-AN ORNITHOLOGICAL LECTURE. 95 
scarcity of suitable food, not only for themselves, but also 
for their young; as the food of birds at that time is often 
very different from their ordinary diet, it requires a close 
acquaintance with them to prophesy confidently what birds 
would be likely to be found breeding at a given point. 
But few birds remain in the same region all the year 
round. Out of about two hundred and seventy-five spe- 
cies occurring in New England or New York in June, only 
twenty-five or so stay throughout the year; of these forty 
or fifty come to us in winter only, leaving us two hundred 
and twenty-five species of spring birds, half of which num- 
ber merely pass through to their northern breeding places. 
With this disparity, no wonder that we look for the return 
of the birds, and hail with delight the bluebird calling to us 
through clear March mornings, the velvet-coated robins, the 
battalions of soldierly cedar-birds, the ghostly turtle-doves 
sighing their surging refrain, the pewees, and thrushes, and 
golden orioles, till at last, amid the bursting foliage and 
quickness of May life, a full host of brilliant choristers 
holds jubilee in the sunny tree-tops. | 
In a very few days, as suddenly. and mysteriously as they 
came, half the gay company has passed us, going farther 
north to breed. Could we follow this army, we should find 
it thinning gradually, as one species after another found its 
