Natural History in the Highlands and Islands

The splendour of the Torridonian is in the peaks it makes inland. Some are fantastic and others superb. There is only one Suilven and it is undoubtedly the most fantastic hill in Scotland (Plate 3b). It rises to 2,309 feet out of a rough sea of low gneiss. Seen from north and south it has a distinctive shape of a very steep frontal cliff and rounded top called Casteal Liath (the grey castle), then a dip and a lesser knob before a more gentle slope down to the east. But when seen from west or east the extreme thinness of the hill is apparent. Probably the Dolomites would be the nearest place where such an extraordinary shape of a hill could be seen. Suilven means the pillar which is a good name for the hill seen from the west. It is often likened to a sugar loaf, also. There are greyish-white quartzite boulders sprinkled on the top, yet there is a little alp of grass up there and an occasional bed of Rhacomitrium moss. The great terraces of Caisteal Liath itself are but thinly marked by such grasses and sedges as Festuca ovina forma vivipara and Luzula spicata as can send their roots far into the cracks.

One of the striking things about the Torridonian peaks of the far north-west is their isolation, caused by the vast denudation which has taken place, leaving these few hard cores of sedimentary rock overlying the wilderness of gneiss hillocks and innumerable lochans. The term hard core is here being used metaphorically and not geologically. North of Suilven and Loch Assynt is the massif of Quinag, five conical peaks capped with quartzite, with a fine rampart of cliff and scree on the west side, which is nearly three miles long. The massif is no higher than 2,653 feet, but how much more impressive is it than half a hundred three-thousand-footers in the Central Highlands! South of Suilven there is Cul Mor, 2,786 feet, surrounded on three sides by great precipices; and Stac Polly, 2,009 feet (Plate 4b and Plate 10) the narrow ridge of which is like one of those fairy castles of childhood tales perched on the top of steep slopes. Ben More Coigach rises to over 2,000 feet in under a mile from the sea as the crow flies. The air of this countryside with its lower rainfall is generally much clearer than farther south in the Highlands and adds to that sub-arctic quality which characterizes the area.

Before leaving this far northern corner, the ranges of Foinaven, 2,980 feet, and of Ben More Assynt, 3,273 feet, must be mentioned. The group culminating in Foinaven is without doubt the barest range in Scotland, and composed of that unyielding white rock, the Cambrian quartzite. The northern part is like a giant E, the crossbars being ridges peppered heavily with boulders which form screes again below the shoulders: the hollows of the E are fine corries on the slopes of which the snow bunting has bred. The southern part is a horseshoeshaped ridge of which Ben Arkle, 2,580 feet, is the western rampart. This hill of Cambrian quartzite with its banding of white scree may be viewed to perfection from the highroad on the shores of Loch Stack; but for the greatest glory of this range a six-mile trek must be made to reach the vast horseshoe corrie and Loch an Easain Uaine, the loch of the green falls. It is well to rest here awhile and realize that the pine marten is probably commoner in this neighbourhood than anywhere else in Britain, to remember the snow bunting up in the tumble of boulders and possibly see him feeding on the buds of Saxifraga oppositifolia. The alpine species of plant creep far down these bare hillsides and one wonders what there is here to recompense the deer for the energy used in attempting to graze these slopes. The boreal affinity of this range was further emphasized by the occurrence of alpine butterwort (Pinguicula alpina), which was found nowhere else in Britain but on the high tops of Sutherland and Ross; unfortunately this species may now be quite extinct, as it has not been found since 1900, according to Druce’s Comital Flora. The same authority puts 1794 as the last date on which this plant was found in Skye.

Ben More Assynt itself is a solid quartzite cap with igneous intrusions set upon a mass of Lewisian gneiss. There has been a series of geological overthrusts in the region, in which tumults areas of limestone have come to the surface. This limestone has affected the natural history of the whole region, causing a wealth of crustacean and other aquatic life on the waters affected by the limestone, differences in the temperature of the water of some streams which suddenly rise from the rock, allowing the formation of water-worn caves in which have gathered soil and bones of animals of earlier times. Such organic remains are rare in the Northern Highlands.

