The Romans knew them as the Ultima Thule –
The Edge of the World. They lie at the same latitude as the southern part of
Greenland, straddling 60oN. Although the climate is officially
described ass equitable, due in large part to the ameliorating effect of the
warm North Atlantic Drift, they are one of the coldest (mean July temperature
some 10oF lower than London), wettest and windiest places in the
United Kingdom. They are the northernmost and remotest part of the British Isles.
They are the Shetland Isles. Not it would seem the ideal destination for a
summer break.
However, it was to Shetland I headed for my
summer holiday in 1983, as I had done for the previous six years. The lure of
the islands is their natural history, particularly for me, the bird life. On my
previous visits I had been a member of the Leicester Polytechnic Shetland
Expeditions monitoring the wildlife in the approaches to the Shetland Oil
Terminal at Sullom Voe, that is the east and west coasts of Yell Sound and the
Yell Sound islands. I have carried out breeding bird surveys and helped with
the extensive bird ringing programme. Other work of the expedition includes
monitoring permanently marked seashore transects, the continuation of some of
these transects underwater by a team of divers, plus botanical and
entomological studies on land. The aim of the expedition is to produce a base
line against which the effect of any environmental accident, e.g. an oil spill,
can be measured.
Most of my studies have been concentrated
on one species, the Red-throated Diver. It is almost exclusively marine in its
habits and only comes to the freshwater lochs and lochans to breed. Even then
most of its feeding is done at sea. It is well adapted for the marine
environment being very streamlined and having its legs set well back along the
body for better movement through the water. This makes it clumsy on land and
its nest is usually placed within a few feet of the water’s edge. Censusing is
relatively straightforward as adults with eggs can usully be observed on the
nest and adults with young can be seen on the water. These observations can be
made from some distance so reducing disturbance to a minimum. This ease of
censusing makes it a good monitor species for the state of the marine
environment.
This year (1983) the Royal Society for the
Protection of Birds (RSPB) was conducting a complete census of this species in
Shetland. This meant visiting every water body on the islands twice, to ensure
no breeding attempts were missed, during the main part of the breeding season.
A look at the Ordnance Survey 1:50000, or better still the 1:25000. Maps shows
what a mammoth task this was. I was asked by the RSPB to be a member of the
team, but work commitments meant I was only able to join for three weeks in
July.
Inspecting every loch and lochan involves a
lot of walking over the desolate interior of the islands. The terrain is mostly
gently rolling peat moorland where walking is made difficult by the erosion of
the peat into deep gullies amid the sphagnum bogs. It is impossible to walk in
a straight line. Despite the hard slog, it had its compensations, I saw a lot
of Shetland from the northernmost point of Hermaness on the island of Unst to
the highest, Ronas Hill on the mainland. The inland scenery is not particularly
inspiring but as nowhere in Shetland is more than three miles from sea, almost
any hill top will give wide views over the archipelago showing many islets in
the sounds between the main islands and the long thin inlets known as voes or
firths, scaled down versions of the Norwegian fjords. The coastal scenery is
some of the most impressive in the British Isles with cliffs soaring to over
300m in places plus many caves, stacks and natural arches.
And, of course, there are the birds. The
moorlands of Shetland are the breeding grounds for a variety of species
including Curlew, Dunlin, Common Sandpiper, Greenshank, Merlin and Twite. Shetland
is also the British stronghold for breeding Whimbrel, Arctic Skua and Great
Skua, 25% of the world population of the latter breeds in Shetland. The Great
Skua, or Bonxie as it is known in Shetland, is one of the more obvious birds of
the moorland. They nest in loose colonies where the adults can be seen standing
guard on small hummocks over-looking their territories. On the approach of any
intruder, man or beast, they take flight and mob the trespasser. This takes the
form of a dive-bombing run: starting high, they power dive almost vertically,
slowly lessening the steepness of the descent until they are travelling
parallel to the ground at high speed and at about eye-level. The intensity of
the attacks increases as the nest or chicks are approached. It is quite an
experience to have a large gull-sized bird bearing down on you at great speed and
a test of nerve to stand there without flinching.
Not all of my time in Shetland was spent
stomping across the moors censusing Red-throated Divers, although most of my
time was spent bird-watching. I visited the huge seabird colonies at Noss and
Hermaness where millions of cliff-nesting seabirds breed. Most impressive of
these is the Gannet. The adult is a large white bird with black wing tips and a
cream-coloured head which glides effortlessly about the cliffs, using the wind
to great effect. It feeds with spectacular plunge-dives, dropping from a great
height on half-closed wings. Probably everyone’s favourite is the Puffin which
nests in burrows near the cliff top. Although wary, they often fly away at
first, but they are also inquisitive and may approach within a couple of feet
of the patient observer. The overall sensation of the seabird city is one of
constant movement with birds coming and going wherever you look. While at
Hermaness I also visited Albert Ross, a well known but somewhat lonely summer
resident of the cliffs.
On several occasions I went out
bird-ringing (banding) with the Leicester Polytechnic Shetland Expedition. One
of the main target species is Storm Petrel. These are small, black seabirds
with a white rump which nest in hollows among rocks. Their natural nest site is
scree on the cliffs but they have taken to using dry stone walls and the
remains of Pictish brochs. They only come ashore at night as they a quite weak on
land and would be easy prey for the marauding gulls and skuas. The expedition
ringing teams are out every night, weather permitting, using mist nets to catch
the Storm Petrels. It is not necessary to go to the colonies as the birds can
be attracted by playing an amplified recording of their calls. It has been
shown that only young, non-breeding birds are attracted in this way and even
when close to a known colony few, if any, breeding birds are caught. The mist
nets are set up at a suitable site where there is some protection from the
elements and the wind is blowing offshore, to carry the amplified calls. The
first Storm Petrels are usually seen just before midnight and catching
continues through the darkest part of the night until about 02:00 by which time
there is usually enough light for the birds to see the net. It is possible to
catch more than 100 birds per night, depending on the weather conditions, and
occasionally there is the added bonus of trapping the rarer Leach’s Petrel. All
birds caught are weighed, measured and have a uniquely numbered metal band put
around one leg which enables them to be identified should they be re-caught.
Shetland has a lot to offer naturalist,
including many more bird species than I have mentioned above. There is also
much to interest the archaeologist, botanist and geologist, but little to offer
the sun seeker, although this year, for the first time, I spent two whole days
in shorts and t-shirt. Usually the regulation wear os thick jumpers and
cagoules! I hope to return to Shetland next year and continue my studies of
Red-throated Divers.
By the way Albert Ross is a lone
Black-browed Albatross which has take to nesting among the Gannets at Hermaness
– although with no mate this must be a frustrating experience.
Recommended Reading: The Natural History of
Shetland. New Naturalist Series.
