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A shortage of food in the wild has brought an influx of brightly coloured birds from the finch family into British gardens.

The number of finches spotted by householders in their gardens is at its highest level for five years.

The goldfinch – brown-feathered with striking yellow and blue patches and a red and white face – has a place in the top ten for the first time.

The success of the bird was expected because it is suited to the warmer temperatures in Britain and is also attracted to the current fashion for wilder, less manicured gardens. It has changed places with the greenfinch, which is now ranked at No 11.

One of the biggest climbers in this year’s Big Garden Birdwatch, which is run by the RSPB, is the siskin, which has distinctive yellow feathers and black stripes. It was spotted in three times as many gardens as last year. The species has increased in population by two thirds in four years and is now the twentieth most seen bird.

Scarcer finch family species, such as the brambling, which is identified by its burnt orange patches, and the redpoll, which has a ruddy red face and cheeks, have also been seen frequently. Experts are convinced that the main reason for these increased sightings is the lack of food in the wild. Many have been driven to fly west from Scandinavia, where conifer seed crops in particular were poor this year. The brambling and redpoll also arrived after a fall in the crop of beech seeds or “mast” in northern Europe.

The upsurge in garden finches may in part be explained by households leaving out niger seeds, which are sold as birdfood. Finches also have a clasped beak that allows them to feed on insects that nest inside thistles, which are common in wilder gardens.

André Farrar, of the RSPB, said: “It’s definitely been a good winter for finches. Many of them are here because of food supplies. Along with siskin increases, numbers of redpolls seen in gardens have skyrocketed.

“Both birds feed on conifers and deciduous seeds, so the figures suggest that tree seed supplies have been poor this year and they’ve been forced into gardens to find food.”

The survey, which is seen as an annual snapshot of how wild birds are faring in Britain, took place over the weekend of January 26-27.

Dr Farrar said that the warmer temperatures now meant that the audit was becoming a spring event rather than a winter one. Fewer birds have been seen in recent years – in part because of the absence of harsh weather.

Total bird numbers have dropped by a fifth this year compared with four years ago, with an average 28.4 birds seen per garden compared with 34.8 in 2004. There is concern about the low numbers of certain key species. House sparrows and starlings have retained their top slots but their decline has been dramatic, with sparrows down 64 per cent and starlings down 77 per cent since the first Garden Birdwatch in 1979.

Ornithologists are unable to explain the fall in numbers, although one theory is that new development and the concreting over of gardens to create patios and parking spaces has diminished the number of insects, which are essential for the birds to feed their young.

There was a note of cheer for song thrushes this year. Their numbers were up 80 per cent. The species moved up three places and is now ranked 21, although in 1979 it was the eighth most commonly seen garden bird.

Six million birds were counted in the survey by 400,000 people in 228,000 gardens or local parks.

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