The comparatively low ground of all this northern region of the gneiss, so difficult of access and so plentifully strewn with lochs, is also a place where sub-arctic birch scrub (Plate IV) is common and there is a certain amount of hazel. There are large stretches of birch in Inverpolly Forest (Plate 4b) in the vicinity of Loch Sionnascaig, which is one of the most beautiful lochs in the whole Highlands. There are pristine birch-wooded islands in the loch where the grey lag goose bred not so long ago and where the pintail duck has bred recently. There is more birch round Lochinver and below the north face of Quinag, and many a stretch may be found on the hill far from the roads, in places which are almost unknown to the naturalist. Some day we may find the redwing building in these woods, for this bird has been heard singing here from time to time in April, and the redwing is essentially a native of the sub-arctic birch wood.

The eastern side of the extreme Northern Highlands is given up to extensive sheep-farming. The hills are of no great height and are of easy slope. The herbage is sweet and good. The largest sheep farms in Great Britain are here, some having upwards of 10,000 ewes. The breed kept is the Cheviot of the distinctive lustrous-woolled Sutherland type. The lambs are sold annually at the great sales at Lairg. No man was more responsible for the development of Cheviot sheep-farming in the North than Sir John Sinclair of Ulbster, in the 1790’s. The influence of sheep-farming on the natural history has been profound and will be given special attention in a later chapter.

This far northern area has been treated at some length, because it is the most remote part of the Highlands and one of which detailed studies in natural history have been rare. It may be recommended as an exhilarating and fruitful field for exploration.

South of Loch Broom, the Torridonian hills are more thickly grouped and reach their highest peaks. Their spiry form and the high corries facing to the east are distinctive. The quality of herbage is generally poor and the terraces formed in the lower reaches of the Torridonian hold up the heavy rainfall so that it is often quite impossible to get about dryshod. How different is the nature of the ground from those smooth dry slopes of glacial sand and gravel which are such a marked feature of the Central Highlands! The differences brought about in the vegetational complex have not been sufficiently stressed by plant ecologists in the past. The ground has not been well walked through and explored as yet.

There are two high hills of the Torridonian which have north-eastern corries quite the most magnificent of their kind and few who have seen them both can decide which is the better. This in itself should show how similar are such groups of hills and the forces which moulded them. I allude to An Teallach of Dundonnell (Plate IIIb and Plate 4a), 3,485 feet, and Beinn Eighe, 3,456 feet, between Kinlochewe and Loch Torridon. Each of these hills has three corries facing NNW. to NE. Coire Mhic Fearchair is the most westerly of the corries of Beinn Eighe, and the Toll Lochan corrie of An Teallach is the easterly one of the range. Some of the buttresses in Coire Mhic Fearchair are exceptionally fine and the corrie makes an almost perfect horseshoe, but for myself I think I prefer the Toll Lochan corrie, for the cliff face at the head of the lochan is of greater depth and of superb architecture, nearly 1,800 feet of it.

Between An Teallach and another corried Torridonian peak, Beinn Dearg Mor, 2,934 feet, is the broad amphitheatre known as Strath na Sheallag, at the head of Loch na Sheallag, from which the Gruinard River runs. This strath is beloved of the deer, and though so remote it draws cattle, sheep and ponies to it from far away. Just as An Teallach has Beinn Dearg Mor as an outlier, so has Beinn Eighe her Beinn Dearg, 2,995 feet, almost a replica of its cousin of Strath na Sheallag. Liathach, 3,456 feet, Beinn Alligin, 3,232 feet, and Slioch, 3,217 feet, these are just three more of these splendid Torridonian peaks—clear of peat from 1,750 feet upwards and often topped with a white cap of quartzite boulders. The sudden change from wet peat-laden terraces to the upper slopes of bare rock, or thin covering of brash and alpine vegetation, results in a sharp snow line in winter which gives these hills a special seasonal beauty. This sudden cessation of the peat immediately allows a different flora, one of plants which can withstand droughts and sudden changes of humidity, and which prefer sweeter conditions than are possible on peat. Here and there among the alpine poa grass and viviparous sheep’s fescue are straggling plants of dwarf juniper, clinging close to the rock. Sea pink and thyme are also to be found on the gravel. Eagle, peregrine falcon and wild cat abound in this country, and as it is all deer forest and not grouse moors of any consequence, the eagle is allowed more sanctuary than it has been given farther south and east.

