Kingfishers, newts, toads and ladybirds survived last winter's cold snap despite fears the freeze could reduce sightings of important wildlife in 2010, British Waterways says today.

Reports by nature-lovers this year suggest the gradual return of otters might not be the only heartening tale of the canal and riverbank. There was also an encouraging increase in sightings of house sparrows, whose decline in towns and cities has been a concern in recent years.

More than 40,000 wildlife sightings were recorded between March and September with ubiquitous mallards (6,799), Canada geese (3,354), moorhens (1,758) and swans (1,702) topping the list. But there were also 1,641 sparrow sightings, up 23% on the previous year.

However the biggest rises were in newt sightings (251, up 446%), toads (228, up 256%), ladybirds (585, up 238%) and kingfishers (596, up 217%). Otter spots rose by 194%, but still totalled only 50.

Mark Robinson, British Waterways' national ecology manager, said: "I'm delighted that we've had so many records of kingfishers from across the country this year. The results really show the resilience of nature and the importance of our canal and river network in providing vital shelter and food for a wide variety of wildlife."

Increasing reports of some species were "testament to the huge improvements in water quality and habitat management that we, along with local communities and partner organisations, have worked hard for", said Robinson. "They are all great indicators of a healthy and thriving ecosystem."

Recorded sightings of mink – and introduced species – dropped by 36% on 2009, down from 75 to 48. This might be related to the recent increase in otters as they out-competed mink for territory, said Robinson. "This may also be great news for the UK's fastest declining mammal, water voles, which often make a tasty meal for the predatory and aggressive mink. In fact, we have seen another slight increase in the number of water voles sighted compared to 2009."