Bird Atlas survey 2007-11 is launched today by the British Trust for Ornithology. It is Britain’s biggest bird survey.

50,000 birdwatchers participate in the Bird Atlas survey, which will take place over the next four years.

The Bird Atlas survey counts the numbers of more than 250 species of British birds, taking into account how climate and habitat change will affect bird populations.

The Bird Atlas will then help determine conservation work for the next 20 years.

Bird Atlas: the essential facts

The UK is divided into 4km sq areas of research

Individuals can choose one or more areas to study in timed visits over different seasons

Others will undertake counts at random times

For queries, email birdatlas@bto.org

The last Bird Atlas was drawn up 20 years ago; this survey of Britain, led by the British Trust for Ornithology, will be finished in 2011.

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