The glens of the Torridonian area of the North are often well wooded. They have been owned by people with a fair (or perhaps unfair!) measure of worldly riches, who have been able to spend a good deal of money on planting for amenity. Take Dundonnell for example, at the head of Little Loch Broom: the loch side is bare of trees and is given up to crofting townships, but soon after the head of the loch is reached one is into a fine wooded glen. There are a few hundred acres of Scots pine of greatly varying density stretching up the southern side to an altitude of 1,000 feet. There are alders, oaks, rowans, and hazels along the river bank, and some hundreds of acres of birch at the head of the glen reaching up to 1,500 feet. But all round the cultivated strath and the house which was built in 1769 there are signs of planting for beauty: limes, many fine beeches, sycamores, ashes, elms, oaks, chestnuts and big old geans; and until a few years ago there were many acres of fine larches on the north side. The wild life of such a glen is obviously profuse and varied. We have these men of a past age to thank for planting that which we now enjoy, just as we may blame those of a century earlier who were denuding the Highlands of timber.

Loch Maree is another place where there are some very fine woods, but here the sub-arctic quality of the northern zone is being lost and replaced by the complex of sub-alpine vegetation. Near where the Ewe River from Loch Maree goes into the sea in Loch Ewe there is a famous garden which grows a great variety of rhododendrons and azaleas and many sub-tropical plants and plants from Oceania. This is just another facet of the Highland paradox, the garden at Inverewe lying between the stark precipices of Ben Airidh Charr and the bare windswept slabs of Greenstone Point where the sea is never still. And if I may add one more touch of paradox, I saw a kingfisher on the rocks at Greenstone Point at the edge of the tide, one September day.

CHAPTER 3

RELIEF AND SCENERY (continued)

THE WESTERN HIGHLANDS OR ATLANTIC ZONE

SOUTH of Skye the coasts of the West Highlands fan out much more than to the north of that island. Indeed, there are several considerable islands reaching out into the Atlantic. The Outer Hebrides are not masking the influence of the Atlantic on this area as they do on the north coast of Skye. The influence of the Atlantic Ocean on this zone is both direct and inhibitory, and indirect and encouraging to a wealth of plant growth. The island of Islay, for example, changes character completely between its western and eastern halves. On the Atlantic side there is the lack of trees and shrubs and the presence of short sweet herbage salted by the spray from innumerable south-westerly gales, whereas there are beautiful gardens, palm trees and some forestry on the south and east sides. The Rhinns of Islay on the Atlantic coast are not heavily covered with peat as is a good deal of the eastern half. Islay is an island of many good arable farms, and it has several square miles of limestone country.

The waters of the North Atlantic Drift cast up on these Atlantic shores pieces of wood and beans of West Indian origin, and plants such as the pale butterwort (Pinguicula lusitanica), pygmy rush (Juncus pygmaeus) and the moss Myurium Hebridorum which occur again on British coasts only in the south-west, here turn up in fair numbers. The pale butterwort occurs in the bogs of Portugal and western Spain, and on the west coast of France; Myurium moss is found in the Azores, the Canaries and St. Helena as well as in our Outer Isles. Dwarf cicendia (Cicendia pusilla) has also turned up in this zone, though previously found in the British Isles only in the Channel Islands. More recently, Campbell and Wilmott (1946) have found another Lusitanian plant in Stornoway Castle park, namely Sibthorpia europaea. The work of Professor Heslop Harrison and his group from the University of Durham should be consulted. It is his opinion that these western cliff edges escaped the last glaciation and thus their Pleistocene flora was not exterminated. Others hold that the flora must have been introduced since then.

Jura is not so well served with the rich quality of vegetation we may find in Islay or even in small Colonsay and in Mull. It is composed of quartzite, which is poor stuff. Jura is also heavily covered with peat and suffers in consequence. A thick blanket of peat has a very great depressing effect on the variety of vegetation and in limiting the growth of deciduous trees. Jura is an island of high hills. The Paps rise to 2,571 feet and are quite rough going. It was on these hills that Dr. Walker of Edinburgh in 1812 conducted his classic experiment on the differential boiling-point of water at sea level and at the top of the Paps. Jura has a very small population of human beings on its nearly 90,000 acres. The island is so poor that its long history of being a deer forest will probably continue. In mythological literature Jura appears as being uninhabited and a place where heroes went a-hunting. It was on Jura during the latter part of the 19th century that Henry Evans conducted careful studies on the red deer. His were the first researches of a scientific character on Scottish red deer, yet he never set out to be more than a scientific amateur.

