Natural History in the Highlands and Islands

The whole of the north end of Mull consists of green even terraces with occasional gullies. The islands of Ulva and Gometra are similarly terraced flat cones with occasional gullies. The ground is porous and does not form basins for freshwater lochs; peat is absent. Bracken grows rampant here; indeed, Ulva is almost a museum piece for showing what luxuriant growth bracken can make in the Highlands. On the terraces, only the tips of the horns of Highland cattle can be seen above the fronds, but in the gullies the bracken tries to reach the same height as the plants on the terraces and may grow to a height of 12–15 feet. Trees of many kinds grow well in the sheltered parts of Mull on this soil from the volcanic rock. Just as trees were impossible on the tertiary basalt cliffs of Balmeanach and on Inchkenneth, they reach extraordinary luxuriance and beauty where the calcareous cretaceous sandstone appears again round the edge of Carsaig Bay on the south coast of Mull. This pocket will well repay a visit from the botanist and, I should imagine, from the entomologist. The cliffs to the west of Carsaig are by no means as impressive as at Gribun, but in their face there is to be seen a fine fossil tree fern first brought to the notice of geologists and naturalists by Dr. Macculloch in the early 19th century (Macculloch, 1824). Delicately coloured crystals are also to be found in these cliffs of the south coast.

The south-east end of Mull is dominated by bosses of gabbro called Sgurr Bhuidhe and Creach Bheinn (2,352 and 2,344 feet). From them we may look down on the north side to the long, bare, impressive valley of Glen More and on the south to the tree-lined waters of Loch Uisge and Loch Spelve. The southern peninsula of Laggan, formed by Loch Buie and Loch Spelve and almost made an island by Loch Uisge, reaches nowhere to more than 1,250 feet, but it is extremely rough and rocky, with plenty of scrub birch. Few people have walked through that ground which for many years now has been kept as a small and very private deer forest of 5,000 acres.

The islands of Muck and Canna are both of tertiary basalt on an erosion platform at tide level of lava that looks like clinker. Their soil is so good and their position in the Atlantic so favoured that these islands can grow what are probably the earliest potatoes in Scotland, i.e., May 31. The sheep of these islands do extremely well and come to the mainland in such good order that mainland buyers are hesitant to buy the lambs because they know they have nothing so good to offer them to keep them growing. The wealth of species of insects, molluscs and other invertebrates on these tertiary basalt islands is much greater than would be found on those of the Torridonian or gneiss formations, even though the basalt does not tend to allow lochans to form. The Glasgow University Expedition to Canna in 1936 published a full report of their extensive finds. Muck and Canna both offer the right kind of cliffs for sea birds, and Canna is also a breeding station for the Manx shearwater.

The island of Eigg (Plate 5) is a big shearwater station, the birds nesting well up towards the Sgurr, 1,280 feet. The Sgurr is the most obvious physical feature of Eigg and by far the island’s most interesting natural phenomenon. It is a geological curiosity which has shed light on the geology of other areas far distant. The late Sir Archibald Geikie solved the riddle which Hugh Miller answered unknowingly at an earlier date. The Sgurr itself is of pitchstone, resting on a thin river bed of conglomerate which contains fossil pieces of driftwood from some far distant time. Beneath this is the tertiary basalt again. The pitchstone shows columnar jointing in places, a character which is still more strongly marked on Oidhsgeir, 18 miles away to WNW. This low islet of pitchstone is considered to be part of the same sheet as the Sgurr of Eigg. There is one other feature of Eigg deriving from its geology which should be mentioned here—the musical sands of Camus Sgiotag, a small bay on the north side of the island. These sands are of partially rounded quartz grains of similar size. If the sand is dry a shrill sound is heard as one walks over it.

To return for a moment to the few acres of Oidhsgeir, an islet which does not reach higher than 38 feet above sea level. Here on the top of the pitchstone columns which are 8 inches or so across the top are found the nests of kittiwakes in the season. There are also great numbers of common and arctic terns and eider ducks. Harvie-Brown, visiting the islet several times in the ’80’s and early ’90’s of last century found teal breeding and was convinced that the pintail duck had nested there also. This phenomenon of a small islet in the open sea gathering to it an immense number of living things for the purpose of their reproduction is one to which we shall return in a later chapter on the oceanic island. The deep-cut channels among the pitchstone columns are also a playground for the Atlantic seal. One channel on the south side runs up into a pool where a boat may lie in perfect safety. Many are the occasions when lobster fishers and venturers in small boats have been glad of the quiet pool of Oidhsgeir. What a strange feeling it is to be lying snug in such a place with the mighty ocean pounding but a few yards away and the spray flying over!

