The song of the male Anna's hummingbird is hardly a thing of beauty, at least to human ears. It is a thin, high-pitched, grating noise, usually three syllables in length.
I'm certain it inspires fear in the hearts of other males that would jump at the chance to pilfer nectar from the flowers or sugar water from the feeder in another's territory. I'm also sure the song is attractive to females, but the message is lost on me. I get no sense of fear or love from the squeaky song. Because the males in our area do not migrate, their songs can be heard any time of year.
Most females have the good sense to leave for the fall and early winter, but a few remain, toughing out harassment from the territorial males. Male hummingbirds, in general, are rather mean and don't know how to treat a lady most of the year. A quick sip of sugar water at a feeder is simply not tolerated. Even when courting, I'm not sure the male always gets it right. He seems torn between aggression and romance. Females put up with a fair amount of abuse before the male sorts it out.
Females arrive in numbers beginning in January and February. Breeding starts early, when spring flowers are the main source of food.
When the male finally does get things figured out, the courtship flight can be fun to watch. He flies up high above a perched female and sings. Then he dives at high speed straight toward the perched female. At the bottom of his dive, just a few inches above the head of the female, he makes a loud, sharp "pop." The male quickly returns high above the female to sing and repeat the routine.
It is the pop that has interested ornithologists. Is it a call like a peep or chirp, or is the sound made in some other way? Until recently we haven't been sure. High speed photography of courting hummingbirds has finally provided an answer. At the very bottom of its dive, the male fans its tail wide, just for an instant. When the outer tail feathers are presented to the rushing air, they vibrate. At that instant, the tail feathers produce the pop.
Perhaps it is the speed of the dive or the shape of the tail that determines the loudness of the pop. This likely provides the female with information about the strength and vigor of the male and may determine whether she chooses to mate with him.
Non-vocal sounds are common among other hummingbirds. You can always tell when a male rufous hummingbird is in the garden. While in flight, the outer primaries of its wings produce a distinctive metallic whine. The flight of the female is nearly silent.
The high meadows of the Rocky Mountains are even noisier with the sound of male broad-tailed hummingbirds rocketing about. Their wings are even louder than those of rufous hummingbirds.
Grab those earplugs ... or not. Spring is coming, and it's going to get noisy.
Stewart Janes is a biology professor at Southern Oregon University. He can be reached at email@example.com.