More than half a million people are expected to be watching their garden birds at the weekend, for the RSPB’s Big Garden Birdwatch.

And with many of the UK’s most common garden birds and other creatures in steep decline, the charity needs participation more than ever.

The Royal Society for the Protection of Birds is urging people to count the birds visiting their gardens and capture their activity to help preserve and protect species under threat.

Launched 35 years ago, the Big Garden Birdwatch, which runs on Saturday and Sunday, is the biggest garden wildlife survey in the world with almost 600,000 people counting birds in their garden during last year’s event.

Findings from the 2013 Birdwatch indicated that starlings were at an all-time low and house sparrows, of considerable conservation concern, dropped by 17 per cent in gardens compared to 2012.

Big Garden Birdwatch provides the RSPB with masses of information about changes in numbers of garden birds in winter, and helps to alert conservationists to significant declines in UK garden species such as house sparrows and starlings.

Whatever happens with the weather this weekend, the results will be compared with those from winters in the past, stretching back to the first Big Garden Birdwatch in 1979. Any changes alert experts to track the winners and losers in the garden bird world, and long-term trends stand out even when year-to-year differences in the weather are taken into account.

And this year, for the first time in more than 30 years, participants are being asked to log some of the other wildlife they see in their gardens, too, such as deer, squirrels, badgers, hedgehogs, frogs and toads to help build a picture of how important our gardens are as habitation for these creatures.

Carol Barrett, a committee member with Airedale and Bradford local RSPB, says: “This is the world’s largest wildlife survey and it tells us what is happening on the garden patch, but also nationally as well, so it is really important to get that snapshot to see which birds are in decline.”

Carol says we can all do our bit by feeding birds and providing them with water and shelter, and not just during the winter months.

“We should be feeding the birds on a regular basis right through the year because they are so dependent on what we give them – not just food, but water as well. There has been a variation in weather as well and that affects the birds, too,” she says.

Carol suggests providing shelter along with nesting boxes and roosting places. Planting foliage to attract birds and bees into our gardens would provide them with natural nutrition.

Jo Keene, RSPB people engagement manager in Northern England, says: “Whether this is the first time you’re taking part in the Big Garden Birdwatch or you’re already an expert, there are plenty of ways to prepare and it’s a great opportunity to appreciate the wildlife where you live. Not forgetting it’s a brilliant feeling to be part of the world’s biggest wildlife survey – without having to leave the sofa!

“It’s not just the birds which need our help – almost half of our hedgehogs have disappeared in the last 25 years. So although we still want you to count our feathered friends during the hour, as they are a brilliant indicator of the health of our countryside, we also want to hear if you have ever seen other wildlife, such as badgers, squirrels or frogs in your garden or local park.”

As part of the Big Garden Birdwatch Airedale and Bradford local RSPB, along with the Friends of Northcliffe, are running a free bird watching session in Northcliffe Woods, Cottingley on Sunday from 2pm to 4pm.

Free guided walks and talks across the Bradford district will also be held.

For more information or to register to participate in the Big Garden Birdwatch, visit www.rspb.org.uk/birdwatch or call 0300 456 8330.