The island of Scarba, of about 4,500 acres, high and rocky, lies north of Jura. The Gulf of Corrievreckan is in the narrow sound between the two islands. This celebrated whirlpool and overfalls is caused by the strong tide from the Atlantic being funnelled through a strait, the floor of which is extremely uneven. The sound is quiet at the slack of the tide but is dangerous to small craft when the tide is running. The largest whirlpool is on the Scarba side of the sound, but there is a spectacular backwash on to the Jura coast which used to be reckoned very dangerous in the days of sailing boats. The maximum current is probably about 81/2 knots which is very fast for a large bulk of water. No herring drifter or ordinary motor fishing-boat could hope to make headway against such a current, for their maximum speed in calm water is not more than 10 knots.

This West Highland zone has what the North Minch lacks, a number of sizable islands which are not big enough to lose their oceanic quality, and not so small that they are utterly windswept. The islands of Colonsay and Oronsay, west of Jura, are an excellent example of islands which have the best of almost all worlds. Naturalists may be glad that Colonsay is in the possession of one who recognizes its value and beauty in the natural history of the West. Most of the island is of Torridonian sandstone of a different complex from that farther north, but there are overlays here and there of limestone and its derivative soil, and the 100-foot beaches are another place of good soil. There are sand dunes, cliffs and rocky beaches where several rare maritime plants are to be found. There are fresh-water lochs with water lilies and the royal fern in profusion. Natural woods of birch, oak, aspen, rowan, hazel, willow and holly also occur, and beech has been planted. The sight of these, so near the Atlantic and its gales, may be imagined from this short passage from Loder’s exhaustive book:

“The woods are being rejuvenated by young plantations of Birch and Aspen, which are springing up naturally and contending for supremacy with an annual luxuriant growth of bracken. The Woodbine twines over the trees, and festoons along the edges of the numerous rocky gullies that cut up these slopes. Ivy has climbed up and formed pretty evergreens of the more stunted of the forest trees. The Prickly-Toothed Buckler Fern grows in profusion, and the little Filmy Fern is also to be seen under mossy banks.”

There has been considerable planting of coniferous and deciduous trees for amenity in this Atlantic island so that it now presents a luxuriant and well-wooded aspect in the neighbourhood of the house. But in gazing on these woods now and noting Colonsay’s wealth of small birds, we should remember the effort entailed in beginning to establish these conditions. Loder says:

“When planting in the island first began, the trees made so little headway that it was considered amply satisfactory if they formed good cover. For the first ten years or so they made little progress, and many places had to be planted over and over again. Protection from animals and weather was provided in the first instance by dry-stone dykes, 5 feet high. Alder and Sea Buckthorn were planted along the most exposed edges. Alders and various species of Poplar were used in wet situations but the poplars did not last well, and were liable to be blown over. It was only as the trees made shelter for each other that they began to show any vigorous growth. Indigenous species such as Birch, Oak and Rowan, have sprung up on hilly ground where the planted trees failed to establish themselves.”

The trunks of trees in these Atlantic places tend to become covered with lichens such as Parmelia perlata and Usnea barbata, and mosses such as Eurhynchium myosucoides (on birch), Ulota phyllantha, Hypnum cupressiforme and Brachythecium rutabulum. These trees seem to be much more affected by the humid climate than such exotics as Escallonia, Ceanothus, Verbena and Mimosa (Acacia) which grow luxuriantly. This is one aspect of Colonsay, but there are also its sedgy and heathery moors like those of many another island of the West, and at the southern tip, where the Atlantic has full play over the Torridonian and mudstone slabs gently rising from the sea to make platforms and pools near the tide level, the Atlantic grey seal breeds in fair numbers. Elsewhere, on the cliffs, kittiwakes, razorbills and guillemots breed; and there are three species of tern, arctic, common and little, breeding on the island.

Colonsay and Oronsay together might well be looked upon as an epitome of the West Highland world in its full range and consequences of Atlantic exposure and sheltered mildness.

