Friday, June 12, 2009
Elizabeth Derryberry, post-doctoral
researcher at the LSU Museum of Natural Science, has found a link between
alterations in bird songs and the rapid change in the surrounding habitat. Her
research will be featured in the July 2009 issue of the American Naturalist.
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.
"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.
"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.
###
Louisiana State University
Just like a caged birds that sings like mad.
We never understand them.
Perhaps the birds are cursing like mad not sing as we have misunderstood.
I already dun understand dog language.. let alone bird language.
But difference between us n the animals,is that we appreciate music.
人讲人�,鸟讲鸟�
lang kong lang ue, ciau kong ciau ue