Yo! Whose Yodel is That?
Like your own voice, the yodel call of a male loon is
one of a kind. Research by Dr. Charles Walcott of Cornell University
has verified that
each loon male's yodel is a distinctive "voice print" that
stays the same while the loon is on breeding territory. But there's more.
Preliminary data indicate that a male's yodel might change substantially
if that loon is chased off its territory by another male loon and forced
to move elsewhere. How common is that? Researchers will try to record
yodels from as many displaced males as possible in hopes of finding the
answer.
Hear Three Yodels
Dr. Walter Piper, a researcher on the project, sent us some recordings of yodeling
loons.Try your ear at distinguishing the yodels of three different males from
three different lakes. It takes several minutes to download each file, but
once they're downloaded you can play them repeatedly to listen for the differences.
See Three Yodels
When scientists analyze sounds, they can use more than their ears. Sometimes
they also study a picture of the sound, called a sonogram. This picture
is actually a graph, showing the frequencies of the sounds on the Y-axis
and time on the X-axis. Using sonagrams is very tricky, and some people never
quite master it. You be the scientist! Listen to the loon recordings
and follow their sonagrams. Can you HEAR the differences in the calls? Can
you SEE the differences? Give yourself some practice; it's not easy!
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Call #1 |
Call #2 |
Call #3 |
Dr. Piper can distinguish each of these three male loons by their calls. But
what if loons really do make different yodels when forced to change territories?
If this really happens, learning how to recognize males with vocal tagging
is not likely to be very useful in the long run. Dr. Piper will keep us informed.
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