Redpolls are small songbirds that reside year-round in Denali. Studies suggest that common redpolls can tolerate colder temperatures than any other small songbird. Redpolls depend on several unique adaptations to survive in northern environments. Their plumage weight in winter is twice that of summer and they often erect their feathers in winter to retain heat. Redpolls eat large amounts of high-calorie foods before nightfall, store the foods in a pouch in their esophagus, and digest the foods after they have gone to roost. Like other resident songbirds, redpolls seek out sheltered places for roosting.
During winter, redpolls occur in large flocks. Their numbers fluctuate greatly among years, most likely due to changes in food supplies. Our best source of information on redpoll abundance during winter in Denali comes from the annual Audubon Christmas Bird Count conducted by local volunteers on the eastern end of Denali. The numbers of redpolls counted on the Christmas Bird Count in Denali has ranged from one to 360 individuals. Greater variation has been recorded further north on the Fairbanks Christmas Bird Count where annual numbers of redpolls have ranged from 36 to 2,238 individuals.
A unique life history characteristic of redpolls is their apparent lack of territoriality. They are one of the few songbirds that are not territorial during the breeding season. In winter, large flocks search northern forests for food. These flocks are principally nomadic and may move thousands of kilometers in search of food.
Denali scientists are learning more about the abundance and distribution of breeding redpolls by conducting systematic surveys during the summer.