Watch out for river mammals

One of the best places to watch wildlife on a summer's eve is on a riverbank. Here's a quick guide to the mammals you might spot.

Watch mammals along a riverbank article spread

Because summer nights are so short, mammals are often active well before dark. One of the best places to watch a diversity of species is on a well-vegetated riverbank.

Settle yourself down with a pair of binoculars an hour before dusk, with a tree or bank behind you to break up your silhouette, and wait.

Don’t make any sudden movements – when something appears, lift your binoculars slowly.

  • All species of deer can be seen along wooded riverbanks and in places with dense vegetation.
  • Chinese water deer prefer dense cover in the Fens and broads of eastern England, but are occasionally seen in reedbeds and riverside vegetation. In summer, their coats are redder. They can be recognised by their erect, hairy ears and button-like black eyes.
  • Neither sex has antlers, but the male has large, tusk-like canines.
Water shrews
  • The water shrew is the only species of shrew that dives for aquatic prey. It prefers fast-moving, unpolluted rivers and streams, but is also found in ponds, bogs and ditches.
  • Water shrews catch a range of invertebrates, tadpoles and even newts and small fish, which they bring ashore to eat. Their food remains can often be seen at favoured feeding sites.
  • Water shrews swim with a doggy-paddle and their coats look silver in the water. They are very buoyant, generally diving to less than two metres for just a few seconds.
Other predators
  • Common seals swim a long way up rivers. At the surface, the characteristic broad head can be seen, and they make side-to-side sweeps with their hind flippers.
  • Polecats occur in a wide range of habitats but are rarely seen swimming in the UK. They’re often spotted in wetland areas, especially where rabbits are common. 
  • American mink are similar in appearance to polecats but uniformly dark. Though active mostly at dusk and dawn, they can be spotted at any time and are sometimes seen bounding along riverbanks. They make shallow dives, usually for a few seconds, to catch fish and other prey. When swimming, they’re very buoyant, with half of the body above the surface.
  • Otters swim lower in the water with just their scalps and backs showing.

  • Many species of rodent can be seen along riverbanks.
  • Field voles are common in rough, grassy banks. Look for tunnels through the grass.
  • Harvest mice spend most of the summer in tall, grassy vegetation, especially reedbeds and the long grass beside rivers. They are secretive and rarely venture into the open, so watch for them creeping through vegetation, even over water.
  • Their summer nests are green and difficult to spot.
  • Young mice may be seen crawling on the nest surface.
  • Water voles and brown rats are often seen swimming in still and slow-flowing water.
  • Rats have pointed muzzles, larger ears and long tails.
  • Water voles have rounder bodies, shorter, chubby faces and smaller ears that just protrude from their fur.
  • Unlike rats, water voles are very buoyant. The first sign of a vole is often a noisy plop as it dives.
  • Many species of bat use wooded riverbanks as commuting routes, especially if there is a roost nearby.
  • Pipistrelles can be seen flying along tree lines near the water’s edge, hunting small flies and moths.
  • A single pipistrelle can eat thousands of midges in a night, which it catches in its wings and tail.
  • The bat most frequently spotted hunting low over water (usually less than 30cm above the surface) is the Daubenton’s.
  • This species prefers slow-moving or still water with few ripples, preferably with trees along the riverbank, where it ‘gaffs’ insects off the surface using its feet.
  • It also catches smaller insects in its mouth.


If you enjoyed this, why not read the previous part or the next part?   


We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here