[EBB Sightings] New info on Anna's

From: SCIENCE NEWS. Week of Aug. 25, 2007; Vol. 172,
No. 8 
Tail singers Susan Milius
 The sound effects of Anna's hummingbirds, widespread
along the West Coast, have been misunderstood,
according to a new test. A male Anna's hummingbird can
make sounds with its tail. Some of the males' most
dramatic noises aren't vocalizations, as has been
thought. Instead, the birds make noises by whipping
their tails through the air. Males, with iridescent,
rose-colored throats and heads, perform aerial dives
when courting a female or confronting another male.
For a display, a male flies high in the air and then
drops nearly straight down. When he's plummeted to the
level of his intended audience, he pulls out of the
dive while sounding an explosive squeak. In the late
1970s, ornithologists decided that those notes came
from the birds' vocal organs. Chris Clark and Teresa
Feo of the University of California, Berkeley have
challenged that idea by removing some birds' outer
tail feathers. A clipped male still dives, but he no
longer makes the sound as he bottoms out. Clark also
tested the tail feathers in a wind tunnel and was able
to make noises like the birds'. The researchers
reported their findings at the July 21?25 meeting of
the Animal Behavior Society in Burlington, Vt.
Ornithologists have documented a wide variety of
noises made by bird wings, from cricketlike rubbing
sounds to aerial whistles. A tail-feather sound
effect, though, is quite rare, says Clark.