Chilly weather poses its own challenges for birds. if you spend your life beating gravity you need to be light, so birds can't afford to put on a little timber around the middle. here are some tricks they've evolved to survive the season's cold, wet and wind.
Leg to stand on
Birds have all sorts of sticking-out bits like legs, facial skin and beaks that don't have warming feathers. Watch birds resting in your garden, ducks on the local pond or waders roosting on estuary mud. They all do that trick of drawing one leg up into the coziness of their under-belly down. It makes good sense, halving the amount of leg exposed to the elements. I've even watched the long-legged birds like godwits and avocets fly short distances, take off and land on that single leg.
Big yourself up
Many birds appear to swell in size on particularly cold or windy days. They’re ﬂufﬁng up their feathers, with muscles at the base of each shaft causing them to stand more upright and trapping more air. If they’re still feeling the chill, birds can shiver just like us to create extra metabolic heat. It’s a last-ditch strategy, though, as it uses up precious fat reserves.
Sun bathing isn’t a pastime you’d associate with winter. However any of the sun’s energy – even if it’s weak and wintry – can give birds a degree or two of free heat; even a degree up the scale is one degree a small bird doesn’t have to ﬁnd from its own heat budget. So look out for birds huddled in those sheltered sun traps. Out in the wild, anywhere that gets ﬁrst sunlight is a good place to concentrate your bird watching efforts.
When roosting or resting in a safe location birds tuck their head under their wing. By placing their bill and therefore their nares (ornithological speak for nostril) into those aforementioned warm air pockets, they don't inhale cold air and therefore don't have to waste valuable energy heating it up.