Dave Kilbey Photography

How do birds survive the winter?

Posted by Dave Kilbey on Monday 20 December 2010 at 2:02pm

How do birds cope with the cold and survive the long winter months?

  This article looks at some of the strategies they employ to ride out the worst of the winter weather.

In this cold weather spare a thought for our feathered friends.  Although well insulated against low temperatures birds can suffer high mortality rates in long periods of wintery weather.  The main problem is not the cold per se but a shortage of food.  If the ground freezes or we get a covering of snow, birds lose access to nearly all food sources and then have to rely on metabolising their finite fat reserves. Larger birds fare better in these harsh conditions but the smaller you are the greater the risk.  Goldcrests, wrens, tits and finches are among the first to burn through their reserves and succumb to the cold and their populations can quite literally be decimated by cold winters.

Wren by Dave Kilbey

Wren

Providing food for birds over the winter months makes a real difference to survival rates in local populations (goldcrests, wrens and treecreepers aside since they rarely visit feeding stations).  Fat balls, crushed peanuts, mixed seeds, mealworms and suet pellets are all excellent sources of energy for birds and if you feed and provide fresh water throughout the winter months you will develop a loyal following.

So how do birds survive at night?  When darkness falls they must rely on their fat reserves to see them through the night.  In addition they have various other strategies to cope with the cold.

  1. They will seek out sheltered, well protected nooks and crannies, dense foliage, gaps under tree bark, nest boxes and so on to roost in.  I have a blue tit that at dusk each evening uses a small hole in the mortar of my porch to gain access to what I hope is a very warm and cosy recess in my roof!
  2. Birds have a layer of down and are able to puff up their outer feathers trapping warm air against their bodies.
  3. They will also try to minimise heat loss from their extremities tucking one leg into their body feathers to save energy.
  4. They are able to greatly reduce the blood flow into their legs in cold weather to prevent heat loss.
  5. Some species will gather together for warmth at night.  Wrens, treecreepers and the-ever-sociable long-tailed tit are well known for this behaviour.
  6. Birds are also able to moderate their metabolism during the night, lowering body temperature slightly to reduce the amount of energy expended.

Robin in the snow by Dave Kilbey

Robin in the snow

Sadly though, if access to food disappears and freezing conditions persist, none of these strategies will be sufficient to prevent many unfortunate birds from perishing thus making feeding the birds not only a hugely enjoyable activity but a vitally important one.

Visit the main blog