For the Birds Radio Program: Fall Bluebirds

Original Air Date: Sept. 10, 2008 Rerun Dates: Sept. 24, 2019; Sept. 26, 2012; Sept. 22, 2011; Aug. 14, 2009

Why is there a gap between seeing the last bluebirds in our nest boxes and flocks appearing in fruit trees?

Duration: 4′07″


Sometime in March or April every year, I get calls and emails from people exulting in their first bluebird of spring. Those who set out bluebird houses search for the birds’ return anxiously, and when these lovely birds return, they call attention to themselves with song.

Then, in September and October every year, I get calls and emails from people seeing bluebirds again, often in large flocks. But now the people are puzzled. If they maintain bluebird houses, they often haven’t seen the birds in many weeks, since the last babies fledged. Didn’t they leave a long time ago? What are they doing?

Bluebirds don’t return to their nest boxes after the babies fledge. After they’re independent and their parents are busy with a new brood, the young from first broods move off their parents’ territory and associate with other young bluebirds. These flocks are fairly inconspicuous—the birds are often driven away by nesting adults if they’re noticed on their territories, so they try to escape detection.

But as fall arrives, adults lose their territorial aggressiveness, and these flocks of juveniles, and small flocks of adults with their last babies, start moving about more conspicuously again. Like robins, they switch their diet from primarily insects to primarily fruits, and can be rather eye-catching in berry trees. I once had a flock of 18 alight on a rooftop at Treehaven, a University of Wisconsin field station in Tomahawk. They rested a few minutes and then took off again—it took a while for me to catch my breath. Sometimes in fall bluebird will sing briefly, and we can often hear their mellow call notes, but unless we’re paying attention, we’re not going to notice them. Many small groups pass over Hawk Ridge each fall, but unless people are listening for and watching the dickey birds going by, they miss them.

Bluebirds winter in the central and southern states and in northern Mexico. In years when food is abundant, they wend their way south in a leisurely way, and so can be reported as late as November, though the largest movements through the upper Midwest seem to be in September and October. The better the variety of fruiting berry bushes and trees available, the more likely you are to get them in your yard. Blueberries, black cherries, elderberries, currents, dogwood, hackberry, pokeberry, redcedar, and sumac are all good choices if you’re planting for them. Always try to get locally native varieties. Unlike the first bluebird of spring, you never know that you’ve seen the last bluebird of fall until weeks later. But whether a particular bluebird is the final one or the second-to-last, or you’re fated to see bazillions of them in fall, each provides us with a red-letter day. Bluebirds lead short lives fraught with danger, and are far more aggressive to one another than people once realized, but they produce lovely sounds and go through their lives with an integrity few humans can match. A bluebird may be feeling rather cranky when we exult in spotting “the bluebird of happiness,” or it may, indeed, be happy–we humans don’t understand avian emotions at all. But we do understand our own feelings, at least enough to know that when we see a bluebird, whatever the month, we can’t help but feel happy.