The house sparrow was the most spotted garden bird in 2005

More than 30,000 children took part in the 10-day Big School's Birdwatch 2005 survey, counting 57,000 birds.

The starling was the most common school bird, while the house sparrow topped the Big Garden Birdwatch 2005 survey.

The RSPB's Big Garden Birdwatch, when householders spend an hour recording birds, takes place this weekend.

The nation-wide survey gives the RSPB a snapshot of bird numbers and species in the UK each year and is an indicator of changes in the environment.

In 2005, the appearance for the first time of the ring-necked parakeet in the top 20 birds spotted in London is thought to be an indicator of warmer winters.

TOP 20 BIRDS 1 House sparrow 2 Starling 3 Blue tit 4 Blackbird 5 Greenfinch 6 Chaffinch 7 Collared dove 8 Wood pigeon 9 Great tit 10 Robin 11 Dunnock 12 Magpie 13 Long-tailed tit 14 Goldfinch 15 Coal tit 16 Jackdaw 17 Carrion crows 18 Wren 19 Rook 20 Feral pigeon 2005 RSPB Big Garden Watch

The RSPB estimates numbers of the south Asian bird - believed to have escaped from captivity - could reach 50,000 by 2010.

Ros Patching, the RSPB's education officer, urged people to get involved in the survey.

She said schools' could provide excellent habitats for a range of different birds.

Starlings, for example, like to stay together in groups. They enjoy foraging for food on hard surfaces, such as playgrounds, but also probing in lawns and damp grass for worms and grubs.

They also sit on buildings and in trees to whistle, chatter and shout their various calls.

"Playgrounds can be noisy places, but they are only noisy at certain times of the day," she said.

"Quite often there are quiet spots in schools, and hedges and fields, and quite a good variety of habitat, and they can be really good places for quite a wide variety of birds."

The schools survey runs until 3 February. The Big Garden Birdwatch 2006 takes place 28-29 January.