Britain's warming climate is helping rare birds to breed here in record numbers, research showed yesterday.

The Rare Breeding Birds Panel reported that little egrets, firecrests, cranes and Mediterranean gulls all chalked up their highest numbers since monitoring began in 1973.

The most up-to-date figures, from the panel's 2006 survey, showed that little egrets increased their numbers to a recorded 434 breeding pairs, with the actual population estimated at around 600 pairs.

Avocets are just one of the breeds finding it easier to breed in a warmer climate

There were 341 pairs of firecrests, thought to be the result of the founding of plantations, which provide them with suitable habitats, and milder winters.

The study, published in this month's edition of the journal British Birds, also showed increases in wood larks, Cetti's warblers and Dartford warblers - again thought to be linked to milder winters.

However, warmer weather could be having a negative impact on some northerly species, including the purple sandpiper and Temminck's stint, which each recorded just one bird in 2006.

Also, some species which might be expected to benefit have actually seen numbers decline, including the golden oriole, marsh warbler and the wryneck - of which no pairs were recorded in 2006.

Mark Eaton of the RSPB said: 'The report is further proof that our bird populations are changing. Avocets, Mediterranean gulls, firecrests and Cetti's warblers all enjoyed their best year on record, but a century ago these species weren't even breeding in Britain.

'However, the report shows that the wryneck, which was formerly one of our more widespread birds, is slipping closer to extinction.'

Some birds which attempt to breed only very rarely in Britain tried to do so in 2006, including black-winged stilts and bee-eaters.

According to Mark Holling, the secretary of the Rare Breeding Birds Panel, the firecrest is 'a species which has found new habitat and a climate to suit', although the most recent cold winter may have knocked the small bird back.

Egrets have found it easier to breed and remain in the north during the less harsh winters

According to Mr Holling, these species are typical Mediterranean birds which make occasional breeding attempts in Britain and their presence is not yet part of a general spread, as in the case of little egrets.

But attempts by bee-eaters to breed have become more frequent and may be an indication of a spread in the future.

Some species of birds which might be expected to benefit from warming temperatures have actually seen numbers decline, including the golden oriole, marsh warbler and the wryneck - which had no records at all in 2006.

Mr Holling said the decline of golden orioles may be linked to changes in the availability of habitat, for example the felling of poplar plantations they favour.

'It might be getting warmer, but if their habitats have been degraded, they can't find the spaces to successfully breed,' he said.

But a number of species, particularly wetland birds, have responded well to the provision of habitats such as nature reserves, while birds of prey have generally benefited from protection.

'Species such as avocet, bearded tit and marsh harrier have all responded well to the safe provision of breeding habitat and have expanded into other areas because there is a nucleus of good habitat.'

It's not good news for everyone - warblers have seen their numbers decline

Cranes, a bird driven to extinction when the Fens were drained, managed a record 10 pairs - including one pair away from the long-established Norfolk Broads population - and was helped to some extent by nature reserves and other suitable habitat.

In some cases, though, birds will just 'turn up anywhere and make a nesting attempt' including a black kite which nested with a red kite and fledged two young in the Highlands.

It's also been a good year for Mediterranean gulls