Q. How do
birds know which species they are? That is, how do they recognize one another so
they can flock together?
A. Depending on the circumstances,
birds can recognize one another by a complex menu of plumage, shape, behavior
and especially song, but it is not always so important to them to make the call,
said Kevin McGowan, an ornithologist with the Cornell Laboratory of Ornithology
in Ithaca, N.Y.
Some birds that a human could not distinguish by sight as belonging to
different species can recognize one another by subtle differences in song, Mr.
McGowan said, and other species engage in elaborate and distinctive courtship
displays when mating. But for many species, at times it doesn?t matter, he said.
Flocks of ducks or geese can contain members of several distinct species, for
example, and if they are confronted by a predatory hawk or a hunter, they all
take off together.
If an individual bird is lost, Mr. McGowan said, in some species the lost
member ?will make do with something else and hang out with that species.? He
compared the situation to a person walking down a strange street: ?He would
prefer to be with family, but if he recognizes the next best thing, he is happy
to walk along with them.?
But when the time comes for breeding, the individual bird will try hard to
find a member of the same species, through song or strut.
C. CLAIBORNE RAY
http://www.nytimes.com/2009/06/16/science/16qna.html?_r=1&ref=science
