"Some of Britain's most cherished spring visitors are disappearing in their thousands. Ornithologists say species such as the cuckoo, nightingale and turtle dove are undergoing catastrophic drops in numbers, although experts are puzzled about the exact reasons for these declines.

The warning, from the [Royal Society for the Protection of Birds], comes as the songs of the cuckoo, nightingale and wood warbler herald the return of spring. In the case of the cuckoo – "the simple bird that thinks two notes a song", according to the poet William Henry Davies – its call has become synonymous with the arrival of warm weather. It is the quintessential bird of spring.

Yet there is now a real risk that, with other migrant birds from Africa, it may no longer make its annual appearance in our woodlands, said Dr Danaë Sheehan, a senior RSPB conservation scientist. The call of the cuckoo could be silenced in the near future unless scientists can unravel the causes of the drastic decline in their population, she said."

Robin McKie reports for the Observer April 24, 2011. [2]