The common redpoll (Carduelis flammea) is a small brown and gray finch with a rosy chest and red cap that is abundant year round in open subarctic areas and northern forests. These tiny birds are known to survive extremely cold temperatures and have adapted to harsh winter conditions in a number of ways. During long Arctic nights, they often sleep in snow tunnels to preserve body heat. They are also equipped with an esophageal diverticulum, a throat pouch, for temporarily storing seeds until they can eat them in a warmer more protected spot. They regurgitate, shell and swallow the seeds when they are in a place that is safe from predators and protected from the elements. They will also fluff their contour feathers to create an insulating layer of air to help them stay warm.
Redpolls often hang upside down from small branches where they are feeding.