164 
ORNITHOLOGY. 
These facts are often explained by the assumption that 
the birds cannot cross the range, but with the experience 
we now have of the manner in which the feeblest species 
traverse the most elevated regions, this explanation can 
scarcely be maintained. In reality I believe that this 
sharp definition of specific range is due to the equally sharp 
definition of climate which is efiected by these great ridges. 
The birds could get over them easily enough, but the moisture- 
laden clouds from the Indian Ocean and the Bay of Bengal 
cannot. Hence south of the range we have a comparatively 
moist climate and more or less heavy periodical rains ; 
while north of it we have an excessively dry climate, varied 
only by occasional showers, or violent but almost rainless 
thunderstorms. South of the range we have luxuriant 
vegetation ; north of it a scanty, stunted flora. There are 
exceptions, but this is the rule ; and to this result of a 
diflPerence in the hydrometric state of the atmosphere, and 
to that difi'erence itself, I attribute the rigid limitation by 
the first high snowy range in the area of distribution of so 
many species. 
Of the great bulk of the species obtained in Ladak, 
Kashmir, and the low hills leading from the plains to 
Kashmir, with whose avi-fauna we are comparatively 
familiar, no detailed notice seems here necessary ; each will 
be separately dealt with in the next chapter. It may not 
be out of place, however, to notice that a Buzzard was 
obtained on the road from Kashmir to the plains, answering 
completely to Hodgson^s and Blyth^s description of Buteo 
aquilinus (and exhibiting in a marked degree the supposed 
specific characteristics of this species, the reticulate scaled 
tarsus feathered for two-thirds of its length) ; which, how- 
ever, after comparison with a vast series of Buteo ferox, I 
believe to belong to that species. The subject is further 
discussed in Chap. II. 
In Kashmir several specimens of a Laughing Thrush were 
obtained, nearly allied to T. variegatum, of which I had 
already received others from the Agrore Valley, and which 
I have now, with much hesitation, separated as T. simile 
[PI. VII.] 
A species of Starling which I long since separated as 
