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A researcher at the Museum of Natural Science at Louisiana
State University, has found a link between alterations in bird songs
and the rapid change in the surrounding habitat. The research will be
featured in the July 2009 issue of the American Naturalist.
| Elizabeth
Derryberry, a behavioral ecologist, has studied
this phenomenon
since her time as a graduate student at Duke University, where she
discovered tapes from ornithologist Luis Baptista. On these tapes,
which had been recorded in the 1970s, she quickly noticed that the
birds were singing quite a different tune than those happening right
outside her door. |
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“I was really surprised to find
that songs had changed in a similar way in so many different
populations,” said Derryberry.
Using
aerial photographs to map the vegetation and habitat changes that took
place between 1970 and 2005, when she began the research, Derryberry
was able to determine that in places where plant growth had increased,
bird songs were slowing down.
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“This is likely due to the
birds’ avoidance of sound
reverberation,” said Derryberry. “Because
California has steadily
increased vegetation in areas that had previously been cleared, the
birds slowed the frequency and tempo of their songs in order to avoid
reverberation distorting their mating song.” |
While California
has experienced a re-greening of sorts, many South American countries,
many of which are important habitats for rare and endangered species of
birds, are experiencing severe deforestation. Derryberry is now
studying the effects habitat on song in species in South America, where
widespread habitat destruction and global climate change may affect
song evolution...
Source: Source; Louisiana State University
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