Here is an NSF press release a friend of mine passed along that I thought
might be of interest to some Tweetsters. Jane Hadley

Media Contact:
Cheryl Dybas May 3, 1996
(703) 306-1070 NSF PR 96-19

Program Contact:
Randy Nelson
(703) 306-1419

NEVER THE SAME SONG TWICE FROM SONG SPARROWS

If song sparrows were humans, they would be jazz
singers....and folk singers....and pop singers, says Steve
Nowicki, a National Science Foundation (NSF) grantee who is a
zoologist at Duke University.

Many birds sing songs repeatedly, but with song sparrows,
its not repetition -- its variation. These birds rarely sing
the same thing twice.T

Song sparrows learn as chicks to improvise on old
standards. Not only does this ability set them apart from other
birds, it calls into question basic assumptions about learning,
evolution, and animal communication. SAccording to
neurobiological theory, birds keep songs in a sort of memory
template, says Randy Nelson, director of NSFRs animal behavior
program. Songs stored there can be reeled off at the proper
moment. More complicated songs presumably use more complicated
templates.

Yet nothing in the theory accounts for song sparrowsR
ability to improvise -- or their motivations. As an
evolutionary biologist, I find it interesting because the
different things the birds say don't seem to mean anything
different, says Nowicki. So whats the point of
variation?

The biologist is trying to find out. Nowicki documented
song sparrows variations by making sound recordings in the
Pennsylvania woods and observing how birds behaved as they sang
and listened to one anothers songs. They may be doing it to
prevent habituation, Nowicki suggests. Like a familiar song
with unexpected lyrics (Row, Row, Row Your Canoe, for example
instead of Row, Row, Row your Boat), a bird song may attract
more attention when it is varied.

Another theory has to do with attracting a mate. Darwin
attributed exaggerated male traits, such as peacocks tails, to
their ability to attract females. With more varied songs, song
sparrows may be more successful in wooing mates. To test this
theory, Nowicki plans to play various males recordings to
females. A female signifies when a song has struck a chord by
fluffing up her feathers and preparing to mate. If the theory
is correct, this behavior should occur more often with more
varied songs.

Nowicki is also exploring other explanations, such as
territorial defense, as well as investigating the
neurobiological mechanisms by which song sparrows learn to sing
their varied songs.

-NSF-


NSF was created as an independent federal agency in 1950,
uniquely charged with promoting the progress of all fields of
science and engineering. Today, as a leader and steward of the
nation's science research base, NSF supports both research and
education through competitive grants to about 2,000
universities and other institutions. NSF receives some 60,000
research proposals each year and funds about one-third of them.