Biology Reference
In-Depth Information
CHAPTER 6
Singin' in the Rain: Bird Vocalizations
On a frigid winter morning as I walk through the woods, when even the wind is silent,
the sound that penetrates my warmest fur-lined hat is the rich song of a cardinal, or
another song lovely in its simplicity — the
Hey, sweetie!
of a chickadee. By spring,
birdsong erupts well before dawn, and the morning chorus has so many voices that it
may be hard to pick out that same cardinal and chickadee, but they're in there. The
beautiful voices that fill the spring air make the whole world seem alive and happy.
How do birds produce such complex sounds? Why do they sing? And how do we
learn to identify their voices? Those are the questions people send me.
Making Beautiful Music
Q I went on a bird walk and my leader pointed out a Wood Thrush song. It was cos-
mically beautiful! How can a single bird produce such an amazing sound?
A
Because birds produce their sounds with their syrinx, or song box, which has two
branches and two sets of muscles, they can produce harmony with their own voice. Birds
in the thrush family have very complex muscles in their syrinx, allowing them to produce
breathtakingly complex tones independently in each branch.
That morphological description may begin to explain how the individual tones are pro-
duced, but what can explain the sheer beauty of these sounds? Do male Wood Thrushes
take as much pleasure in singing as we do in listening to them? Do female Wood Thrushes
select mates for a dry, analytical reason such as how many different tones in what arrange-
ment each male sings, or because the beauty of a song takes her breath away? Science
gives us a lot of answers, but it might take the Vulcan Mind Meld to resolve that one.
Q I live in the woods in northern Minnesota, and in May and June I usually wake up
to a Winter Wren singing near my cabin. How does such a tiny bird produce so many
sounds so quickly?
A
As with other splendid bird songs, our experience of Winter Wrens transcends a mech-
anical understanding of sound production. In 1884, the Reverend J. H. Langille described
his experience listening to the Winter Wren, “I stand entranced and amazed, my very soul
vibrating to this gushing melody, which seems at once expressive of the wildest joy and
the tenderest sadness.”
