According to
Azara, this bird, like the cuckoo, deposits its eggs in other
birds' nests. I was several times told by the country people that
there certainly is some bird having this habit; and my assistant in
collecting, who is a very accurate person, found a nest of the
sparrow of this country (Zonotrichia matutina), with one egg in it
larger than the others, and of a different colour and shape. In
North America there is another species of Molothrus (M. pecoris),
which has a similar cuckoo-like habit, and which is most closely
allied in every respect to the species from the Plata, even in such
trifling peculiarities as standing on the backs of cattle; it
differs only in being a little smaller, and in its plumage and eggs
being of a slightly different shade of colour. This close agreement
in structure and habits, in representative species coming from
opposite quarters of a great continent, always strikes one as
interesting, though of common occurrence.
Mr. Swainson has well remarked, that with the exception of the
Molothrus pecoris, to which must be added the M. niger, the cuckoos
are the only birds which can be called truly parasitical; namely,
such as "fasten themselves, as it were, on another living animal,
whose animal heat brings their young into life, whose food they
live upon, and whose death would cause theirs during the period of
infancy.
Pages:
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135