Not a murmur heard from London's starling flocks

London's starling population is on the verge of collapse, the RSPB warned today.

The organisation has urged people in the capital to keep an eye out for the once common huge clouds of the birds, known as a "murmuration".

The phenomenon forms when up to 100,000 of the birds choose where to spend the night. They were once so common in London that the sheer weight of them perched on the arm of Big Ben stopped the clock.

A spokesman for RSPB London said: "We are asking for sightings of large clouds of starlings within the M25. Witnesses can post details on our Facebook site."