Snow Caves Keep Ptargimans Cozy on Cold Winter Nights
When temperatures plummet, some northern birds create burrows to take advantage of snow's natural insulation.
Transcript:
This is BirdNote.
It’s small consolation to those of us shoveling the stuff, but snow is a great insulator. Light, fluffy snow can be up to 90 percent trapped air, just the thing to keep bears and ground squirrels and other hibernating mammals warm — and birds, too.
Ptarmigan, those small arctic grouse that molt into a white plumage each autumn, spend the long winter nights in cozy caves they excavate in snow. At dusk, they dig an entrance, then bulldoze their way beneath the surface to hollow out a well-insulated sleeping chamber. In truly harsh weather, they will hunker down in their caves through the short arctic day, too.
Common Redpolls move south to escape the arctic winter. But even then, their wintering grounds in southern Canada and the northern US can be snowy. These tiny, goldfinch-like birds with the bright red cap break through the snow with their heads, then burrow horizontally for up to a foot and a half. Come morning, when the sunshine warms the air, they pop up out of the roosting cave, leaving the smooth blanket of snow pocked with redpoll-sized craters.
Something to look for next time you’re out in your down parka with a thermos of hot chocolate.
For BirdNote, I’m Mary McCann.
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Credits:
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Willow Ptarmigan [50031] by Leonard J. Peyton. Common Redpoll [196451] by Bob McGuire.
BirdNote's theme music was composed and played by Nancy Rumbel and John Kessler.
Written by Rick Wright
Producer: John Kessler
Executive Producer: Dominic Black
© 2016 Tune In to Nature.org January 2016/2018/2020 Narrator: Mary McCann
ID# burrowing-01-2016-01-13 burrowing-01