Animal

Hungry herons and the great otter comeback: the wildlife of canals


Canals are often seen as a kind of second-class version of a river. Perhaps that goes back to their industrial history, but from a wildlife point of view canals and rivers are more or less interchangeable.

Visit a city canal on a fine, sunny day in spring or summer, and you’ll see plenty of dragonflies and damselflies on the wing. Some, such as the red-eyed damselfly, banded demoiselle and scarce chaser, have a special preference for the slow-flowing water of a canal, sometimes perching on waterlilies in the sunshine.

Wait patiently and a kingfisher may appear, usually heralded by its persistent, high-pitched call, followed by a dazzling flash of blue and orange as it flies rapidly up or down stream.

A kingfisher



If you’re patient, you might see a kingfisher. Photograph: Gareth Whiston/Alamy

Herons often hunt for fish or frogs, either perched on the bank or, standing stock-still, in the shallow water by the edge. In recent years, they have been joined on many canals – especially in southern Britain – by the Persil-white little egret, which first colonised Britain in the 1990s, and can now be seen along canals in London and other cities.

Several species of waterbird build a floating nest, tethered to aquatic vegetation, a short distance from the canal bank to ensure they are safe from land predators such as foxes. These include the coot, moorhen and great crested grebe which, when temporarily absent from the nest, covers up its eggs with water weed, staining them from their original white to a dirty green. Once the grebe’s humbug-striped chicks have safely hatched, they often hitch a ride on their parents’ backs.

A great-crested grebe carries two young on its back along Blackwall Basin in London



A great crested grebe carries two young on its back along Blackwall Basin in London. Photograph: Victoria Jones/PA

Like most mammals, otters and water voles are much harder to see than any of these birds.

Otters almost disappeared from English waterways during the 1960s and 1970s, due to a combination of pollution and persecution. But since then they have made a major comeback, and are now found in canals in a number of cities, including Birmingham. However, being mainly nocturnal they are not seen very often, though their spraints (droppings) are evidence of their presence.

An otter



Otters are back in business on England’s waterways. Photograph: Ann and Steve Toon/Alamy

Your best chance is to see otters and water voles is to visit very early in the morning, before the cyclists, joggers and dogwalkers appear along the towpath, and simply sit and wait. Evenings, too, can be a good time to look out for the shier canal wildlife.

Stephen Moss is an author and naturalist who teaches an MA in travel and nature writing at Bath Spa University.

The canal revolution series looks at what our changing waterways reveal about modern British cities. Follow Guardian Cities on Twitter, Facebook and Instagram and use the hashtag #canalrevolution to join the discussion or sign up for our weekly newsletter





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