Another new bird for the backyard bird list — Common Redpolls visited the thistle feeder yesterday along with their cousins the Pine Siskin.
Redpolls (Carduelis flammea) are easily recognized (and distinguished from House Finches) by the square patch of bright red feathers on the top of their head. The males sport some rosy red feathers on neck and breast as well.
Usually these birds travel around in a huge flocks (hundreds of individuals), which might be mixed species of redpolls and siskins, moving from area to area in response to local seed resources. It looks like the Redpoll in the photo above might be even smaller than the Pine Siskin sitting on its left (slight hint of yellow in the wing feathers and streaked breast feathers IDs this species). But they are really hearty birds, wintering all over northern North America where temperatures routinely into double digit negative numbers overnight.
Stocking up each day on fat-rich seeds like thistle, these tiny birds can rev up their metabolic furnace and maintain their normal 105F/41C body temperature all night at temperatures as low as -40C (which is also -40F). Amazing!