Subject: [Tweeters] Anna's Courtship Flight Dives
Date: Jan 18 12:54:28 2013
From: Doug Schurman - doug at bodyresults.com


On Wednesday I witnessed a male Anna's Hummingbird making courtship flight
dives in my front yard.



I was just getting out of the car and I heard this whistle like chirp sound.
I had heard it once earlier in the day at Juanita Bay but couldn't figure
out what species was making it. I looked around the yard and finally saw
there was a female Anna's sitting high up in a tree and a male Anna's in the
air. The male would fly straight up above the female like a helicopter and
get maybe 50 to 100 feet above her and then would dive straight down at the
female. Right before it got to the female it change direction to fly
horizontal. Exactly at the change in direction is when you could hear the
sound. There were about 8 dives in a row I was aware of.



My understanding is that originally people thought the sound was vocal but
later it was figured out that sound came from the air going through their
tail feathers.



Here's more from Cornell's website



The dive display of the Anna's Hummingbird lasts about 12 seconds, and the
male may fly to a height of 40 m (131 feet) during the display. He starts by
hovering two to four meters (6-13 feet) in front of the display object
(hummingbird or person), and then climbs in a wavering fashion straight up.
He plummets in a near-vertical dive from the top of the climb and ends with
an explosive squeak within half a meter of the display object. He then makes
a circular arc back to the point where he began. On sunny days the dives are
oriented so that the sun is reflected from the iridescent throat and crown
directly at the object of the dive.



It was very cool behavior to witness.



Happy birding

Doug Schurman

NE Seattle