Tuesday, March 12, 2013

Anna's Hummingbird territorial display

Anna's Hummingbird display
Anna's Hummingbird singing, Cooper Mountain Nature Park, Beaverton, Oregon. February 15, 2013 by Greg Gillson

Anna's Hummingbirds rival Great Horned Owls for earliest nesting bird in the Pacific Northwest. Unlike other hummingbirds, this resident year-round species is the only one regular in the United States in winter (a resident race of Allen's Hummingbird lives on the Santa Barbara islands group off southern California) Many Anna's Hummingbirds lay eggs in February in the Pacific NW. The males don't help with nesting duties or raising of the young. They are just "trophy husbands," providing a pretty face and some DNA for the next generation.

By mid winter the males are claiming territory for their "singing." These are the only North American hummingbirds that sing. The song is an insect-like buzzy noise: "beez-zee-zee-zeeb-zee," etc. from a high perch. It's kind of like some of the starling's buzzy, squeaky song notes, but reduced in size to a large insect.

I was so happy to find a male singing recently in some winter sun. The angle was just right for the black throat feathers to refract sunlight back in a metallic rosy hue and provide some great photos in a natural (non hummingbird feeder) setting.

Another male hummingbird flew into the blackberry tangle. It didn't quite have the full breeding gorget. So, perhaps it was a younger bird. It stayed quietly inside the protection of the tangle. The singing male became more agitated and flew and behaved in a stylized way.

The territorial bird rose quickly straight up 70 feet or more--nearly out of view, like it was on an elevator, levitating, keeping it's body level to the ground. Then it dove at high speed toward the ground and angled toward the interloper in a J-shaped flight. It made a popping squeak or chirp at the lowest point of its flight quite near the invading hummingbird. Then it continued up about 20 feet and hovered in place for about 3 seconds, completing the J-shaped flight path. Then it rose again and repeated the same display flight several times. I was able to get the photo below as it hovered briefly at the end of its J-flight.

Hovering Anna's Hummingbird
Hovering hummingbird in display flight.

The popping chirp noise in the display flight is probably made by the tail feathers. If I hadn't seen the bird and associated sound, I would not have known what it was. The sound was similar to the bark of a chipmunk or squirrel or even some kind of insect sound (if it was summer instead of winter).

At any rate, a sunny winter day, a great series of photos, and interesting behavior I had never observed before. Birding at it's best!

Singing Anna's Hummingbird
Victorious hummingbird has vanquished the interloper.