New-York tribune., 1906-12-23
MIGRATION OF BIRDS.
Their Sense of Locality Vel De-
UeIoged.


The migratiop ~ h>ds is a subject which is
full OF inte-esta.g and difficult problems and
not the least interesting nor the least difficult
of comprehension Is the question how they find
their way. About the admirable accuracy Of
their movements there is no question whatever.
The willow warbler will come back year after
year to occupy the same position. in the same
tangle Of grass and underground as the site for
its nest. Others are no less accurate and punct-
ual; but the exactness Of this little bird is the
more remarkable because OF its apparently
feeble powers Of flight, which seem TO leave It
quite unprOvided with the locomotive means re-
qutred to bring IT so unerringly TO its goal While
the questions which migration presents diff
cult enough OF understanding. there is one which
transcends all the rest In it's obscurity. 1t is
the question which is suggested by the fact,
apparently quite well authenticated. that in the
case Of many species they are the young bids
or the year that lead the migration flight. OF
course this is the kind Of fact which is very
say: How do you know that there are not
few old BIRDS perhaps the barren birds Of the
year taking part in the earliest migration flights
or the species, and so giving lead TO the young
steTs along line which has become familiar to
them through previous travel?" It is difficult TO
answer this objector satisfactorily, because he
at once puts his opponent into the position of
one who has to prove negative. and We all
know what an uncomfortable position that is
The pros and OF the whole argument are
tar too long and intricate to enter into here.
All we can do is to ask the reader to accept the
more that the birds of the year in many cases
do lead the migration flight, that some instinct
acts as their compass and that they do not avail
birds
No doubt to ask credence for such a state
nent is to ask good deal. The explanation
inherited instinct along the migration lines fol-
lowed by their forefathers, in some cases pur-
suing the course OF loug-since submerged river
or other visible guiding line, Is an explanation
almost as hard Of acceptance as the original
mystery (which II is invoked to explain. Nor
does the mystery become any less mysterious,
though it becomes more possible Of credence.
even if not of comprehension. when consider
it alongside Of other examples OF like kind with
which natural history can furnish US. For II
does not stand alone by any means If IT did.
we might indeed ask credence for II in vain
The instinct, as IL appears TO be, which leads
animals to direct their course TO q certain spot
without. so far we are able 10 ascertain, any
previous hint or indication of guidance, demon
strates itself in several remarkable ways besides
that of the migration flight, but in none perhaps
more remarkably than in the case Of the guam
AGO. a species of llama OF South America which
resorts in immense numbers to a certain place
70 die. In fact II seems, from the accounts given
by Darwin and by Mr.. W. H. Hudson that all
the guanacoS Of the southern part Of Patagonia
must resort, when the hour OF death approaches.
10 a certain spot in a certain riverbed which
has become a perfect rnausOleum Of their bones.
Mr.. Hudson has haZarded a very ingenious n.y.
pOthesis to account for this assemblage in the
common mOrtuary. He notes. primarily, that It
is only the guanaco Of the southern extremity of
the South American Continent that has this
habit; which IS as much as to say that ii is a
habit restricted to descendants OF forefathers
who lived at one time in an extremely rigorous.
semi-Antarctic climate. Mr. Hudson conJectures
that among these fOrefathers the instinct grew
Tip. when the stress OF hunger and cold was very
dire and they felt its chill setting upon them, OF
resorting to this sheltered place in the river
bed. where they might find warmth in their own
closely collected numbers, and possibly food.
which would enable them to outlive the days Of
extreme rigor. By a continual survival OF those
which betook themselves to this place OF refuge
the race instinct would be formed of resorting
thither when they felt the tides OF life running
low. This feeling, Mr.. Hudson argues. their
descendants are likely 10 experience now at
the approach of the hour of death, and
in obedience to ii to flock to the same
resort But now it is no longer Just
passing spell Of extreme cold which they can
hope to survive that leads them thtther. The
death call has come, and they must lay their
bones in the common mOrtuary. 1t is not 'in
order to die" as frequently say with
very common error in considering the ways Of
animals. that the gUanaco seeks this e; il
would be nearer the truth If we were to say 1t
was ''in order to live But the most true ac-
count OF all no doubt IF the hypothesis Is ac-
Cepted) is that It is with conscious purpose
at all. but IN mere obedience TO the inherited
Instinct that the g,1anaco resorts 10 this refuge:
and still the hypothesis, for all its ingenuity
leaves unanswered the question Csave as IT is
answered by the so-called explanation OF the
migration flight how the guanaco is guided TO
this shelter Of it's forefathers from the Antarctic
cold. Yet another instance OF what appears to
be this wholly mysterious guidance Is Afforded
by the well known habit OF the rattlesnakes. in
the colder countries OF their range. to assemble
together In great numbers for Information In
caves II seems TO be pretty well established
that the snakes. on emerging from these caves
cover long distances in their wanderings; that
their young are generally born far away from
the wintering place, and yet that these young
although they do not accompany their parents
nor remain with them until the date Of hiberna-
ton approaches. still succeed in finding their
way to the caves with the greatest certainly.
All these and many more which might be
cited are instances which tend to show that
animals are led or guided, or whatever the word
may be which Will express most clearly fact
which is really quite obscure, by some force or
influence which is distinct from anything that
our senses reveal 10 US. But 10 say that they
prove # would be to say too much.-The Spec