OF NEW ENGLAND. 247 
the Pewees; also, on the authority of others, the Goldfinches, 
Meadow Larks, and Brown Thrushes. Commonly one egg, 
sometimes two, and rarely three, or even four, are found in the 
chosen nest. I am satisfied, from indirect evidence, that the 
eges are often laid near the nest, if on the ground, and after- 
‘wards placed in it. They are generally laid later than those 
of the rightful owners, though sometimes earlier. The pro- 
prietors, on discovering the intrusion, occasionally destroy the 
foundling, still more rarely build over it a second story, or 
even a third, which becomes the nursery for their own young, 
or, in some cases, even desert their home ; but more often, after 
manifestations of their displeasure, they adopt the helpless 
stranger. As the Cow-bird’s egg is almost invariably some- 
what larger than others in the nest, it receives a larger share 
of warmth, in consequence of which the others frequently 
become stale, when they are removed and destroyed by the 
parents. Even should the legitimate eggs receive an equal 
share of warmth, those of the parasite are first’ hatched, since 
they, in many cases, apparently require a shorter period of 
incubation. Thus the young Cow-bird, who is, as I have once 
or twice observed, hatched in the middle of the nest, is able to 
dislodge his companions, who soon perish, while he grows to 
fill up gradually the space left.86 Carefully nourished and 
brooded over until well grown, and more than old enough to 
provide for himself, he at last leaves his foster-parents, and, 
with a wonderful instinct, searches out and joins his own fel- 
lows and kin. The Cow-birds lay from April until the middle 
of June; each female probably (from analogy) laying four or 
five eggs in one season, and presumably at irregular intervals 
rather than in regular succession from day to day. : 
These birds are gregarious throughout the year. Before 
November they leave Massachusetts, and migrate to the South, 
where they often associate in large numbers with the ‘ Red- 
wings” or other blackbirds. About the first of April, they 
86 As he claims all the time of his foster-mother, her own eggs are often suffered 
to decay before being hatched. 
