Our garden birds have feathers that are incredibly good at coping with the challenging British weather. They don’t actually grow a different set of feathers for winter and summer, but change the condition, arrangement and use of their plumage.
When it’s raining
Feathers play a front line role in helping to keep the bird waterproofed, as they are naturally water-resistant. Birds also spread preen oil over their feathers, taking it from a small bland near the base of the tail.
When the rain lands on the bird, rather than soaking it through, the water cleverly runs off the outer feathers.
Feathers overlap to create a protective outer layer, while fluffy down feathers underneath trap warm air.
When it is cold and rainy, birds can fluff themselves up to increase the insulating air layer.
When it’s cold
Birds use their feathers to keep toasty and warm by fluffing them up to trap warm air close to their bodies. You might have noticed birds doing this in the garden. It’s funny how it can make a small bird look much bigger.
Bills or beaks and feet can be neatly tucked into plumage to help reduce heat loss.
It is interesting to note, that it isn’t the feathers themselves that are generating the heat. They are merely acting like an insulated winter jacket.
When it’s hot
During warmer temperatures, birds do the complete opposite, holding their feathers more loosely and close to the body so that heat can escape.
Some birds will sit with their wings held aloft from their bodies to increase the exposed surface area and let air circulate.
Birds also use their feathers for shade, particularly around the head and body.
When it’s windy
Feathers are not rigid, they’re highly flexible and can be positioned by the bird to allow wind to pass over them.
In windy weather birds will also seek shelter in places such as hedges, shrubs and trees.
Keeping feathers in tip-top condition
After the breeding season, many UK garden birds will replace worn feathers with new plumage for the autumn and winter. This is known as the annual moult. Feathers gradually deteriorate from exposure to sunlight, rain, abrasion and everyday wear so replacing them is vitally important.