Farther to the north-west are Coll and Tiree, two more islands which receive practically the full force of the Atlantic, but which show decided differences in natural history. Tiree is very low indeed. The rocky portion of the island, of Lewisian gneiss, reaches its highest point in Ben Hynish, 460 feet, but by far the greater part of Tiree (Plate 25) is but a few feet above sea level and composed of blown shell sand resting on a platform of gneiss. The island is one of good-sized arable crofts and is so far different from most West Highland districts that it has a Clydesdale horse-breeding society of its own. The sandy pastures of Tiree are deficient in cobalt but recent researches in mineral nutrition of animals have allowed the farmers of Tiree to dress the land with as little as 2 lbs. an acre of a cobalt salt and prevent the onset of pine in sheep. The island has particular interest for the birdwatcher: first, it is on a migration route and gets both summer and winter visitors which would not be seen anywhere in the North Minch, and its rich arable land also attracts a large number and variety of birds. Loch Vasapol of Tiree is a famous place for various duck. Tufted duck breed there and the gadwall is found there in winter though so uncommon elsewhere in the West. The vast beaches encourage certain waders, including the bar-tailed godwit, sanderling and greenshank. In the past the snipe-shooting was reckoned the best in Europe. Happily, there is less of it now.

Glacial action in Tiree is shown by the Ringing Stone, a huge rounded boulder of augite which probably came to rest there after a journey in the ice from Rum. The stone is marked by many ringed hollows on its surface.

The island of Coll, once one is within it, reminds one of the low gneiss country of Sutherland. Here the innumerable little hills are still smaller than in Sutherland and not so steep, none rising above 339 feet. The island presents a uniform rocky appearance when seen from a distance on the east side. On the west side of Coll are miles of shell-sand dunes, a feature which tends to be characteristic of many of the islands which meet the full force of the Atlantic and are low enough to have allowed the sand preliminary lodgment. The interior of Coll is just peat where it is not bare gneiss, yet with its western pastures it has always had the reputation of being a good place for cheese and sound dairy cattle. This island is important for the student, of distribution of plants in relation to the last glaciation and associated changed ocean levels.

The low, sandy islet of Gunna lies between Coll and Tiree. It is a great place for Sandwich, common and arctic terns and I believe the little tern nests there too. Such burrowers as the sheld-duck are plentiful, of course. Barnacle and grey lag geese are common in winter.

The small group of tertiary basalt islands known as the Treshnish Isles lie between Coll and Mull. The most southerly one has a rounded cone of an old volcano, 284 feet high, which gives the island the name of Dutchman’s Cap (Plate Va). The middle island of the group, Lunga, also has a volcanic mound rising to 337 feet, but the other small islands are all flat-topped with sheer sides of amorphous basalt resting on a platform of lava. This platform is of great importance in the natural history of the Inner Hebrides because it makes a breeding ground for the Atlantic grey seal. The Treshnish group, especially the Harp Rock of Lunga (Plate XIXa), is a nesting place of kittiwakes and auks and fulmars. Storm petrels nest in the Treshnish also, and the Manx shearwater on Lunga at least. The quality of grass on these islands is excellent and attracts a vast flock of barnacle geese in winter. The green rich grass of the islands is reflected again in the presence of large mixed flocks of starlings and peewits. In winter-time hundreds of blackbirds and a good many thrushes live on the Treshnish group. Lunga, being infested with thousands of rabbits, has a stock of seven buzzards.

The Cruachan of Lunga will be a good place to rest for a few moments and look at the topography of Mull, that very interesting member of the Inner Hebrides, Mull of the Mountains as the Gael calls it. The eye is first struck by the shapely peak of Ben More, 3,169 feet. This is the highest point reached by the tertiary basalt in Scotland. The cone itself is the result of great weathering, and the various beds of this amorphous lava are evident now in the truncated edges of the lower slopes of the hill. For sheer hard going, the descent from the summit to Loch Scridain takes a lot of beating, for the traveller is constantly having to make his way round these faces of rock which are not readily obvious to him as he comes down the hill. The terraced quality of Mull is obvious in a large part of Loch Scridain, the terraces being exactly the same height on either side. The peninsula between Loch Scridain and Loch na Keal reaches on the north side a stretch of some miles of very fine cliffs with sweeping talus slopes at their foot. The cliffs of Balmeanach are to my mind one of the striking features of Mull. The 1,600-foot basalt cliffs have trapped the cretaceous sandstone layer beneath them. The cretaceous sandstone—the local representative of the chalk—may be found in a narrow stratum just above sea level. These cliffs are difficult to explore and remain largely unexplored. Down below, the small island of Inchkenneth, the burial place of old Scottish kings and chieftains, is also composed of low strata of this cretaceous sandstone. If there is anywhere where chimneys must have cowls it is on Inchkenneth, for the down draughts from the great cliffs in a south wind are tremendous. Slates have to be specially cemented on the roofs. Corn and hay stacks suffer badly in this abnormal situation.