Bird Dimorphism and Breeding
How can you tell the difference between a female and male
It depends on the kind of bird. Cardinals and gold finches are easy to
tell apart because the boys are very bright and the females have much
duller colors. In other birds, such as male and female sparrows, they
look the same! If you are wondering about specific birds, you can go
to the library and find a bird field guide to help you figure out if
you are looking at a boy or girl, or if it is a species that is hard
to tell apart!
One rule of thumb about dimorphism (male and female have different appearances)
is that if the two species are
different in coloration with the male standing out in some way, then
the male does not share the chore of sitting on the nest; he would
attract predators. Females are usually camouflaged for this reason.
If they are the same in appearance, then both sexes take turns on the
Bright coloration in males tends to indicate that they are aggressive
with nesting territories and will keep members of their same species
away from their declared territory. Other males are less aggressive.
It varies greatly from species to species. Male and female blue jays, for example,
are almost identical, you might be able to tell them apart by careful observation of
behavior. Many birds have some difference in color between sexes, and others, like
many of the ducks, are dramatically different. Field guides will show the differences.
Many raptors (hawks, falcons, and relatives) are different in both plumage and size,
females are usually larger. Immature birds are often quite different in appearance from
adults and it may be harder to tell males and females apart.
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Update: June 2012