Natural Inquiries - Redpolls
Flocks of redpolls cross Interior Alaska each winter
As flocks of redpolls cross Interior Alaska each winter, some invariably head up Pearl Creek Bowl, where they're funneled by the landscape toward Leonard Peyton's yard near Fairbanks. Most years, the small songbirds begin arriving in early December. Attracted by Peyton's feeders, more and more stop to fatten up on sunflower seeds, until by March hundreds swarm his yard and its adjacent forest.
Peyton has attracted songbirds to his feeders for more than 30 winters. The retired University of Alaska-Fairbanks biologist estimates he goes through 500 pounds of birdseed a year. But he doesn't just put out food: Since 1968 he has made a hobby of banding more than 20,000 redpolls. His resulting studies have significantly added to the body of knowledge about the birds. "There's no Alaskan more deeply involved with redpolls than Leonard," says Anchorage biologist Declan Troy.
Peyton's main interest is redpoll coloration. He asks and has found some answers to such questions as how feather patterns and colors change as the birds mature. He also has studied their movements. Like many other finches, redpolls sometimes go on long-distance "irruptions" in response to food shortages. Those travels can take the birds into Canada and northern regions of the contiguous 48 states.
Among the smallest of Alaska's birds at between 5 and 5.5 inches in length, redpolls are sparrowlike in appearance, with red splotches or caps on their heads and small black bibs. Males also sport pinkish breasts. They can endure the extreme cold of Alaskan winters partly because of a specially adapted seed-storage system: While feeding, they stockpile some seeds in an esophagal pouch, or crop, a feature shared with other finches. Through the nights, which in winter may last 20 hours or more, redpolls eat and gradually digest the seeds stored in their pouches.
The birds also have dense winter plumage they fluff for added insulation. Their core body temperature remains about 105 degrees, even when the air temperature drops as low as 58 degrees below zero Fahrenheit. So these tiny creatures can maintain a temperature 163 degrees warmer than the air. Says animal physiologist Pierre DeViche of Arizona State University, who has conducted arctic research, "Think if you could make a coat with that sort of insulative ability. It's incredible, really."
Peyton attaches a numbered leg ring to each bird he captures and records data including the colors of the bird's crown patch (which may range from cherry red to yellow-orange), cheeks, breast, undertail area and rump. He traps from January through May, and his goal, usually attained, is to band 1,000 or more redpolls every year. He has found that the males' breasts intensify in color with age, from light pink to a deep red. The color patterns of females change little. Rarely, however, mature females will develop pinkish red breasts.
Peyton has become convinced that the two redpoll species, common and hoary, are actually variations of a single species. Ornithologists generally describe hoary redpolls as pale birds, with white, unstreaked rump and undertail feathers; common redpolls are darker, with heavier streaking. "From what I've seen," Peyton says, "there's a complete gradation from almost white to dark brown redpolls and everything in between." He isn't alone: In 1985, after years of studying redpoll plumage and skeletal patterns, Declan Troy recommended in a professional paper that hoary and redpoll species be considered extreme forms of a single species. Still, the consensus remains that the two are separate species.
Few of Peyton's banded redpolls are ever recaptured, by him or others. He thinks the low recapture rate reflects the bird's short lifespan of about three years, as well as its erratic life-style and sometimes long-distance travels. The low return might frustrate most researchers, but Peyton isn't bothered. "Feeding and studying redpolls began as a sidelight," he muses. "But it just took over." And so he looks forward to another season of catching, banding and feeding the frenzied little birds that come to feed on his bait.
Like Peyton, Anchorage writer Bill Sherwonit looks forward to the return of redpolls to his feeders each winter.