Terrestrial Mammals
of Shetland
It is no
surprise that an isolated island group like Shetland has a very restricted
terrestrial mammal list - approximately a quarter of the number of species
found on Mainland Britain have been recorded in Shetland. All of these
have been introduced by humans at some time in the past - indeed the only
native Shetland mammals are the Grey and Common Seal. The following are
accounts of all known species of terrestrial mammals to have occurred in
Shetland. The records are as complete as possible but details of any
omissions or additions would be welcomed.
Hedgehog
Erinaceus europaeus
A
relatively recent Introduction to Shetland recorded by both Harvie-Brown
(1892 & 1893) and Evans & Buckley (1899) who indicate that the species was
introduced in about 1860, or slightly earlier by the farmer at Veensgarth,
Tingwall (central Mainland). Any subsequent introductions are unrecorded
as the species apparently spread rapidly from the initial introduction and
is now widespread on Mainland and most of the inhabited islands except Out
Skerries.
Photo: Hedgehog -
photographer unknown
Rabbit
Oryctolagus cuniculus
The date of
introduction into Shetland of this species is not known although the first
mention of the species in the literature reports that Rabbit warrens were
present on the West Isle, Burra (at the holes of Minn and at the Links of
Meal), and on the isles of Oxna, Hildasay and Papa Little in 1654 (Leigh
1908). Thereafter it was reported as widely established on links and holms
in Shetland by about 1680 and Evans and Buckley say that the species was
introduced on Foula in about 1879. Today the Rabbit is widespread and
numerous on Mainland and most inhabited islands as well as the majority of
uninhabited islands.
Brown Hare
Lepus capensis
The species
was introduced to Shetland at Cunningsburgh (south Mainland) in about 1830
by the MP Samuel Laing. By the 1890's they had spread (thinly) over much
of the south and east side of Mainland and a few were reported to have
reached the west Mainland. Small numbers were also released at Reafirth
and Windhouse on Yell in 1882 by J. Harrison but these apparently quickly
disappeared from the island. The species appears to have survived
reasonably well on Mainland during the early 1900's but they apparently
caused 'considerable damage to the crops' and were widely and
enthusiastically persecuted. Several were apparently still present in the
Lunna area in 1935 although the last record of the species alive in
Shetland is of two trapped in a turnip rig at Spiggie in 1937. There have
been no records since that time.
Mountain Hare
Lepus timidus
Mountain or 'Blue' Hares were introduced into Shetland by Mr. Anderton
from Perthshire who introduced two pairs to Vaila (an island off the west
Mainland) in about 1900. In addition, Dr. Munro brought individuals from
Scotland to the Kergord estate in about 1907. The species is now
widespread throughout Mainland and is apparently still surviving on Vaila.
Photo: Mountain Hare -
photographer unknown
Field or Hill Mouse
Apodemus sylvaticus
Thought to
have been introduced from Norway by Norse settlers although Venables &
Venables (1955) considered this species to be a likely indigenous species
to Shetland, indeed the only likely indigenous land mammal, and a possible
subspecies of A.sylvaticus. It is ubiquitous throughout Shetland
although is apparently absent from Out Skerries. Separate races have been
described - for Yell and possibly Mainland (A.s.granti - Hinton
1914), Foula (A.s.thuleo - Hinton 1919) and Fair isle (A.s.fridariensis
- Kinnear 1906). Venables & Venables summarize the characters of these
subspecies as follows:
-
A.f.friariensis - Fair Isle Field Mouse. Blue-white belly,
usually no chest spot. Average size; head and body 109.5mm, tail
103.2mm, hind foot 24.1mm, ear 16.1mm.
-
A.f.grantii - Yell & possibly all Shetland Field Mouse. Shorter
tail, slight skull differences, yellow-brown chest spot between
forelimbs. Average size: head & body 101.5mm, tail 91.8mm, hind foot
24.0mm, ear 16.2mm.
-
A.f.thuleo - Foula Field Mouse. Hind foot very large but sole
pads as small as fridariensis. Normally no chest spot. Average size:
head & body 96.15mm, tail 93.6mm, hind foot 24.9mm, ear 15.5mm.
