Sometime before Halloween, some birds in my neighborhood do a curious thing. They start to sing.
Birds sing mostly in spring and early summer to attract mates and defend territories for breeding. By late summer, most birdsong has tapered off.
But sometime in mid to late October, certain bird species like red-winged blackbirds and American robins start singing again. Often they are snippets, but the other day while walking past a creek, I heard the blackbird give its telltale springtime call, “onkalee,” amid a chatter of other blackbirds. A robin interjected its “cheerily, cheerio.”
Recently, a white-throated sparrow in my yard also sang a soft, off-key version of its breeding song, “oh sweet Canada, Canada.” (Someone came up with that mnemonic because these sparrows nest in Canada.)
This is not the full-fledged chorus of song that greets us in late winter and spring, and it’s often interjected with chips, calls and other noises that don’t sound very melodious.
But to me, birdsong in fall is a whisper of things that have been, and things that are to come. For example, birdsong in fall could be a juvenile practicing its melody for next year’s breeding season.
In fact, Jeffrey v. Wells, Ph.D., author of the “Birder’s Conservation Handbook,” thinks that could be the case with some birds species.
“One of the species that we often hear singing short and often odd, off-key renditions of songs in the fall is the white-throated sparrow,” he wrote in a recent article. “Many of these are young birds, just hatched a few months before. … They are refining their songs so that they will be ready to join the ranks of breeding adults next May and June to compete for a territory and a mate.”
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Certain bird species also physically react to the changes in day-length year-round. In spring and early summer, the levels of testosterone in a bird increase as daylight hours increase, and that encourages singing. For a period in fall, the amount of daylight hours mirrors what we’ve experienced in spring, about 12 hours of light and 12 hours of dark. Does that autumn window stimulate the birds to produce more testosterone and sing?
Scientists think that’s what happens with the white-crowned sparrow, a bird that migrates through northern Illinois in spring and fall.
The white-throated sparrow I heard singing in fall is closely related to the white-crowned sparrow. The white-throated also is a migrant in Illinois, showing up mostly in fall and spring. In fall, white-throated sparrows spend time in my yard for several days kicking back leaves and looking for hidden insects. They utter a plaintive whistle-like call, but every once in a while, one utters a tentative song.
Another native sparrow that sings in fall is the song sparrow. This species breeds in Illinois and few may even spend winter here.
Song sparrows also respond to day lengths in autumn that mimic that of spring and early summer. But they don’t have high levels of testosterone in their bloodstreams in fall like the white-crowned sparrows do. Scientists think another hormone called DHEA increases in song sparrows in fall, and that could be what encourages this species to sing. Scientists think the same may be true for American robins.
As for the red-winged blackbirds, author and bird specialist Laura Erickson has heard them sing in fall as well, way up in Minnesota where she lives. She said on “For the Birds,” a radio program, that, “As with just about all birds, the sex organs of red-winged blackbirds shrink when the breeding season is over … but it happens in some birds faster, and in some birds more slowly, than average. The birds singing in marshes in autumn are apparently still feeling a bit hormonal.”
Eventually the white-throated sparrows and red-winged blackbirds leave the neighborhood for winter, and true wild birdsong is mostly absent. But my ears are perked and ready for that first song of the northern cardinal in February. “What cheer, cheer, cheer,” the cardinal will bellow, and we’ll begin to hear more birdsong again.
Sheryl DeVore has worked as a full-time and freelance reporter, editor and photographer for the baiduhai and its subsidiaries. She’s the author of several books on nature and the environment. Send story ideas and thoughts to [email protected]