arasites. The name _Molothrus_ has been
given to the genus that includes the cowbirds. They are confined to
the American continent, having no analogues in the lands across the
seas. The same may be said, indeed, of the whole _Icteridae_ family.
It may be a matter of surprise to many persons that there are twelve
species and subspecies of cowbirds in North and South America, for most
of us are familiar only with the common cowbird (_Molothrus ater_) of
our temperate regions. Of these twelve species only three are to be
found within the limits of the United States, one is a resident of
western Mexico and certain parts of Central America, while the rest
find habitat exclusively in South America. A fresh field of
investigation is open to some enterprising and ambitious naturalist who
wishes to study several of these species, as comparatively little is
known of their habits, and indeed much still remains to be learned of
the whole genus, familiar as one or two of the species are. Their sly,
surreptitious manners render them exceedingly difficult to study at
close range and with anything like satisfactory detail.

Are all of them parasites? Probably they are--at least to a greater or
less degree--except one, the bay-winged cowbird of South America, which
I shall reserve for notice later on in this chapter. We might assert
that our common cowbirds are the parasites _par excellence_ of the
family, for, so far as I can learn from reading and observation, they
never build their own nests or rear their own young, but shift all the
duties of maternity, save the laying of the eggs, upon the shoulders of
other innocent birds.

These avian "spongers" have a wide geographical range, inhabiting the
greater part of the United States and southern Canada, except the
extensive forest regions and some portions of the southern states.
They are most abundant in the states bordering on the upper Mississippi
River and its numerous tributaries. On the Pacific coast west of the
Cascade and Sierra Nevada mountains, they occur only as stragglers.
The most northern point at which they have been known to breed is the
neighborhood of Little Slave Lake in southern Athabaska. In the autumn
the majority of these birds migrate to southern Mexico, although a
considerable number remain in our southern states, and a few
occasionally tarry for the winter even as far north as New England and
southern Michigan.

The male cowbird looks like a well-dr