Why do seagulls stand on one leg?

Valerie Osborne Snr Wildlife Adviser I have worked in Wildlife Enquiries for almost 20 years but am still amazed at the tremendous variety of queries that come our way. I am not an avid birdwatcher but do study those visiting my garden very closely. I am, however, a keen conservationist and try to do my bit to live a greener life. I love being able to share my knowledge with the people who come to us for advice and information.

Sent in by Sue Hurran, Northwood

Gulls regularly stand on one leg, appearing to have only the one. In some birds this may, occasionally be the case. Gulls frequently feed amongst netting and general rubbish so legs can get caught in fibres which, if they wrap around tightly, may eventually cause amputation.

However, on the whole they are very resilient and the reason for them adopting this rather unusual posture is probably just to rest one leg. During cold weather they tuck one foot deep within the feathers, keeping it snug and warm and change feet regularly to distribute the heat. In a popular identification guide to gulls, there are a couple of photographs of them standing on ice, both only using one leg.

Another bird which often rests one leg is the swan. These birds tuck a foot, at an almost impossible angle, high up on their backs. They look strange almost deformed and people become concerned that they are injured or the foot is trapped.