A chaffinch perched on a snow-covered teasel in Kent

© Robert Canis/Minden Pictures

A chaffinch perched on a snow-covered teasel in Kent

This weekend, around 500,000 people in the UK are expected to take part in the RSPB Big Garden Birdwatch, considered to be the world's largest wildlife survey. To join in, all you need to do is spend an hour in your garden or local park and count the maximum number of each bird species you see at any one time. Last year, the chaffinch was the ninth most common garden bird, although numbers of this pretty finch have fallen by 57% since 1979. Make sure you keep your ears as well as your eyes open – you'll usually hear chaffinches before you see them.