The goldfinch was among the top 10 most commonly spotted birds
Sightings of finches in UK gardens hit their highest level for five years this winter, an annual RSPB survey shows.
It said milder winters meant the goldfinch in particular was spending winters here in larger numbers.
However, the overall number of birds counted in the survey - held in January - has dropped by 20% since 2004.
Milder winters mean food is not as scarce and birds do not have to search in gardens, while some species are in long-term decline, the RSPB says.
The national Big Garden Birdwatch survey took place on 26 and 27 January this year and is aimed at providing a snapshot of the UK's bird population.
Sparrows and starlings
Nearly 400,000 people counted more than six million birds in gardens or parks.
An average of 28.4 birds were counted per garden in this year's study, compared with an average of 34.8 per garden in 2004 - a trend partly attributed by the RSPB to declines in key species.
It said numbers of some of the most common bird species, such as the house sparrow and starling, had dropped dramatically over the 29 years the survey has been running.
For the foreseeable future we're in a period when we've got much milder winters
The 2008 survey showed sightings of the yellow and black siskin have increased by almost two-thirds over the last four years and it was sighted in three times as many gardens as last year.
The bird, a member of the finch family, has become one of the study's top 20 most commonly spotted birds for the first time, with large numbers driven from Scandinavia where conifer seed crops have been poor in recent months.
Furthermore, the goldfinch - encouraged by warmer temperatures in the UK - made it into the top 10 for the first time.
TOP TEN GARDEN BIRDS
1: House sparrow
4: Blue tit
7: Collared dove
9: Great tit
Source: RSPB Big Garden Birdwatch
Andre Farrar, of the RSPB, said it had "definitely been a good winter for finches".
He said: "Many of them are here because of food supplies.
"Along with siskin increases, numbers of redpolls seen in gardens have skyrocketed."
He said warmer temperatures mean the national survey is now almost a "spring" event rather than a winter one.
Dr Farrar said the lower number of sightings in recent years were in part due to the absence of the kind of harsh weather once seen during the Birdwatch weekend.
He added: "These are very profound changes to our climate we are seeing.
"For the foreseeable future we're in a period when we've got much milder winters."
Sparrow numbers have dropped 64% since the first Garden Birdwatch in 1979 and starling numbers have fallen by 77% in that time, while the blackbird and chaffinch have seen numbers fall by 39% and 28% respectively.
In stark contrast, the woodpigeon and collared dove have seen numbers rise by 665% and 411%.