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What do birds do in cold weather?

Whooper swans feeding in a snowy field at Toome, N. Ireland

Snow and frozen ground can make it hard for birds, such as these whooper swans, to find food

Image: Andy Hay

As you sit snugly by the fire this winter, spare a thought for our feathered friends. Their survival skills are tested to the limit when winter tightens its grip and food becomes hard to find.

We may grumble about the temperature, but the cold is actually not a big problem for birds. They are equipped with several layers of fluffy, insulating down to trap heat, so you won’t see your local robins and blackbirds shivering! 

In fact, conditions are positively balmy for those birds that have migrated here from the Arctic, such as brent geese and waders like knots and dunlins.

Food, glorious food

It is finding food and ensuring they eat enough of it to build - and maintain - adequate fat supplies to store on the body and ‘burn’ for energy that are the greatest tests for wild birds in winter. 

This becomes even more difficult in hard weather when snow and ice hide once easily available natural food. Water birds may be forced to leave iced-over lakes and rivers; the ground becomes too hard for birds like thrushes and lapwings to probe and natural food like berries, acorns and seeds is buried. 

'Finding a regular source of high-energy food such as a garden feeding station is the equivalent of winning the lottery for wild birds...'

The ability to fly is the survival 'trump card' for birds and can lead to sudden - and dramatic - changes in the birdlife of an area. A sudden reduction in numbers may be the only clue that your local birds have moved on temporarily, but if you keep your eyes peeled, the emigration of other birds can be very visible during, and after, cold snaps. 

Lapwings and golden plovers arranged in neat ‘v’ formation, and flocks of ‘chuckling’ fieldfares flying to the milder south and south-west in search of ice free pasture are classic signs of ‘hard weather movement’. Kingfishers and grey herons appear at the coast to fish in salty, ice-free water until their favoured streams and rivers thaw.

The flip side of birds leaving one area is that they suddenly appear in those that are less affected by the weather or where food is still readily available. Examples might be ducks such as pochards, goosanders and goldeneyes arriving at your local reservoir or an increase in the number of chaffinches and greenfinches coming to your garden feeders.

Hard winter weather may mean a change in behaviour rather than a change of location. Birds have to feed at an accelerated rate, but must also take adequate time out to rest and conserve energy. It is a fine balancing act and one they cannot afford to get wrong.

The smallest birds, like blue tits and goldcrests, have to effectively feed throughout the hours of daylight in winter and consume a vast quantity of food - as much as 30% of their body weight - to make sure they build the necessary fat reserves to get them through the long, cold nights.

Hoarders such as jays turn to the 'larders' they prepared in autumn when food was plentiful and dig deep in the snow to find the stores of acorn they stashed.

Birds of a feather...

Many birds become more sociable to improve their chances of survival during cold weather. 

Flocking together in winter improves the chances of locating food and huddling together during the critical night-time period helps conserve body heat. Treecreepers, long-tailed tits and wrens regularly do this. More than 50 wrens were once counted bedding down in a nestbox during cold weather - a snug fit indeed!

If you happen to be near a hospital, factory or shopping centre in the late afternoon, you might see large numbers of pied wagtails appearing to huddle together on the roof and take advantage of the warmth coming from each other - and the building!

Your garden can save lives

Male brambling on twig

Beautiful bramblings come into gardens when food becomes hard to find in the countryside

Image: Andy Bright

During cold snaps, you will almost certainly notice more birds coming into your garden to seek sanctuary from the harsher environment in the countryside – particularly if you provide food on a regular basis. The variety of species may increase too and you may be lucky enough to attract unusual visitors such as blackcaps and bramblings.

Finding a regular source of high-energy food such as a garden feeding station is the equivalent of winning the lottery for wild birds and a well-stocked garden is a real lifesaver.

Birds will become dependent on the food you supply, so it is important to make sure your feeders are kept topped up to prevent them from having a wasted visit. Providing a fresh, ice-free supply of water is another cold weather essential - drinking and bathing is a vital part of the daily routine of birds.

You may well witness a flurry of bird activity first thing in the morning – as they replenish energy lost overnight - and last thing in the afternoon - to prepare for the long night ahead.

How you can help

Male great spotted woodpecker at suet feeder

What food can you leave out for birds and how can you keep your feeding station hygienic and pest-free? Here you'll find the answers to all your bird feeding questions.

Feeding birds