they wing their way between
the most distant places, arriving and
departing at the same period year after
year, are points in the history of birds
of passage as mysterious as they are in
! teresting. We know that most migrants
fly after shutdown, though many OF them
select a moonlight night to cross the
| Mediterranean. But that their meteOro-
/ logical instinct is not unerring is proved
by the fact that thousands are every
year drowned in their flight over the
Atlantic and other oceans. Northern
Africa and Western Asia are selected
as winter quarters by most of them, and
they may be often noticed on their way
thither to hang over towns at night,
puzzled, in spite of their experience, by
the shifting lights of the streets and
houses. The swallow or the nightingale
may sometimes be delayed by unex-
pected circumstances. Yet it is rarely
that they arrive or depart many days
sooner or later, one year with another.
Professor Newton considered that were
seafowl satellites revolving round the
earth their arrival could hardly be more
surely calculated by an astronomer.
Foul weather or fair, heat or cold, the
puffins repair to some of their stations
punctuallv on given day. as if their
movements were regulated by clock
work. The swiftness of flight which
characterizes most birds enables them
to cover vast space in brief time.
The common black swift can fly 276
miles an hour, speed which, if it
could be maintained for less than
half a day, would carry the bird
from its winter to its summer quarters.
The large purple swift of America is
capable of even greater feats on the
wing. The chimney-swallow is slower
ninety miles per hour being about the
limit of its powers; but the passenger
pigeon of the United States can accom-
plish a journey of 1000 miles between
sunrise and sunset. 1t is also true, as
the ingenious Herr Palmer has attempt
ed to show, that migrants during their
long flights may be directed by an ex-
perience partly inherited and partly ac-
quired by the individual bird. They
often follow the coast lines of CONT
nents, and invariably take, on their
passage over the Mediterranean, one of
three routes. But this theory will not
explain how they pilot themselves across
broad oceans, and is inyalidated by the
fact, familiar to every ornithologist, that
the old and young birds do not journey
in company. Invariably, the young
broods travel together; then comes,
after an interval, the parents, and,
finally the rear is brought up by the
weekly, infrln, moping and broken
winged. This is the rule in autumn.
The return journey is accomplished in
the reverse order. The distance trav-
eled seems, moreover, to have no rela-
ton to the size of the traveller. The
Swedish blue-throat performs its ma
ternal functions among the Laps and
enjoys its winter holiday among the ne
groes of the Soudan, while the tiny,
ruby-throated humming- bird proceeds
annually from Mexico to Newfoundland
and back again, though one would i'm
agine that so delicate a little fairy would
be more at home among the cacti and
agaves of the TERRA Caliente than
among the frs and fogs of the North
London Standard.