Birds may look fragile, but they have evolved to conserve energy in smart ways. During winter, many species reduce activity to preserve precious calories. You may notice that birds appear calmer and move more slowly on particularly cold days. Some birds, such as tits and robins, also fluff up their feathers to trap warm air close to their bodies, acting like a built-in duvet.

Night-time is the most dangerous period for birds, when temperatures can drop well below freezing and predators lurk in the shadows. To cope, birds seek sheltered roosting spots such as dense hedges, evergreen trees, nest boxes, or even gaps in buildings. Many species gather in groups during the night to share warmth - wrens, for example, have been found huddling together in groups of 20 or more.

As winter approaches, birds instinctively eat more to build up fat reserves. This extra layer of fat acts as insulation and also provides energy during long nights when they cannot forage. Small birds only carry enough fat to last them a single night, which means they must feed again as soon as daylight returns.

When insects and berries become scarce, birds switch to whatever food sources remain. Blackbirds may shift from insects to fallen fruit, while blue tits become regular visitors at feeders offering nuts or seeds. Birds are adaptable and opportunistic, but winter puts that adaptability to the test.