Читать книгу Natural History in the Highlands and Islands - F. Darling Fraser - Страница 17

THE HUMAN FACTOR AND REMARKABLE CHANGES IN POPULATIONS OF ANIMALS

IT IS of the very nature of humanity to alter the complex of living things wherever man is found. Man must be considered as part of the natural history of the earth’s surface, however unnatural he may be. Of course, all animals alter the rest of the complex of living things in some way or other, but none does it with reflective intention as man does, and, I might add, none does it with much less regard for consequences. The animal, lacking the power of reflection, is as much at the mercy of its environment as the environment has to endure that particular animal; but man has power quite beyond his own physical strength; he can make the desert bloom, or ultimately fill an oceanic island with the beauty of bird song, and equally he makes deserts as spectacularly as any horde of locusts.

What has man done to the Highlands and Islands and what is he doing? Something of that story will be discussed in this chapter, but not so much as might be desired. Professor James Ritchie, now Regius Professor of Natural History at Edinburgh, has written a large volume entitled The Influence of Man on Animal Life in Scotland. It is an interesting and often depressing story, but Professor Ritchie would probably be the last to suggest that he has told the complete tale. There is much of the story we do not know or are only just learning how to infer and deduce. And our methods of recording are never complete enough to mark down, for future minds to work upon, the doings of the present generation of men.

Scotland, and the Highlands particularly, have nothing like such a long human history as England has. The last glacial epoch prevented that, for Scotland was under the ice thousands of years after man had inhabited the south of England. The tradition apparently established at that time has persisted with remarkable tenacity, because many people still seem to think that the north of Scotland endures arctic conditions in winter—which is a pity, considering the picnics this writer has enjoyed on a New Year’s Day, and the times he has taken his siesta in comfort in the sun on a Highland hill in December and January!

It is generally accepted then that the Highlands as a whole have a human history of but a few thousand years as against tens of thousands in southern England, and it is possible that such areas as West Sutherland and the north-west corner of Ross-shire did not know man until two or three thousand years ago. When man first came to the Highlands the sea was 50 feet higher than it is at present. His kitchen-middens appear near the 50-foot raised beaches in various places such as Colonsay, Mull, Islay and Oban. He was a hunter and fisher and knew no arts of husbandry. One wonders what large effects early man can have had, because a small population of hunters taking life only for its own subsistence, and not for any export, would hardly bring to extinction many of the animals we know were present at that time. It is probable that natural causes were much more important in changing the natural history of the Highlands in those days. A few degrees’ change of temperature for a period of years, for example, whether up or down, would work very great changes in the tree line and the specific constitution of the forests. The mountain tops would appear from the ice or disappear under it again for considerable spells, and everywhere the vital factor of moss growth would be affected. The growth-rate of sphagnum moss under optimum conditions has, in the deduced history of the Highlands, felled forests as surely as the fires and the axes of mankind.

The biggest effect man has exerted on the history of the Highlands has been in the destruction of the ancient forest—the great Wood of Caledon. This has happened within historic time, partly between A.D. 800 and 1100 and then from the 15th and 16th centuries till the end of the 18th. Even our own day cannot be exempt from this vast tale of almost wanton destruction, for the calls of the two German wars have been ruthless (Plate 7a). Much of this priceless remnant in Strath Spey and Rothiemurchus has been felled for ammunition boxes and the old pines of Locheil Old Forest went up in smoke during Commando training. These facts should never be forgotten as one of the consequences of war, and if nature reserves ever become a reality in the Scottish Highlands (as something distinct from National Parks, which are lungs for the people and playgrounds), the authorities should go to a great deal of trouble to bring about regeneration of the true Scots pine which is a tree different in many ways from the sombre article commonly grown in plantations as Scots. The true Scots pine (Plate 17) of the old forest is a very beautiful tree: its bottlegreen is distinctive, and so is the redness of its boughs; the needles are very short and the shape of the mature tree is often much more like that of an unhindered hardwood than the commonly accepted notion of a pine. A long clean stem is not necessarily typical. The true Scots pine is not easy to grow now, and when it is suggested that the authorities should be prepared to go to a lot of trouble to bring about its regeneration, it is because care and patience will be needed in addition to willingness. Regeneration, however, is a subject for a later chapter; we are now woefully concerned with destruction and its effects.

