Biology Reference
In-Depth Information
Bird songs can carry us away with their beauty.But the more we learn about them, the
more thrilling those songs become.
Male mockingbirds may have two distinct repertoires of songs: one used in spring and
another used in fall.
BIRDS THAT MAKE SOUNDS WITH FEATHERS
As a Mourning Dove flies past,
you may hear a whistle — a sound produced by its
feathers. The function is unknown, but some scientists speculate that sound may signal
alarm when the birds take off. Male Mourning Doves also use their wings to produce
noise when attracting the attention of females. They launch from a perch high into the
air, flapping their wings loudly, then glide down as part of a courtship display.
Many other birds also produce sounds with their feathers. Ruffed Grouse make an ex-
plosive thunder as they burst into flight. Common Goldeneye wings make a whistling
soundinflight that cancarrymorethanamile. American Woodcockwingfeathers make
a distinctive twittering sound as the birds fly.
In a territorial display, male Anna's Hummingbirds plummet through the air nearly
vertically from heights of 66 to 131 feet (20-40 m). At the bottom of their dive, they
make a loud squeaking noise, similar to a sound they make while singing from a perch.
Using ultra high-speed cameras, researchers found that the birds actually produce the
dive squeak when they spread their tail at the end of their fall, causing air to vibrate the
feathers rapidly.Thescientists wereabletoproducethesamesoundbyblowingastream
of air over a hummer's outer tail feather.
Similarly, Wilson's Snipes use their stiff outer tail feathers to produce sounds when
they display in spring. The snipe circles high overhead and then drops, speeding up to
as much as 52 miles per hour in the dive, while spreading its tail. The vibrations of the
two stiff tail feathers produce a peculiar hum as the wing beats send the air over the tail
in pulses. The distinctive sound,
woo-woo-woo-woo-woo
, called
winnowing
, is audible
from up to half a mile away.
Tropical manakins make an array of bizarrely wonderful sounds with their wings,
from rapid firecracker-like snaps to tonal hums with their feathers. High-speed video
showsthatwhenaClub-wingedManakinflipsitswingsoveritsback,itknockstwospe-
cialized wing feathers together, creating a high-pitched tone as one feather slides against
the other, like a bow on the string of a violin.
