It is being called the kingfisher factor, and is a striking indication of how things have changed on Britain's canal network. On waterways which a generation ago were clogged with grime and pollution, a massive clean-up has taken place. And, with wildlife flourishing as never before, Britain's most strikingly beautiful bird – the kingfisher – is making a comeback.
But they are not only becoming increasingly common on rural canals. With their spectacular cobalt-blue and chestnut plumage, kingfishers can be seen on the Regent's Canal at Islington in north London, and in cities such as Leeds and Manchester. The birds are often spotted, for example, near the British Waterways offices at Fearns Wharf on the Aire and Calder Navigation – just two minutes' walk from Leeds city centre. This summer, despite the wet weather, 300 kingfisher sightings were recorded by the public during British Waterways' fourth National Waterway Wildlife Survey. The study, which had a special focus on the bird, indicated healthy populations in many places on the 2,200-mile canal network.
It is a far cry from as recently as 20 years ago, when many canals, especially urban ones, were in effective foul-smelling dumping grounds covered in scum. The poet Philip Larkin, witnessing the typical sights of England from a train, wrote in The Whitsun Weddings in 1964 of "canals with floatings of industrial froth". But money has been poured into regeneration and the water-borne motorways of the Industrial Revolution have been revived as valued amenities.
The presence of a canal nearby can add 25 per cent to the value of a house, for example, and their importance for wildlife is increasingly being recognised, especially as "corridors" that different species can move along. The presence of wildlife, in turn, proves that a canal is healthy.
"We are delighted to hear of so many sightings of kingfishers on our waterways," said Mark Robinson, the national ecology manager at British Waterways. "As well as being a strikingly beautiful bird, kingfishers are an important indicator of the general health of the waterway ecosystem. Like the big cats on the African plains, kingfishers are at the top of the waterway food chain. They need fish to feed on, and fish need small invertebrates, and so on.
"Good populations of kingfishers, even in urban areas, show the important role that waterways have in greening our towns and cities by providing wildlife corridors which help to sustain populations of a variety of both common and endangered species including bats, water voles and otters."
As a direct result of the poll findings, several schemes to improve kingfisher habitats are planned, including the installation of boxes, posts and tunnels at the Regent's Canal, the Staffordshire and Worcestershire Canal and the Grand Union Canal at Leighton Buzzard in Bedfordshire.
More than 4,000 bird sightings were recorded during the survey. The kingfisher was the fourth most-common species spotted, behind the mallard, mute swan and grey heron. There were also plenty of sightings of some of Britain's rarer species, including water voles, otters and bats. Other, more unexpected animals which were reported were seals and an alligator snapping turtle – the largest freshwater turtle in North America.
The survey shows that the warm autumn which followed the wet summer has caused confusion in the animal kingdom. Common darter dragonflies, which have normally disappeared by this time of year, are still about, while two unusual southern insects – the saw fly and a grizzled skipper butterfly – have been seen in the Midlands for the first time.
There has, however, been no repeat of the alleged sighting of a crocodile in the Stroudwater canal in Gloucestershire two years ago. "We investigated this, and it was probably a large pike," Mr Robinson said. "At least we think it was. We haven't had any records since, and as far as we know, we haven't lost any dog-walkers."
The species discovered
Mallard (431 sightings)
Mute swan (382)
Grey heron (366)
Damsel fly (148)
Grass snake (89)
Water vole (71)