Wildlife survey finds rare species in capital

Hundreds of miles of London's canals and rivers are awash with a rich array of wildlife, brimming with rare and protected species.

Skylarks, kingfishers, mink and even the Chinese mitten crab have all been sighted beside river banks and towpaths, from Woolwich in the south-east to Uxbridge in the west.

Even more surprising and rare were sightings of a seal in Docklands, an oyster catcher at Battersea and a great crested grebe on the Thames at Guildford.

The sightings have been logged by British Waterways from a survey of visitors as part of a nationwide project recording the biodiversity of inland waterways.

More than 10,000 people logged on to its website to help chart the species inhabiting London's waterway network.

Sightings of mallards and moorhens were commonplace but there were also reports of the more retiring residents of the riverbank, such as the otter and water vole.

But Mary Norden, British Waterways' London ecologist, said the number of sightings of terrapins was not such a good sign.

"The non-native reptiles are usually pets, bought during the Ninja Turtle cartoon craze, which have been released into the waterways when they become too large for their owners to keep," she said.

"They can live for up to 30 years and, although there is no evidence they are breeding in the wild , t hey are quite destructive - eating birds' eggs and small animals like baby

ducks. Canals, rivers and lakes are havens for all sorts of wildlife from birds, fish and mammals to insects, reptiles and amphibians.

"The waterways bring a unique cross-section of the countryside into the heart of London and right on to our doorsteps."

Ecologist Jonathan Brickland said that mink were also causing a problem for native species.

"The predatory American mink has thrived on Britain's waterways since their release from a number of mink farms," Mr Brickland said. "They are linked to the widespread loss of water voles.

"But the return of otters to some areas seems to be linked to mink reduction, and so the situation may improve as otters return to our waterways."

The furry-clawed Chinese mitten crab was sighted in the Grand Union Canal, Southall. The creatures originally came from the Far East. They spend most of their life in fresh water but must return to the sea to breed. A skylark was seen at Thamesmead - a rare sight as their numbers have halved since 1990 and by 75 per cent since the Seventies, owing to changing farming practices.