Fall bird chorus is in full swing

Text Size: A | A | A

Print this Article Email this Article

Late August and early September are wonderful for many reasons, but bird song is not one of them. It's the quietest time of the year. Only the occasional mourning dove drones on, and even then it sounds more like a job requirement than real enthusiasm. Bewick's wrens still utter a few songs from the bramble patches along the Bear Creek Greenway warning off other males, and the irrepressible house finch still offers a couple of songs. But that is about it.

It is a different story in late September and October, however.

If you are attentive, you can hear the echo of spring. Golden-crowned sparrows newly arrived from the willow thickets in grizzly country in the Alaskan outback try out songs at dawn and dusk. Robins sing faint songs before heading off to roost. Lesser goldfinches sing muted songs, and starlings serenade us with clicks, whistles, gurgles and a few songs borrowed from other birds.

There are several reasons for fall singing. For one, the day length is similar to that of early spring. Day length triggers many physiological changes in birds. Hormone levels surge a bit and some singing results.

The second reason for fall singing relates to the way in which songbirds learn to sing. While some birds, such as flycatchers, will sing the "correct" song even if reared in complete isolation, true songbirds like robins, warblers and sparrows must learn their song.

The initial learning process begins as nestlings and continues for a couple of weeks after they leave the nest. It's as if a young bird has a template in its brain that it applies to each song it hears. A young white-crowned sparrow may hear a robin sing. Nothing happens. A song sparrow may sing. Nothing happens. A white-crowned sparrow sings, and all sorts of neurons light up in the brain like a casino in Las Vegas.

Studies that have looked at this are amazing. Somehow the young bird recognizes the correct song and locks on to it. This brief exposure to the correct song at a critical period enables the young male to sing a proper song and join the ranks of breeding males next spring. Laboratory studies have shown that a young bird that never hears the correct song during this critical period is a misfit and never learns to sing properly.

The story, however, is not quite finished. Practice makes perfect. While many of the quiet songs we hear in the fall are those of young birds practicing and perfecting their songs, there may be one final period of refinement the following spring as young males vocally spar with their neighbors — but time is short. Females arrive just a few days after the males establish territories, and the young males better be ready. The females expect a polished performance.

So as the leaves turn colors and the nights chill, put on a sweater, step outside and savor the quiet fall chorus. It may not be perfect, but it is the best show around until next March and April.

Stewart Janes is a biology professor at Southern Oregon University. He can be reached at janes@sou.edu.

Reader Reaction We welcome your feedback on this story, or any follow-up story ideas you might have. Please send a letter to the editor to letters@mailtribune.com, or submit story ideas online here. When submitting a letter to the editor, please review our submissions policy.

Print this Article Email this Article