Birds and cold weather

• Additional warmth for songbirds comes from skin muscles that fluff up feathers to trap heat near the skin. People’s “goosebumps” are skin muscles trying to fluff up long-gone body hair.

• Arteries and veins intertwine at the base of a songbird’s legs to allow heat from arterial blood to warm up cooler blood in the veins and conserve heat in their feet.

• Songbirds tuck their head and beak inside shoulder feathers for warmth.

• They also find warmth in the cover of thick bushes, tree hollows, rocks and building ledges.

• They’ll snuggle with their mates to keep warm, as Carolina wrens do on door wreaths.

• Songbird plumage is drab in winter because dull colors absorb warmth from sunlight, just as bright summer plumage reflects sunlight to keep them cool.