As you may have guessed from the title of this post, we've been seenig otters on the reserve this week. One was spotted slinking into the water outside the Aird Meadow Hide on Friday afternoon and other visitors have reported seeing them in various places around the reserve. Gary (one of our volunteers) found spme spraints (for those that don't know, that's otter poo!) along the Dubbs Water trail, a surefire sign that they are going along that way quite regularly. Excellent!
However, we have also been spotting mink on the reserve, one of the few species that can be easily mistaken for an otter. Mink are non-native predators in the UK that have been proven to locally affect some breeding bird populations.
To tell the two species apart, i've often heard people say that, 'otters are cute looking, mink look mean' - well i guess that depends on you definition of 'mean' (and cute for that matter!). To clear up any confusion, here are some quick otter/mink comparisons that might help you work out which it is you are seeing:
European otter (Lutra lutra):
Appearance: Otters are always brown with a pale coloured stomach with long bodies, strong tails and webbed feet to help them swim quickly through the water. Their eyes are located at the top of their heads and they have sensitive whiskers growing around their snout which can help them detect prey. Otters benefit from a double-layer of fur: a thick waterproof outer coat and a warm inner one
Size: Males measure 115cm from nose to tail. Females are slightly smaller at 100cm
Weight: 7-9kg
Lifespan: Up to four years. There are rare instances recorded of otters living up to 12 years
Diet: Mainly fish and crabs but carnivorous otters also eat birds, small mammals and frogs
Family: Otters belong to the Mustelid family along with badgers, polecats, weasels, stoats and mink. Otters are the only amphibious family-member
Lakes, rivers and rocky or coastal areas are the otters' natural habitats, and they can also be spotted hunting their prey in quiet stretches of the canals. Otter territories are vast, covering up to 25 miles (40km) of watercourses and dense vegetation or wooded areas, which they use for resting purposes and for breeding holts. However, otters are timid and not often observed by humans. You are more likely to come across one of their smaller and more confident cousins, the mink.
European otter by Chris Gomersal (rspb-images.com)
American Mink (Neovison vison):
Appearance: Feral mink are naturally a chocolate-brown colour but farm-bred animals can vary in colour from white or grey through to black. Limbs are short and tails are approximately one third of their body length
Size: 42-65cm
Weight: 600g-1kg
Lifespan: Up to 8 years. Few survive beyond their second year in the wild
Diet: Mink are opportunistic predators who will happily eat a variety of fish, small mammals, birds and invertebrates
Family: Mustelidae
The Mink's long slim body is covered in glossy, thick dark brown fur with a white patch under the chin. They have short legs with partially webbed feet, which make them excellent swimmers. They can be found in wooded areas and fields near streams and lakes. They do not dig burrows, but instead take over dens abandoned by other animals.
Mink are semi aquatic predators able to hunt both aquatic and terrestrial prey. They can dive under water like an otter to capture fish, crayfish, and frogs. They can also capture terrestrial prey like birds, snakes, mice, voles, and rabbits. Mink are generalist predators focusing on whatever prey is most available and easily captured. These animals are mainly active at night and do not hibernate.
(Thanks to Wikipedia & British Waterways for this information)
So, next time you see a large water mammal, have an extra peek and see if it happens to be a mink, or if you are very lucky, an otter, and be sure to let us know either way!
Paula