Is global warming putting garden birds at risk by making them lay their eggs earlier?

This change could eventually threaten the survival of many garden species such as robins, chaffinches, swallows, blue tits and great tits.

They are laying earlier, with some nests filling up with eggs almost ten days sooner than in the 1960s.

Hungry mouths: Blue tits are having their young earlier

It is thought the phenomenon is being driven by climate change, with the caterpillars needed to feed their chicks disappearing earlier in the year.

So far, our garden birds have kept pace with the changes to the caterpillars' lifecycles, but in time they could be left behind.

'The caterpillar lifecycle has the potential to shift even further and they could get out of synch which would be very bad news,' said Dr David Leech, of the British Trust for Ornithology.

Climate change is also taking its toll on many species of ducks, geese and wading birds which migrate to the UK each winter from their northern and eastern nesting grounds.

The decline of the dunlin is of particular concern, an annual report on Britain's birds warns.

Once the most common wading bird in winter, numbers have fallen by more than a fifth in the last 25 years, leaving them at their lowest since records began in 1980.

The State of the UK's Birds report showed how species were being forced to adapt their behaviourin order to survive, altering nesting and migration patterns and going further afield for food.

It is thought many wetland birds are 'short stopping'  -  taking advantage of the milder winters on mainland Europe rather than flying on to Britain.

For instance, a dramatic reduction in duck numbers over-wintering on Britain's largest lake, Lough Neagh in Northern Ireland, suggests the creatures are taking advantage of continental waters that would usually be ice-bound.

The report, compiled by conservation groups including the RSPB, the British Trust for Ornithology and the Wildfowl & Wetlands Trust, also said many farmland and woodland birds were continuing to decline, falling foul of intensive farming, pollution and habitat loss.

But it is not all bad news, with tree sparrows among the species enjoying a resurgence.

Last year was a bumper one for song thrushes, with the wettest summer on record ensuring the birds had a plentiful supply of earthworms for their young.

Dr Mark Avery, conservation director for the RSPB, said: 'This year's report shows that climate change is with us already and from our gardens to our seas, birds are having to respond rapidly simply to survive.

'As often before, birds are acting like the canaries in a mine shaft and giving us early warning of dangerous change.'