The island of Rum, with its three rock types of gabbro, Torridonian and granite, is for the most part a closed book to naturalists. We may hope this unfortunate period of its history is drawing to a close and that it may yet have a future as a priceless wild-life reserve. There are red deer and wild cats on Rum, there are otters round the shores and on the burns, and such species as badgers and roe deer could be introduced if introductions were thought desirable. Some of the finest kittiwake cliffs in the kingdom are to be seen on Rum, and the Manx shearwater nests in holes high up the 2,600-foot hills. The golden eagle is there still, though the sea eagle disappeared during the second half of the 19th century. Given the chance, we may expect the chough to return to Rum.

Skye may be looked upon as the northern outpost of the Lusitanian zone. It has suffered human depopulation like many another Highland area, but Skye is still one of the most heavily crofted areas of the West. Preservation of game has practically ceased and almost all the hill ground is now crofters’ grazing. Topographically, Skye is magnificent, with its Cuillins and its Quirang, but from the point of view of wild life it is somewhat disappointing. The whole area facing the Minch is faunistically poor, as was pointed out by Harvie-Brown fifty years ago.

The island of Raasay, however, between Skye and the mainland, has a surprisingly rich variety of small birds, doubtless as a result of the woods and the large amount of park-like ground which is of Liassic origin. Personally, I should say that the Lepidoptera of Skye and Raasay would repay close scrutiny, not only from the point of view of numbers of species, but from the areas of distribution. Heslop Harrison and his group have already made fruitful researches in this direction. Raasay, like Mull, has its own sub-species of bank vole (Clethrionomys = Evotymys).

The islands of the Atlantic zone are by far the most interesting part. The mainland coasts are often hidden and tend to lose character. But the country bordering the long sea lochs is of exceptional beauty and contains some habitats—such as the indigenous oak woods—which are almost unique in Scottish natural history. To walk the length of Loch Sunart, ten miles out of the twenty through these oak woods, in the fine weather of June is an aesthetic experience, if only for the sight of the redstarts which are here in great numbers. The scenery of the distance is as beautiful as the redstart among the oaks and hazels near at hand. Perhaps the better way is to travel eastwards from Kilchoan and Ardnamurchan Point where the quality of ocean is apparent as on the islands. Sanna Bay on the northward tip of Ardnamurchan is one of the most beautiful shell-sand bays of the West, but it is rarely visited because of its remoteness. East of Glenborrodale the sense of sea is lost and we are in the woods with the loch below us. The peak of Ben Resipol, 2,777 feet, dominates the landscape and is most shapely when seen from this airt. The traveller can hardly miss seeing Ben Iadain, 1,873 feet, and on the other side of the loch in Morvern. It is a little cap of tertiary basalt perched on the Moine schist, but between the two is a very narrow band of chalk. The sight of this little hill cannot fail to impress one with the immense amount of denudation which must have taken place to remove this molten layer of amorphous volcanic rock from so much of this countryside.

Though the oceanic birds such as kittiwakes and auks are lost as one moves up these long sea lochs, it is surprising how many sea birds are to be found breeding in the season. Arctic terns, eider ducks, herring gulls and mergansers—all are here in numbers. And where there are shallow shores and estuaries there are parties of curlews, oystercatchers and ringed plovers. The hillsides above these long sea lochs are almost devoid of heather. The vegetational complex is one of various species of sedge, a few grasses such as flying bent and mat grass, and bog myrtle and deer’s hair sedge. Heather will appear at the edge of a gulley perhaps where the drainage is good. From a distance the most obvious plant may be bracken—great sheets of it, darker green in summer than the herbage and red in winter.