The old forest consisted of oak at the lower levels, with alders along the rivers and in soft places, and pines and birches elsewhere. Pines clothed the drier portions and birch the higher and the damper faces of the western hills. The true Scots pine is a relic in the ecological sense, and where fire or the hand of man swept away an expanse of the old pine it was birch which within a year or two provided the new growth. An excellent example of this opportunism of the birch is to be seen at Rhidorroch, above Ullapool, Ross-shire, where the early felling line is clearly marked, pines above and birch below, the opposite arrangement to what would be found in nature. The oak forest has nearly all gone, Argyll and southern Inverness-shire being the main parts where it is to be seen to-day in any quantity. Scarcely anywhere is it being taken care of, or regeneration active.

Nairn (1890) says that the great Caledonian Forest extended “from Glen Lyon and Rannoch to Strathspey and Strathglass and from Glencoe eastwards to the Braes of Mar.” The imagination of a naturalist can conjure up a picture of what the great forest was like: the present writer is inclined to look upon it as his idea of heaven and to feel a little rueful that he was born too late to “go native” in its recesses. But probably it was not so idyllic; the brown bears would have been little trouble, nor would the wild boar, and perhaps the wolf would not have given too many sleepless nights, but there would almost certainly have been more mosquitoes than at present, and malaria would have been a constant menace to our enjoyment of this primitive sylvan environment and its rich wild life.

The main trouble between A.D. 800 and 1100 was the Vikings, whether Danes or Norwegians. They were a destructive and parasitical folk, however colourful and well organized the civilization of the North may have been. Sometimes they set light to the forest to burn out the miserable natives who had taken refuge within it, and sometimes these same poor folk set light to strips of forest to act as a protection and screen from the Vikings. It would all depend on the airt of the wind, but the forest suffered anyway. The tradition of the burning by “Danes “ or “Norwegians” still exists in legends which may be heard in the North-West Highlands to-day. I know of several places said to be concerned with the burning in the forest of a Viking princess and the site of her grave has been pointed out to me in two places fifty miles apart. The West Highlands were also a source of boat-building timber for the Norsemen in Orkney and Iceland (Brögger, 1929).

The wanton burning of the western portions of the forest would doubtless be eased after Somerled’s Lordship of the Isles became established in the 11th century. This period was the most cultured and well ordered the West Highlands were to know for hundreds of years. Even as late as 1549, Dean Monro speaks of the wooded character of Isle Ewe and Gruinard Island in Ross-shire, affording good hiding for thieves and desperate men.

The woods of the Central Highlands were destroyed from the south-east. Gentlemen like the Wolf of Badenoch (floruit 1380) who was a brother of King Robert of Scotland, wandered through the country with large armed bands bent on plunder. Once more it was found that setting light to the forest was an easy way of smoking out or finishing off anyone who resisted. Local clan feuds must also have been a constant cause of forest fires of greater or lesser extent. The forests about Inveraray were destroyed by Bruce in an expedition against Cummin.

All these causes of destruction considered, we are still brought back to what I believe is a fundamental factor in the relation of man to the wild life around him, whether animal or vegetable. Man does not seem to extirpate a feature of his environment as long as that natural resource is concerned only with man’s everyday life: but as soon as he looks upon it as having some value for export—that he can live by selling it to some distant populations—there is real danger. The forests of the Highlands were discovered (this word was used at the period) by the Lowland Scots and the English at the beginning of the 16th century. Queen Elizabeth of England prohibited iron smelting in Sussex in 1556, and in the Furness district of Lancashire in 1563, because of the devastation caused to English woodlands. The smelters had to move farther north. The Scottish Parliament saw to what this would lead and passed an Act prohibiting anyone “to tak upoun hand to woork and mak ony issue with wod or tymmer under payne of confiscatioun of the haill yrne.” We can see exactly how this Act would work from the operations of black markets in Britain during the second German war. The game was so profitable that an occasional heavy fine was accepted as a normal tax on trade.

