The latest figures collected by bird survey volunteers have revealed the importance of the country's wetlands for wintering waterbirds.

Figures from the Wetland Bird Survey (WeBS), co-ordinated by the British Trust for Ornithology (BTO) in Thetford, revealed that during harsh winters these sites acted as a refuge for birds forced out of frozen continental Europe.

However populations of many species have declined in recent years, with some due to changing distributions in response to milder winter weather.

The report revealed that birds like the European White-fronted Goose, Mallard, Teal and Lapwing arrived to the UK in force from deeply frozen parts of Europe during 2010/11. This was in contrast to previous winters during which these and other species had declined in the UK, at least partly due to milder conditions.

However, despite the weather, numbers of others such as Pochard and Ringed Plover, fell further in 2010/11, to their lowest ever levels.

This is a strong indication that those species may be suffering from wider problems across Europe, the BTO said.

The UK's two largest inland wetlands, the Somerset Levels and the Ouse Washes, attracted especially large numbers of birds in the 2010/11 winter.

WeBS organiser at the BTO, Chas Holt, said: 'Over 3,000 WeBS volunteers braved the freezing winter of 2010/11 to count the UK's internationally important waterbird populations. We are indebted to their efforts.

'Against a recent history of population changes during milder winters, this fantastic effort is fundamental in helping to understand the response to periods of unexpectedly cold weather.

'The counts also contribute to the International Waterbird Census and thus help in the understanding of changes taking place across the wider world.'