(Measurements of size given above refer to adults only).
House Mouse
Mus musculus
Presumably
introduced into Shetland by Norse settlers this species is ubiquitous
throughout Mainland and the inhabited islands.
Black or Ship Rat
Rattus rattus
Introduced
from ships with the earliest recorded occurrence either immediately prior
to, or sometime between 1654 and 1680. The only documented localities were
at Lerwick Harbour and and on Whalsay. The Whalsay colony was apparently
discovered in 1904 and was known to have been still in existence in
1951.The species is almost certainly now extinct in Shetland and there
have been no certain occurrences since at least 1990 although it has been
known to be on some visiting vessels, e.g. klondykers.
Brown Rat
Rattus norvegicus
This
species was originally Introduced to Shetland from visiting vessels but
its place of origin and date of introduction are unknown although Venables
& Venables suggest that it may have been in about 1730. It has been
reported on all the large inhabited islands except Yell (where it has been
extinct within living memory) and Fetlar, although it appears to also be
absent from most of the west Mainland.
Fox
Vulpes vulpes
Apparently
a single individual was introduced in Shetland the 1860s (locality
unknown) but it was shot. From about 1990 onwards there have been rumours
of sightings of a fox in the Sullom, Voe and Delting areas. On the 31st
August 1996 a dog fox was found dead on the road at Olna between Voe and
Brae, apparently shot at close range. However rumours of others have
persisted in the same area. It appears a few animals have been brought in
to Shetland and let loose deliberately or possibly even transported here
as carcasses, possibly for some time. An 'Arctic type' individual was also
found dead at Voe on the 14th February 1997. The animal was a fully-grown,
adult male and was in very good condition, seemingly well-fed and with
long claws, suggesting that it had not been fending for itself in the
wild. There are no records of breeding.
Photos: the 1996
Fox found at Olna and the 1997 'arctic type' individual found at Voe -
Kevin Osborn
Stoat
Mustela erminea
Probably
introduced in the late 1600s in the Dunrossness area (Venables & Venables).
seventeenth century. Currently they are widespread throughout Mainland but
apparently absent from the main isles (Yell, Unst, Fetlar, Whalsay),
although they were introduced on Whalsay around 1900 to 'destroy rats and
rabbits' but they subsequently became extinct.
Ferret-polecat
Mustela putorius x Mustela
furo
This widely
kept hybrid was introduced to the isles through accidental or deliberate
release in the 1980s. It has been the subject of an eradication programme
since that time as the species causes considerable damage to ground
nesting birds. Unfortunately it is now feral throughout Mainland although
absent from all other islands.
Mink
Mustela vison
Individuals
were accidentally released from Mink farms in Shetland in the 1960s and
1970s. Although some of the individuals survived for a time there have
been no recent sightings and they are now thought to be extinct.
Otter
Lutra lutra
Although
abundant in Shetland, the otter is one of the most threatened mammals in
Europe where it has disappeared from large areas and become rarer in
others. It was once thought to be indigenous to Shetland but is now
presumed more likely to have been introduced, at least from Viking times,
but actual origin and date of introduction are unknown.
About 14%
of the total UK otter population is found in Shetland - it forms a very
important part of the European total and is of national and international
importance. As Shetland otters are isolated from those elsewhere in their
range, they may also be a genetically distinct race - they are smaller and
have more clearly marked white throat patches.
Otters are found in coastal areas throughout Shetland but one of the
greatest concentrations occurs in the area around Yell Sound. They prefer
low rocky coastlines with shallow water, feeding mainly around kelp beds
on inshore fish such as eelpout, rockling and butterfish. Their holts (hadds)
are usually dug out of soft peaty banks near the shore. Although Shetland
otters spend many of their active hours in and around the sea, their coats
are not designed for prolonged immersion in seawater. To keep their fur
waterproof they must regularly bathe in fresh water burns, pools or lochs.
Photo: Otters -
Bill Jackson
Nature in Shetland