At this time also the woods were being destroyed actively for another reason—or perhaps two reasons. Thieves and rebels hid in the woods and wolves bred therein. It seems that infestation of the forests with these two forms of predatory fauna was so bad that it could be endured no longer. Menteith in The Forester’s Guide quotes an order by General Monk, dated 1654, to cut down woods round Aberfoyle as they were “great shelters to the rebels and mossers.” Ritchie, in giving an account of the extinction of the wolf in Scotland, mentions local tradition and definite record of woods being destroyed in the districts of Rannoch, Atholl, Lochaber and Loch Awe for this very purpose.

The suppression of the first Jacobite rebellion of 1715 gave an impetus to destruction. English business enterprises such as the York Buildings Company purchased forfeited estates and quite unashamedly set out to exploit them. Whatever was worth taking was taken, and the timber was one of the first things to go. But for the obstructive tactics of the Highlanders themselves it is probable that every vestige of pine forest would have gone at this time. The York Buildings Company went bankrupt, but not soon enough from the naturalist’s point of view. Even after this period between the rebellions, the higher standard of living which was more or less imposed on Highland proprietors by their taking up the English way of life, caused them to sell large areas of forest for smelting purposes. The prices paid for the trees were often ridiculously small. Ritchie says:

“The destruction wrought by these later and larger furnaces was irreplaceable. In 1728, 60,000 trees were purchased for £7,000 from the Strathspey forest of Sir James Grant…About 1786 the Duke of Gordon sold his Glenmore Forest to an English company for £10,000; and the Rothiemurchus Forest for many years yielded large returns to its proprietor, the profit being sometimes about £20,000 in one year.”

The last of the felling and smelting with charcoal seems to have been as late as 1813. The brothers Stuart, 1848, mention twelve miles of pine, oak and birch being burned in Strathfarrar to improve the sheep pasture.

The effects of the normal spread of arable cultivation with a rising population may be taken for granted, but this does not by any means round off the story of the changed face of the Highlands through the destruction of the pine and oak forests. The passing of the forests heralded another biological phenomenon of great significance for the natural history of the Highlands, and which was also brought about by man’s agency. This was the coming of the sheep. The old husbandry of the Highlands and Islands was a cattle husbandry, a well-ordered sequence of rearing in the islands and of feeding in the mainland glens and on the hillsides before the strong store beasts were driven away south to the great fairs such as Falkirk Tryst. The Highlands were a country unto themselves into which Lowlanders ventured with some wariness. The collapse of the second Jacobite rising in 1746 allowed flockmasters from the Southern Uplands to think about the exploitation of the new expanses of grazing in the North. “The Coming of the Sheep,” as this colonization of the Highlands was called, is one of the epic events of Scottish history, though it is one not commonly referred to in history books.

The end of the rising of 1745 meant an end of internecine warfare among the clans, which in turn favoured the survival of more men. The human population of the Highlands rose considerably during the second half of the 18th century, a fact we know as a result of Dr. Alexander Webster’s industrious work in effecting a census in 1755. Yet the extension of sheep-farming on the ranching system of the Southern Uplands meant a way of life in which fewer men were needed; also, the new sheep farms needed the crofting ground of the glens for winter pasture. The Highland gentry at this time varied greatly in achievement of the aristocratic ideal. Some had little thought at all for the clansfolk in the glens now that they had no further military significance, and others, finding themselves drawn into English metropolitan life, needed ready money—and a lot of it. Whether they were sorry or not to see their forests go in the space of a few years, it is unlikely that they considered with anything but satisfaction the new and profitable use to which it was now possible to put their land. The flockmasters offered high rents which the new clean ground amply repaid.

