LIFE A^'D BEHAVIOR OF THE CUCKOO 
193 
which either bury their eggs like a turtle in the sand, or con- 
struct a kind of "mound-nest" for an incubator, and certain 
cuckoos and cowbirds of both hemispheres, which prey as it w^ere, 
upon the instincts of other birds, the parental impulses have 
become profoundly modified, and diverted into other channels 
and in a peculiar manner. On the other hand the American 
cuckoos follow the usual schedule as completely and with nearly 
the same regularity as the American robin, or any other pas- 
serine bird. 
6. THE NESTS AND EGGS OF AMERICAN CUCKOOS 
Following in a general way the terms of the reproductive cycle, 
outlined in the preceding section, we shall now give an account of 
the behavior of the black-billed cuckoo, particularly of the adult 
in relation to the young, with the addition of such notes on what 
may be called their general habits, as have been observed and 
are worthy of record. 
Migration takes place in April and May, and in the fall in Sep- 
tember and October. The breeding range is very wide, extending 
from at least 35° to 71° north latitude in places, and from the 
eastern slopes of the Rocky Mountains to the Atlantic seaboard. 
These cuckoos migrate at night, possibly the males in advance 
of the females, but this does not seem to have been positively 
determined. The northern tier of States is reached in early May, 
with the main stream of summer resident birds. The call and 
alarm notes of both sexes are similar, though according to some 
acute observers different in the two species, and seem to vary 
considerably in accordance with the distance from the ear, and 
the emotion of the bird which utters them. The loud and often 
prolonged kow-kow-kow-kow note, is the common responsive call 
frequently heard both at and away from the nest, and has given 
origin to the common names of kow-kow, or of rain crow, in 
supposed relation to the weather. It seems to be uttered only 
when the birds are perched, and when heard in early spring, is 
probably the love-call of the male. The birds, though possessing 
a hawk-like profile and appearance, for which their kind has been 
THE JOURN'AL OF EXPERIMENTAL Z05L0GT, VOL. 9, NO. 1. 
