Host Nests (Brood Parasites)
Some
birds will lay their eggs in the nests of other birds and pass the
nesting chores to them. For the cowbirds of North America
(especially the Bronzed and Brown-headed Cowbird) this is the only
way they do it. Other species like pheasants and some ducks
may do this occasionally and some females who lose their nest
before they can lay their egg may "dump" their eggs into an active
nest in the neighborhood.
The famous nest parasite of Europe, the
Common Cuckoo, has developed complex strategies for accomplishing
this nesting deception. These cuckoos have developed the
ability to lay their eggs quickly and the egg can sometimes mimic
the egg of the host. The male cuckoo will sometimes lure the
host female from the nest while his mate lays her egg in the
unattended nest and may roll one host eggs out of the nest to
allay suspicion. The whole process take only about 10
seconds.
Note: There are 56 species in the Old World
(Europe, Asia and Africa), but only three species in the Americas
that are obligate brood parasites (always use this nesting
scheme).
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