The Progress., 1892-06-11
BIRDS ON THEIR TRAvEJ
Every Spring They Come, Every Autumn
They Go.

instinct must be great diffculty
20 the materialist; one of the grhatest
WIN "Alch II mas 10 contend. Whence
is it; asks the Sunday Magazine. The
secret tuition which directs the beaver
to construct its dam the soui4rel n
'aE up q hidden stores. the spi der to
sp'A 49, 9lheh "eo; the guiding i'm
puise when IN the latter days of the
dying year takes from us half our
fcaihered friends. and brings 10 us
in their place host of their hardiey
IeiowS' we have the facts Every
spring they come, every autumn they
go. And as they arrive they meet
others leaving, and as they leave they
meet those others returning-a double
ebb and flow Of feathered life. And
surely enough Of interest attaches to
these periodical migrations without
the need for prying into questions
which we shall never be able to an
swer and discussing problems which
no finite mind can solve. And. after
all we 90 not know the two great
causes which act as the principa.
factors N turning birds twice
year INTO feathered pilgrims.
One cauS is climate, the other
cause is fO'd- A bird like the field
fare. although harder than its first
cousin, the,hrush is nevertheless IN
able to beat the rigors of a northern
winter, andso travels southwark as
soon as tn leaves begin to fall.
Sometimes cen our winter is too Sc
we're for constitution, and then it
travels farthr still and spends Just a
few days wit US on its return journey
in the spring The swift on the other
hand a uatiV OF Northern Africa. can
not endure tn neat Of tropical sum-
mer and so les away uorthward in
time TO escap the pItiless scorchlng
of an almost quatorial sun. Proba-
bly, no bird Is sensitive to extremes
OF heat and CO. 1t leaves its home
to avoid the hda and yet suffers terri
bly, if the air e chill in the land of
its temporary so0ura. Often ard often
have swifts beeip :. cd up dying and
dead in the LAT vs. of an English
spring, chilled Tough and through
by biting nortlriy wind, or frozen
by the cold bias hich comes with
the hail of a verr thunder storm.
The question offood, of course is
dependent upon til of climate. Au-
tumn f. Is begin nd the insects dis |
appear. and so theirds which prey
upon those insects q perforce obliged |
TO depart. driven nee not only by
stress OF weather also by want of |
food. But again aiough our Brit |
ish islands can not pply the swal- |
low, andnthe swift d the nightjar
with the insects weh they need |
they can supply the sdwing and the |
fieldfare with worms d snails and |
slugs, and hips and avs. And so
we extend hospitalitAs it were. to |
one class of birds althgh compelled |
to refuse it to sanotherand the au-
tumnal exodus is balans by tho ALL
tumnal immigration.
Much the same orders preserved !
by these travelling blrdso 9th in their
arrival and departure. The chif-
chat and the willow wsler ("hay-
bird" the rustics call hinare gener-
ally the first to come anasually the
last to go. Sometimes olsees them
even in the gusty days OF .rch, and |
they linger on until the fl frosts of
autumn bring down the la remain
ing leaves from the trees. ,se upon
them follows the active lii sand
martin, bound for the SD soft
walled quarries wherein it 1 scoop
out its odd little burrows W little
exertion. and not much fearf mo-
lestation. Then one notices house
martin or two pioneers OF ! host
which will appear few daYater;
and athen the fsrk-tailed SLOWS