The harsh winter may have significantly reduced numbers of kingfishers on Britain's rivers and canals, British Waterways said yesterday as it launched its annual wildlife survey.

The organisation, which looks after 2,200 miles of the nation's waterways, is calling on the public to head down to their local canal, river, reservoir or dock to spot birds, animals and insects.

This year British Waterways is focusing its survey on kingfishers, amid fears the frozen waters and icy temperatures experienced for weeks on end this winter could have hit the bird hard.

Mark Robinson, British Waterways' national ecology manager, said although nature was "pretty resilient" to events such as the hard winter, many species would have suffered.

"The good news is that our waterways act as green corridors connecting towns, cities and farmland and providing vital shelter and a winter larder for wildlife struggling to survive."

But he said some species would have been particularly hard hit.

According to British Waterways, the harsh winter of 1962/1963 killed off between 80 per cent and 90 per cent of kingfishers.

"Frozen water and plummeting temperatures may have significantly reduced kingfisher populations, with the possibility that many lost the battle against the cold.

"It is therefore particularly important for us to monitor what species will need our support over the coming year and we're asking the public to help us do that," Dr Robinson said.

He added: "Now that the weather has warmed up, kingfishers are starting to nest and so now is a great time to see them."

British Waterways is raising money to improve habitat for birds found on the waterways, including providing nesting tunnels for kingfishers and preserving their perches.

The measures also include providing reedbed habitat alongside canals and in reservoirs for rare bitterns and reed buntings and putting up nest boxes for grey wagtails nesting near lock gates and for barn owls.

Last year the wildlife survey recorded more than 42,500 sightings including almost 300 different species of birds, amphibians, reptiles, insects and mammals.