36 
INSESSORES. 
from home, and then quietly dropping an egg into 
their nests. Half-a-dozen of these eggs may be found 
sometimes in a single morning’s walk, by examining the 
newly made nests of the Yellow-poll Warbler, White- 
eyed Yireo, Blue-grey Fly-catcher, Golden-crowned 
Thrush, and Maryland Yellow-throat • the latter more 
especially seeming to he the favorite recipient of this 
unwelcome gift. It is a fact worthy of remark, that, 
although the Cow-bird is much larger than most of 
these birds, yet its egg is quite small, and approaches 
very near to the size of those in the nest where it is 
laid • it also, in almost every case, is hatched several 
days in advance of the others, thus securing to the 
young Cow-bird the exclusive care of its foster-mother. 
Her own eggs soon becoming worthless for want of 
attention, are tossed from the nest to make room for 
the fast-growing intruder, toward which she is as 
devoted in her attentions as though it was her own 
progeny. 
As these birds do not pair, their life must neces- 
sarily be very different from that of others. While 
all around them are in the settled enjoyment of their 
mated companionship, the Cow-birds are roaming 
about the country in small companies, mingling pro- 
miscuously with each other, and seeming to have no 
particular preference for any stated locality. Early 
in the autumn the young birds instinctively join the 
old ones, when they assemble in flocks of immense 
size, and may be seen by the thousands and tens of 
thousands among the reeds along the river banks, 