The old sheep of the West Highlands and Islands were akin to the present Shetland breed, but apparently they were never very numerous. The sheep now coming north with the Border men were Blackfaces which had been bred there since the 16th-17th centuries. The Scottish Blackface (Plate 8), now so common on Highland hills and through the Islands, should not be thought of as indigenous. Its origin is in the Southern Uplands; before that the north of England; before that the Pyrenees (where a prototype may be seen to-day) and possibly before that somewhere in Central Asia. The sheep were crossing the Highland Line into Dumbartonshire before 1760; by 1790 the occupation was complete in most of Argyll and in Perthshire and the sheep were plentiful in Mull and Inverness-shire. The first sheep farm in Ross-shire was settled in 1782 where it is said the occupant was a lonely man for some years. He was joined by many others at the turn of the century. Cheviot sheep-farming in Sutherland (Plate 3a) and Caithness was begun largely through the energy of Sir John Sinclair of Ulbster in the early years of the 19th century. Extensions continued until 1850. Profits were large for both landlord and farmer, but the poor folk found themselves in a bad way. Their husbandry was relatively intensive, the ground being made into lazy-beds (feannagan) wherever slope and exposure made cultivation possible. These well-drained ridges, all turned by hand, grew good crops of barley and oats, and later of potatoes, which crop in itself allowed a greater density of population by its great increase of food supply. Fencing was relatively unimportant for there were so few sheep and the cattle were tended and kept out of the arable ground by the old men and children. The arrival of a heavy stocking of sheep on the hill made the position of these people untenable. They were cleared by the landlords and many thousands chose to emigrate. The folk who remained were pushed to the coasts where their crofting townships are to-day.

Sometimes these coastal townships were places of such extreme exposure and poverty of soil that after a hundred years of hand-to-mouth existence the crofts have gone empty. The sight of such a derelict and decrepit township (Plate VIIIb) is a most saddening and disturbing thing. It does not present the ruin of a civilization by sack or natural catastrophe, but the quiet failure of simple folk to obtain subsistence from their environment. In other places, the shift to the coast has proved almost a salvation, for the people have found a mild, sheltered and early climate, and natural resources in fish and seaweed which have enabled them to live much better than they could have in the inland glens. These coastal crofting communities vary greatly in habits and thus in their influence on local natural history. Some have a shore from which they can fish, others have a rocky shore or no aptitude for fishing and they turn their energies inland to breeding sheep. It is an unfortunate characteristic of many of the crofting townships, whether fishing or pastoral, that the small quantity of arable land is being neglected, and the vegetational complex of rushes and sedge is creeping in to both unoccupied and occupied crofts.

The coming of the sheep finished the process of changing the face of the old Highlands of the time of the forests. Large areas of birch scrub were burned. Where the birch trees were larger they were cut that their bark might be exported for tanning material for sails and rope. I know of one sheep farm in the North-West Highlands (now back to a famous deer forest) where the shepherds were paid in part with the value of birch bark which they themselves had to cut and peel while they were in the hill. The flockmaster’s firestick was a destroyer of ground cover over hundreds of thousands of acres, for even where the pine trees had been cut a new growth of birch was taking place which might yet have made a less bare Highlands than we know to-day. Every spring some patch of heather or purple moor grass (sometimes known as flying bent grass or Molinia coerulea) would be burnt and seedling trees would suffer. Much birch was cleared in the 19th century by the bobbin-makers working for the cotton mills of the Lowlands and Lancashire. The pirn mill at Salen, Loch Sunart, was the principal reason for the establishment of that settlement.

The sheep themselves, as we shall see in the next chapter, are the destroyers of a habitat in which scrub trees such as birch, willow and rowan are a part (Plate 23a). Regeneration in places where they reach beyond a very low density is impossible, and even the many flowers of the countryside disappear beneath their ever-questing and selective muzzles.

Even the sheep have not been quite the last straw in man’s despoliation of the Highland forests, because his railways have happened to run through some of the last expanses. The old Highland Line (now L.M.S.) running through the Grampians and Strath Spey has been the cause of burning a good many acres of the ancient pine woods. This incidental destruction is hard to bear in a time when we have come to treasure the few remnants of primitive sylvan beauty. But I would say this: we still do not take enough care. Every year or two there are fires in Strath Spey which take away more and more of these beautiful trees. The present Laird of Rothiemurchus, discussing the question of national parks with me, said that 3,000 acres of wood had been burnt in his lifetime. If some of the last remnants of the forests are to become the property of the nation, each one of us must be conscious of his personal responsibility in preserving them.

