For
once this is an encouraging environmental tale of recovery and success.
A species that was once nearly extinct in
the county is now returning to much of its former distribution countywide.
This
is one of the most elusive and difficult mammals to see in the wild! If
lucky, you may find footprints or spraints, especially where streams join
rivers or under bridges and around weirs (all places where fish might
congregate).
Otters
had all but disappeared from the county by the 1980's. Dieldrin
type pesticides were introduced in the 1950's; these poisons ran
off into rivers and accumulated in fish. Further harm to otters was caused
by human disturbance, loss of habitat as rivers were "tidied"
up and an increasing number of road deaths as traffic increased. Only
a tiny remnant population hung on in the
south of the county.
However, by the early 1990's there had been some movement into
the southern Solway coast of Cumbria from strong populations on
the Scottish side of the Solway. By the mid 90's colonisation
of the west coast of Cumbria had occurred and populations in the
south were recovering. Surveys in recent years have found evidence
of otters throughout the Eden valley and its tributary rivers,
on the Solway Plain and on the northern stretch of the west coast
of the county and on all the short rivers in the south of Cumbria
(see map). It just remains for a further spread into the south
west (Rivers Calder, Irt, Esk, Mite and Duddon) before we can
truly say that the species has recovered in all its former habitats.
By
2008 numbers had recovered to the point where otters have become
a nuisance at many fisheries in the county. I recently watched
one for twenty minutes as it caught and devoured a 18-20 inch
carp from Ulverston Canal, which had been kindly stocked for it
by the local anglers' association!
On
the Solway coast otters are partly marine, hunting on rocky shores with
kelp beds and occasionally out to sea. Males may travel up to 30 km, but
females rarely more than 6 or 7 km. Mostly road kills, therefore, tend
to be of male otters.
The
otter has five toes, unlike cats and dogs
with four. The toes are strongly webbed, but this may not show in a footprint
except in soft mud. Indeed the smallest toe may not show, but the print
can be distinguished because it is not symmetrical. The rear paw print
would be about 11 cm from tip of middle toe to the base (see image on
the left of a left paw); the front paw is quite a bit smaller at about
8 cm. The mink has a similar footprint, but it is smaller in size.
Otters
leave their droppings or spraints in prominent
spots. Recent research suggests that spraints are less likely to be left
if other otters are present in low numbers or when supplies of food are
higher (mid-summer). The spraint is typically 6 to 8 cm long and 1 cm
in diameter and comprises mostly fish bones and scales. Dark when fresh,
it ages to grey - looking like cigar ash or 'coke' (an old name for an
otter spraint).
Mink
are smaller (smaller than a cat, whereas an otter is larger than any cat),
have a pointed muzzle compared to the otter's broad muzzle and has a short
bushier tail compared to the otter's longer tail that is very thick at
the body and tapers to the end.
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