MIGRATION OF BIRDS. 291 
must have journeyed down gradually and lingered on the way, 
knowing that it was useless for them to arrive here before the 
conditions were favourable. 
This leads us on to a discussion of the routes by which our 
migrants in general arrive and spread over the Island, and 
also of the times of their arrival and departure. 
Our knowledge of the particular routes used by the various 
species leaves much to be desired, but there are fair general 
indications. We have seen that coast lines and large river 
valleys are favourite fly lines, so it is probable that most of our 
migrants come to us down the Indian Peninsula either by the 
east coast or west coast routes. Birds from Eastern Siberia, 
Mongolia, and the Chinese Empire would come chiefly by the 
former fly line ; birds from Turkestan and Western Siberia 
by the latter. 
We have a very good example of a species which uses the 
east coast routes in the Pintailed Snipe, which, as I have 
mentioned, breeds in Siberia from the Yenesei eastwards to 
the Pacific. During the winter it is very rare in the Punjab 
and North-west Provinces, commoner as one passes east to 
the Ganges delta, while it is the Snipe of Southern India, 
Ceylon, Assam, and further India. It is fairly obvious, then, 
that this species finds its way into India mainly from the 
north-east. Probably its main line of migration lies down 
the valley of the Brahmaputra, and divides when the delta 
is reached, one branch going south-east to Burma, the other 
south-west down the western sides of the Bay of Bengal. 
There may be other crossings over the Eastern Himalayas, 
in which case the birds would make their way to the coast 
down the Ganges valley. Migrant species in general coming 
from Nepaul and the Eastern Himalayas would follow this 
latter fly line. 
There can be little doubt that species, such as the Little 
Stint (Lringa minuta) come to us mainly by the west coast. 
This Stint breeds in Northern Europe and Siberia, and in 
winter is not found east of the Bay of Bengal. Individuals 
from the neighbourhood of the Urals may possibly come 
southwards to the Caspian, then across country to the Persian 
Gulf, and right along the coast line of India to Cape Comorin. 