The destruction of the forests meant the end of a habitat for much other wild life which thereupon became extinct, was compelled to change its habits or was reduced to a very low population which would be in danger of extinction from other and often obscure causes. It has come to be generally understood nowadays, that the animal population of a region is not static. There is constant fluctuation in progress. But the purpose of this chapter is not to dwell on this natural rising and falling of numbers, so much as to mention the more startling events such as actual extinctions, retrogressions, resurgences, and introductions of new species within the area of the Highlands. The list of such events and movements is a considerable one.

The causes of extinction may be various but in the main, as has been said, the active disturbing factor is man, and as one looks through the list, the losses of the last 200 years are large in proportion to those of the previous 10,000 years.

Changing climate is an immensely important mover of species and when climate changes in a relatively small island such as Britain, extermination is often the fate of land mammals which cannot readily adapt themselves. Again, if man is present and the animal of fair size, he may speed the influence of climate.

The lemming and the northern rat-vole may be taken as examples of changing climate being the dominant factor in exterminations in the Highlands and in the country as a whole. They must have disappeared with the advent of the warmer Atlantic climate and the extension of forest growth. Vestigial arctic climates such as that of the 4,000-foot plateaux of the Cairngorms have been insufficient to maintain the lemming, which occurs in similar country in Norway.

The giant Irish elk (Megaceros hibernicus) disappeared in prehistoric days also, probably before the advent of man. Climate was an active factor, but the organism itself was heading for disaster. The biological principle of heterogonic growth was at work in extravagant fashion. The evolution of antler form and weight had no particular relation to function, but was a concomitant of increasing body size and followed a different growth rate. The great annual drain on the constitution of the Irish elk, of growing 80–90 pounds of bone tissue, was too much in an age which was changing from that of the rich pasturage of the Pleistocene. Whereas the red deer grew smaller in every way, and thus adapted itself, the giant deer apparently died in all its glory. It is thought that the northern lynx persisted in the Northern Highlands until man came, but soon afterwards it became extinct. The species was probably in decline with the rise of the warm Atlantic climate, but was given the final push into extinction by Neolithic man. Bones of the northern lynx were found near the hearths in the limestone cave of Allt na Uamh near Inchnadamph, Sutherland. Ritchie says this is the one appearance of the species in Scottish history.

The brown bear was probably never a numerous species in the Highlands. The assumption of its disappearance in the 9th–10th centuries means that man must have been responsible, for climatic change had long ceased in its more violent forms and the destruction of the forests had scarcely begun.

The reindeer inhabited the Northern Highlands well into the historic period. The rise of the Atlantic climate may have reduced its original numbers, but had it not been for man’s influence it would probably have survived as the woodland type of the species. The destruction of the forests must have greatly restricted its range and finally its extermination must have been due to direct hunting. The Orkneyinga Saga mentions the hunting of the reindeer by Rognvald and Harald of Orkney, and the date assigned to the event is about the middle of the 12th century, but the species was extant later than this.

The elk (or moose) persisted in the north until rather later than the period of the brochs, defensive stone towers which were built about the 10th century, and given up when the Norse raids developed into conquest, i.e. about A.D. 1000–1100. Man, by direct hunting and the indirect means of destruction of forest which had then begun, was the cause of its disappearance by about A.D. 1300. Legends of a large dark species of deer are common in the Highlands.

The beaver was found in the Highlands until the 15th–16th centuries, Hector Boece mentioning its existence about Loch Ness, and its being hunted for its skin.

We may consider next a group of three diverse creatures which are extinct as wild animals of the type they were in the 13th, 14th and 15th centuries, at which time they disappeared; but which still lived on in domesticated forms or crosses with other domesticated stocks. The wild boar would be found wherever there were oak woods and would impoverish the flora therein by its constant delving. Its domesticated descendants persisted in the West Highlands and Islands until the middle of the 19th century, at which time swine ceased to be kept as a general practice. The conversion of the people to an extreme type of Presbyterianism engendered a Judaic attitude to the pig, and numbers fell away rapidly after the 19th century conversions. Any fresh pigs to come in were of the improved type from England, where the quick-fattening Chinese pig was altering the form of the old “razorbacks.” The great wild ox or Urus, surely the most magnificent member of the northern fauna, also disappeared through hunting and the clearing of the forest, but its blood may be presumed still to run in the veins of the West Highland breed of cattle (Plate 9). The Highlands also had their wild ponies which were truly wild and not feral. Cossar Ewart has pointed out that these ponies lacked callosities on the hind legs. Hector Boece mentions the ponies in the same passage as that in which he records the beavers of Loch Ness. The Scottish wild horse received crosses of Norse blood, and later of Arab, so that the Highland pony of to-day (Plate IX) has at least some claims to represent the indigenous stock.

