LONDON - The Royal Society for the Protection of Birds says Britain's cuckoo bird, known for its distinctive call, is in danger of extinction.
A new report from the society says 51 other species also face the same threat.
Society spokesman Tim Webb says the report found that 21 per cent of Britain's bird species face extinction unless steps are taken to protect them.
He says the cuckoo and other migratory birds that visit Britain in the summer have suffered population loss largely due to a decrease in food and water supply in sub-Saharan Africa.
''The Sahara desert is spreading and the birds are having a hard time flying out in good condition ... There isn't just one single problem, there are a host.''
The society said the cuckoo population in Britain has declined 37 per cent since 1994.
Native birds such as the herring gull also made the threatened list.
Six species did see a recovery in the past seven years, however. The report said the woodlark has seen a ''dramatic'' increase in population, as had the stone-curlew.
Webb said these birds saw healthy gains thanks to an increased effort to maintain woodlands that would allow their numbers to grow.