The ecology of the long sea lochs and their intertidal zones is a subject of great interest for those who have the techniques to follow such studies. The gradual increase in salinity from head to foot of the loch, the diurnal variation caused by the tide, the spasmodic variations caused by spates and droughts, the currents formed, and their effects on the life of the waters, still remain to be worked out in detail. Space will not allow of individual description of all the narrow and long sea lochs from Loch Fyne to Loch Alsh: each one has its similarities and distinctions, and certainly each should be visited by the naturalist who is also keen on good country. Most of these narrow lochs have high hills rising from their shores, which means that their south side loses the sun for four months in late autumn and winter. Loch Hourn is particularly sombre in winter because the hills of Knoydart, which reach to 3,343 feet, seem to tower above the loch. Loch Nevis, on the other hand, is sheltered from the north by these same hills, and the North Morar hills to the south of this wider loch do not rise above 1,480 feet. Inverie, therefore, in its sheltered bay on the north side of Loch Nevis, is one of the kindest places in the West Highlands, despite the high rainfall. Indeed, the West Coast is full of these pockets of kindly shelter allowing luxuriant growth. Many of the policies of the large houses have magnificent specimen trees which have grown within a hundred years or so to a size which would have been impossible in a large part of England.

When these sea lochs narrow at their mouth there is a diurnal tide race of considerable force. That at the Corran Narrows of Loch Linnhe runs at 8 knots at ebb and flow, but that at Connel Ferry on Loch Etive is very much more than this and is quite impassable at half tide. When the tide begins to flow here there is the extraordinary sight of a waterfall in reverse, made by the inrush of sea water.

This section may be concluded with mention of the fine piece of country round the shores of Loch Etive (Plate Vb) and up to Glen Coe (Plate 6). Ben Cruachan, 3,680 feet, is one of the landmarks of the Highlands. Cruachan and Ben Starav, 3,541 feet, are of granite and lie either side of Glen Kinglass which runs from the east bank of Loch Etive. There is happily no road through this glen and it is therefore almost untouched. The sides are lightly wooded; the river is of that clarity which is common in waters coming off granite, and as one climbs past the trees and by numerous falls the Forest of Blackmount is reached. This great high place has lost all western character which was expressed at the foot of Glen Kinglass. Blackmount has always been deer forest. Its swan song is that charming book by the late Marchioness of Breadalbane, The High Tops of Blackmount. You may object to all that this great lady stood for, but if you have a fine taste for country and appreciate writing which conveys the atmosphere of particular country you should read her book.

If one makes a cross-country trek from the heart of Blackmount to the head of Glen Etive, a country of high, spiry peaks is reached. What is more, it belongs to the nation. The Royal Forest of Dalness, Buachaille Etive, Bidean nam Bian, and some of the best climbing ground in Scotland is included, and it is probable that adjacent areas will also come under state ownership before long. The botanical and geological interest of the area is considerable, but the student of animal life will find it rather bare. Once more, at the head of Glen Coe we are on the border of our zone. As we look eastwards across the dreich Moor of Rannoch (Plate VIa) it is into Central Highland country.

THE OUTER HEBRIDES OR OCEANIC ZONE

This is the most westerly portion of Scotland, the seventh degree of West Longitude passing down through the middle of this long range of islands which effectually shields the northern half of the West Highland coast. If we study a population map we see that the greater part of the people on the Long Island, as the whole group is called, are fairly densely packed on to the western fringe. Some more dense places are also found on the extreme east of Lewis, as on the Eye Peninsula or Point as it is always called in Lewis. By merely looking at a map one might ask why the people are so densely grouped on the west side where harbours are fewer and where the force of the Atlantic Ocean is unbroken. The very fact of human density of population is surprising to anybody accustomed to the alarming rate of depopulation on the mainland shore of the West Highlands. The Hebridean has a love of home which is unconquerable. There he has remained through thick and thin, sticking to his fringe which is between the mighty ocean and the deadening peat bog of the interior.

The half-million and more acres of the Outer Isles mean nothing in relation to the human population which lives there because to a large extent the interior is just as uninhabitable as the ocean. The people being confined to the coastal fringe live what might be called an open urban existence without town planning.