The white cattle with black hooves, muzzles, eyes and ears remain to us to-day in a few herds in large parks. They are rather poor creatures, having been greatly inbred through lack of numbers. None of them is in the Highlands. Cattle of this colouring arise from time to time, and I believe that it would not be difficult to build up a herd of strong-coated white cattle with black points from the existing cattle stocks of the Highlands and Islands. Similarly with the ponies, we could find a few Celtic ponies (Equus caballus celticus) cropping up as segregates from the Hebridean herds, and build up a stud of them. These two species would be an asset to a future wild-life reserve in the Highlands.

The story of the wolf in the Highlands is important because this animal was responsible for a good deal of the later history of the destruction of the forests. Clearance of the forest by burning was doubtless the easiest way of restricting the wolf’s range. The last wolf of Scotland was killed by one Macqueen on the lands of Mackintosh of Mackintosh, Inverness-shire, in 1743. Passage through the Northern and Central Highlands in the 16th century was hazardous enough for hospices or “spittals” to be set up where the benighted traveller could rest in safety. Wolves were plentiful and hungry enough to cause people in the Highland areas to bury their dead on islands offshore or in lochs. Examples of such islands for which this tradition exists are Handa, Sutherland; Tanera, N.W. Ross; and Inishail, Loch Awe, Argyll. A detailed account of the wolf in Scotland may be found in Harting’s British Animals Extinct within Historic Times (1880).

Only one mammal has become extinct in the Highlands in the 20th century, though several have come near extinction in our day and have then rallied. The polecat has gone from Scotland though it still exists in moderate numbers in mid-Wales. The intensity of game preservation and the skill of Scottish gamekeepers in trapping are doubtless responsible. Even as I write, Highland fox-hunting organizations have expressed “satisfaction” at kills not only of foxes but badgers, otters, weasels and stoats. These same men will soon be yapping their dissatisfaction at plagues of voles and rabbits and calling on that universal Aunt Sally of Scotland, the Department of Agriculture, “to do something.”

From the animals and dates mentioned so far in this chapter, we gather that several mammals disappeared between the years A.D. 1000 and A.D. 1743. Birds were more fortunate, but their turn was to come with the improvement and lightening of the fowling-piece, the rise of game preservation and the spread of land reclamation. Almost as the last wolf howled in the Highlands, extermination of certain birds began. The first were the crane and the bittern which went in the 18th century, partly by direct hunting for feathers and food, but mainly through draining the marshes for land reclamation. It may be said, incidentally, that this characteristic 18th-century movement for draining was also responsible for the extirpation of malaria from Scotland.

The absolute extinction of the great auk is a story so well known that there is no need to recount more of it than the gradual diminution on St. Kilda as a breeding species during the 17th and 18th centuries. By 1840, when the last great auk was caught and killed on St. Kilda, the captors were unaware of its identity, and the bird was actually killed because of their fear of it. Where there is no written word current, tradition is unsure in its action.

All the other extinctions are of the raptorial tribe. The decline and disappearance of the osprey in the 19th and 20th centuries is recorded elsewhere in this book. The least-known extinction is of the goshawk, which was still present as a breeding species in the 19th century, having its eyries in great pine trees of the remnant of the Caledonian Forest. The kite was finished but a few years afterwards. The Harvie-Brown Vertebrate Fauna Series are good sources of information on the last haunts of all these raptors. The white-tailed or sea eagle has been the last to go. Shetland has the last breeding record in the present century. The West Highland and Hebridean coasts, being nearer to extensive sheep-farming interests, lost their sea eagles rather earlier. By 1879 they had gone from Mull, Jura and Eigg. The species finally ceased to breed in Skye, the Shiant Isles and the north-west mainland about 1890. It is all a dismal story; and it is a matter for doubt whether, should these species try again to colonize this country, they would be allowed to breed in security. The vested interests of game preservation (by no means dead in a Socialist Britain), of a decrepit hill sheep-farming industry in the West Highlands and Islands, the pressure of egg collectors and irresponsible gunners, are heavy odds.

