RESULTS OF THE EXPEDITION. 
161 
altitude of 18,000 feet above the sea level, opposes no 
invincible obstacle to the periodical migration of even the 
tiniest and most feeble- winged of our songsters. 
It is startling to think of birds like the Phylloscopi, ill 
adapted as they seem for lengthened flights, and, when not 
migrating, rarely flying more than a few yards at a time, 
yearly travelling from Yarkand to Southern India and back 
again. How these butterfly-like mites brave in safety 
the vast stretches of almost Arctic deserts — absolutely 
devoid of vegetation, where the thermometer habitually 
varies 50° in twelve hours, and a breeze springing up sends 
the mercui'y down far below zero and freezes men, horses, 
and even yaks, it is alleged, in a few hours, is verily a 
mystery. Some may, perhaps, incline to believe that these 
little tree-warblers do not make this arduous migration, and 
that these vast mountain ranges, doubtless of geologically 
recent elevation, only assumed their present dimensions 
subsequent to the creation or specialization of these species ; 
but although no specimen of these was actually caught in 
the act of migration, I do not think, considering the 
number of species that were thus observed, as also that 
Reguloides proregulus and other equally feeble birds do 
almost certainly make this same and even a longer journey, 
that this explanation can be accepted. I think, moreover, 
that in the Podoces and other species we have indications 
of the lapse of a quite sufficient period since the isolation 
of Central Asia to render probable a marked modification of 
all pre-existing forms which have since continued to reside 
there as permanent inhabitants ; and if these Phylloscopi 
did not yearly cross and recross the Hills, I doubt much 
whether the species found on both sides would now be 
identical. 
Of the Common Quail a few breed within our limits, and 
of the Common Starling many breed in Kashmir ; but these 
are wholly inadequate to account for the incalculable 
myriads of these species which periodically visit us, and 
of these it is now probable that Yarkand furnishes us with 
a large quota. The Quail captured on the 24th September 
in an utterly exhausted state at the Karatag Lake, at an 
M 