The overpowering reason for the human species being confined to this fringe is that here the awful blanket of peat ends and the ocean has thrown up an immense weight of shell sand. As the dunes have stabilized through the millennia and the stiff marram grass has given way to kinder herbage, a light lime-rich soil has formed. There are miles and miles of the white sand on the Atlantic shore, and above it the undulating machair (Plate XIXb) of sweet grass on which are reared great numbers of Highland and cross cattle. Flocks of barnacle geese come to the machair in winter and add to the humus content of the sandy soil. The prevailing south-westerlies continue to blow winter and summer, year after year, century after century. The tangle from the shallows of the ocean, the various Laminarias of the marine botanist, is torn from its bed and washed up on the beaches. Man comes down with his ponies and carts and creels and takes up some of it to spread on ploughed portions of the machair. All these things are helping to make soil, and the sand itself in these gales, especially if the winds are dry, is being blown up towards the blanket of peat which overlies the archaean gneiss of the Hebrides. The sand sweetens the peat, causes its barren organic matter to be unlocked and become fruitful of herbage for man’s beasts. Their dung still further ameliorates the peat. Such is the constant process, in which the storm is a necessary and beneficent factor in allowing and maintaining fertility. But once the coastal strip is crossed the peat reigns supreme. Its blanket must have increased about ten feet since early man came to the Outer Isles, for only the tops of the fine Megalithic stones at Callernish, Lewis, were showing when Sir James Mathieson of the Lews undertook their excavation. The landscape in the bog is shortly described—a low undulating plateau of peat, bare grey rock of gnarled shape, and thousands of small and large lochans of brown acid water. If we wander through these areas of peat we shall come upon drier knolls where the rock comes to the surface or is not far beneath, and here we shall find turf and greenness for a space. The shielings of Lewis have been and still are here. They are the summer dwellings of a pastoral people taking advantage, for their cattle and sheep, of the short spell when the peat grows its thin crop of sedge and drawmoss. The people lived on the little knolls as on islands, bringing their cattle up to them twice a day for the milking; throwing out their household waste—little that it was—and adding their own quota of dung and urine. The shieling life is mostly gone but the green knollies in the sea of rock and peat remain.

We may digress at this point to consider the nature of peat, this substance which covers a million and a half acres of the Highlands and Islands and the existence of which is a most important factor in the natural history of the area and of the scenery. A study of the peat is interesting not only for what it grows and harbours now, but for the history to be deduced from a deep profile of it. Peat forms under the influence of certain definite conditions and their consequences: the first requirements are high precipitation and a general coldness of atmosphere in the growing season sufficient to inhibit bacterial activity in the waterlogged soil, but not cold enough to prevent growth of certain plants. A vegetational complex of sour bog plants, such as sphagnum moss (Plate 22b), sedges of various kinds and cross-leaved heather, soon occupies the ground to the exclusion of all those plants which need a well aerated soil and a supply of basic compounds. The rain impoverishes the original soil by washing out plant foods and then, by creating waterlogged and therefore anaerobic conditions, prevents the action of normal soil bacteria in breaking down the dead vegetation into humus. Such necessary decomposition does not keep pace with vegetative production by the plants, so that a gradually thickening layer of peat forms. The peat, thus composed of organic matter without lime, is highly acid in character, which is a still further check to bacterial action. Even the run-off water from the poor rocks such as gneiss and Torridonian is charged with unneutralized carbonic acid. With compaction and age, the peat becomes colloidal in texture, a fact of much influence in the behaviour of peat in holding water or being dried. The normal water content of peat as it lies in the bog is as high as 93.5 per cent.

Peat varies in consistency from being highly fibrous to the state of a black amorphous substance, depending on age and the type of vegetation. The Highland crofter is well aware of these details and his methods of winning peat for fuel vary from place to place. Cottonsedge peat is tough and fibrous and can be “footed” (i.e. set up on end to dry in pyramids of four bricks) and handled later with very little loss. Lower, older, amorphous peat is very brittle and cannot be set up.

