The Royal Society for the Protection of Birds’ Big Garden Birdwatch — the world’s largest wildlife survey — takes place this weekend.

Last year, a record-breaking 551,881 participants helped celebrate the Big Garden Birdwatch’s 30th birthday, spotting more than 8.5 million birds across almost 280,000 gardens.

Sarah Kelly, Big Garden Birdwatch co-ordinator, said: “Big Garden Birdwatch provides a fun activity for all the family in the depths of winter. Participation just keeps increasing, I believe in part, because it’s so easy to join in. By giving up just one hour of your day, you can make a real difference to our knowledge of garden birds. We’re able to distinguish the ones that are doing well from those that need our help.

“Once an activity for children, Big Garden Birdwatch is now popular with children and adults alike and we’re particularly keen to get more families involved this year. Why not make a day of it by creating bird feeders made from recycled household goods or bird cakes for the birds in your garden?”

Ms Kelly added: “Big Garden Birdwatch is a vital way for you to contribute to a significant piece of wildlife research without leaving the comfort of your home — in fact, we’d really rather you stayed indoors, so as not to disturb the visitors to your garden. You don’t need to be an expert but we really couldn’t do it without your help.”

Past Big Garden Birdwatch findings have enabled the RSPB to embark upon studies to identify the cause of certain species’ decline as well as steps we can take to help them recover.

The house sparrow has, despite topping the chart, shown a rapid decline since 1979, dropping from an average of ten per garden to only 3.6.

Results have shown the tit family as having tremendous staying power with blue, great, coal and long-tailed tits all having staked their claim in the Big Garden Birdwatch top 15 with regular appearances, year on year. In 2009, the long-tailed tit made it into the top ten for the first time in 30 years.

Contributors to the Birdwatch are asked to spend one hour over the weekend January 30/31 counting the birds in their garden or local park and to record the highest number of every bird species seen at any one time.

For further information and online resources, visit the RSPB website, www.rspb.org.uk/birdwatch.

An online results form will be available until February 19, 2010.