A local extinction is worth noting, namely, the ptarmigan in the Outer Isles. Their last haunt was on Clisham, Harris, the highest hill in the Hebrides. Seton Gordon in his recent book A Highland Year (1944) says that rabbits became very numerous on the drier slopes of the hill, and that ferrets were turned down to cope with them. He says the ferrets also preyed upon the ptarmigan and are in his opinion responsible for their extermination. This animal achieved what the related pine marten failed to do in its day in the Forest of Harris.

There is one invertebrate extinction to be recorded, the oyster. The northern oyster was common in many sheltered shallow bays up and down the West Highlands, but it has now gone, probably due to gross overfishing, with possibly a run of low-temperature summers which would hinder breeding. Experiments have been made in reintroduction, but the southern oyster from French waters has been used, and as might have been expected, has not been successful. The temperature of the water does not reach and remain at 60° F. for a long enough time.

The status of our two British seals, the Atlantic grey seal (Halichoerus gryphus) and the common or brown seal (Phoca vitulina), is interesting as an example of the influence of man on the species. The common seal is truly common though local: it occurs in large numbers in the Tay estuary where it is regularly hunted, but without complete success owing to the sanctuary given by the sand banks; it is common in Orkney, and the seas of Shetland hold very large numbers. The common seal is of much less frequent occurrence on the West Highland coast, though there are pockets of twenties and thirties in some of the sea lochs and among the groups of islands. The Atlantic seal is much commoner on this coast though it favours the more outlying places.

The common seal is immensely more damaging to nets than the Atlantic seal, but its habits are such that any attempts by man to lessen its numbers severely have little success. When the young are born they go to sea with the mothers immediately and the adults spend no more than a few hours at a time lying out on rocks and sand banks. The species does not flock to some traditional breeding place as does the Atlantic seal. We shall study the life history of this latter species in a later chapter; our concern with it here is in the habit of retreating to more or less remote islands to breed, and in spending some weeks out of the water. The Atlantic grey seal is at the mercy of man at such a time, for he finds gathered at these places the population of a great length of coastline, with the animals at a severe disadvantage.

The grey seals (Plate 28 and Plate XXX) were regularly hunted in the Hebrides during the autumn breeding season, without reference to age, sex or condition of the animals; for the visits to the nursery islands were governed by the state of the sea. The result was a diminution in numbers which did not become dangerous until the 19th century when the species was faced with the fact which I have mentioned and repeated elsewhere in this survey of Highland natural history—danger for the species comes when the toll taken is for export and not for the limited and constant needs of a resident human population. The skins of the Atlantic seals were being bought and resold by the Danish Consul in Stornoway. The fishery was wasteful in the extreme and quite unorganized. Then came a remarkable relief for the seals in cheap rubber boots for the fishermen, and synchronously, almost, the arrival of cheap and clean paraffin for lamps. Rubber boots were much less trouble in every way than those of seal skin, and only those who have tried the smoky flame of seal oil can fully appreciate the boon of paraffin. The seals got some respite except for the fact that the hunting had become a traditional social occasion which had to be gradually broken down. Happily, the Government made an Order prohibiting the slaughter of Atlantic grey seals during the whole of their breeding season. The species has increased and is now numerous again to an extent it cannot have known for centuries. It is spreading to islands and mainland coasts from which it had long disappeared, and is now a feature of the natural history of the West which anyone can hope to enjoy, and have the opportunity to see and watch in the course of a short holiday. This story of an animal’s survival is an example of the importance of human ecology in relation to that of the animal. No British mammal could be more easily exterminated, because of the nature of its breeding habits. Its future is entirely in man’s hands.