The ages of the peat deposits have been tentatively fixed as beginning about 7000 B.C. at the close of the Boreal period. The warmish dry climate which grew forests of pine, birch and hazel now became warmish and wet, bringing about destruction of the scrub hazel vegetation by moss. The Atlantic period closed between 5000 and 4000 B.C. and a cooler and somewhat drier sub-Boreal period set in with a rapid development of peat. This continued until near our era which may be termed cold and wet and sub-Atlantic. The peat to-day is still making in some places as on the main bog of Lewis, and receding in others, as in parts east of the Cairngorms where the stumps of forest trees are coming forth as the peat crumbles away. Continual burning on western hills is probably having more influence than we know in checking or denuding the peat which is the only cover the rocks have, but in Lewis there is very little burning, the slopes are gentle and the succession of blanket bog is not being much disturbed, except by cutting for fuel.

The colours of the Atlantic coast are vivid blues and greens and the bright cream of sands. Inland, sombre colours are paramount and the lochans do not reflect the colour of the sky from their dark depths as does the sea above its floor of white sand. But the Hebrides are not all a dark plateau. The southern end of Lewis (Plate VII) and most of Harris are hilly. The Forest of Harris gives us rough going as anywhere in the Highlands and the Clisham rises to a fine peak of 2,622 feet. The red deer which live in these fastnesses are small, but have very well-shaped heads. The pine marten was also to be found there until recently. Its very wildness is the best protection this piece of country has. The lower deer forests of Park and Morsgail are fairly heavily poached of their deer, in an island of such heavy human population.

The Hebridean burns a lot of peat. His peat stacks are far larger than those of the mainland. By cutting peats he is doing two jobs—providing the wherewithal for comfort at the fire, and removing some of the great pervading blanket. He does not come upon bed rock at the foot of the peat banks but on to a layer of boulder clay which, when mixed with the top thin layer of sedge and peat, will shortly turn into fairly good soil providing much better grazing than anything from the top of the peat. The boulder clay came there by glacial action before the peat was laid down. Our Lewisman makes new ground this way and there is no doubt that if the modern mechanical tools such as the scraper and bulldozer were brought into operation on what is commonly called the skinned land, the agricultural scientist could make much good land in Lewis without attempting to conquer the upper layer of the peat.

As might be expected, the bird life of the interior of the Outer Hebrides is poor in variety and scanty, the nesting grey lag geese and red-necked phalarope (Plate XXXIIa) being probably the most interesting members. The geese feed on the crofting ground and on the machair but return into the maze of the interior to nest. The coasts are rich in sea birds, ducks and waders.

The Outer Hebrides are often described as being treeless, but the term is relative. The people who write about them are usually those who have a considerable experience of trees and tend to take them for granted. The Outer Hebrides are neither treeless, nor need they continue to be so desperately short of trees as they are. The grounds of Stornoway Castle on the east side of Lewis are famous. There are hundreds of acres of trees here, mostly conifers, but with a fair sprinkling of hardwoods and deciduous trees. These are Lady Mathieson’s legacy to the Hebrides. Indeed, it needed courage to start tree-planting from scratch. She planted another piece with larch and other conifers half-way across Lewis, near Achmore, and these made good trees, but were blown down by a terrific gale on March 16, 1921. There are 90-year-old Corsican pines of hers at the head of Little Loch Roag, growing quite straight to 35 feet high. There is another plantation of deciduous and coniferous trees at Grimersta on the Atlantic coast of Lewis. Another plantation of conifers sheltering a house, Scalisgro, on the east side of Little Loch Roag, is less than twenty-five years old, and twelve years ago several acres of conifers were planted in Glen Valtos in the Uig district of Lewis. Sycamores are the great standby of a tree lover on an ocean coast. Several good ones are to be seen at Tarbert, Harris. And at Borve on the west side of Harris there are several acres of stunted mountain pines. More trees are to be found about Ben More Lodge in South Uist, and there are a few more in the north glen of Barra. Heslop Harrison has recently drawn attention to the birch wood, complete with bluebells and wood sorrel, on the slopes of the Allt Vollagair, South Uist. As has been mentioned already, many of the islands in the Lewis lochs are covered with dwarf rowans. That the Outer Hebrides were once a wooded area may be deduced on archaeological grounds as well as on the living relics. Baden-Powell and Elton (1936–37) excavated an Iron-Age midden at Galson on the north-west coast of Lewis. They found bones of wild cat and blackbird among the refuse, both creatures of woodland and savannah. The age of the midden was reckoned at 1,500 years or thereabouts.