Mammal Rev. 1986, Volume 16, No. 2,53-63. Printed in Great Britain

Opportunities for reintroducing British mammals D. W. Yalden Department of Zoology, University of Manchester, Manchester MI3 9PL

ABSTRACT There is good evidence that the three rarer British predatory mammals, the Polecat, Pine Marten and Wild Cat, owe their present restricted distribution to intense human persecution. Since this persecution has now diminished considerably, it would be feas- ible to attempt to reintroduce them to parts of Britain where they were exterminated last century. More important, however, would be attempts to reintroduce mammals which became totally extinct in historic times, including Aurochs, Boar, Brown Bear, Beaver and Wolf. The last of these survived the longest, and is a prime candidate for consideration. There are good ecological reasons for attempting to reintroduce it to Rhum, where the large herd of Red Deer has to be culled by one sixth each year in an attempt to reduce overgrazing and starvation. Evidence of studies in North America suggests that Wolf predation would be a far more efficient way of controlling the Red Deer; and it would be more in keeping with the management objectives of a National Nature Reserve. Similarly an attempt should be made to use genetically ‘reconstituted’ Tarpan and Aurochs to diversify the grazing, rather than domestic ponies and cattle.

INTRODUCTION The Working Group on Introductions (Green, 1979) gave a cautious approval to the concept of reintroductions; they noted, however, several provisoes. Foremost of these were that we should have some understanding of why extinction occurred, believe that those causes have ameliorated, and that suitable habitat is available. They also argued that appropriate genetic stock should be used, and that the donor populations should not suffer a serious drain of their recruits. More recently, the Nature Conservancy Council (1984, p. 96) has introduced the concept of ‘Creative Conservation’. With this sympathetic background, what opportunities exist for reintroducing British (or formerly British) mammals?

Conditions for reintroduction Of the factors responsible for exterminating or severely restricting the range of British mammals, direct human persecution was undoubtedly the most acute. This per- secution came in part, and initially, from the general rural population, latterly and most severely from the gamekeeping population. Moore (1957) drew attention to the negative relationship between the distribution of gamekeepers and the Buzzard Buteo buteo; the same relationship applies to other predators, both avian and mammalian. The Red Kite Milvus milvus like the Polecat Mustela putorius was formerly common but survived into the twentieth century only in Wales; the Golden Eagle Aquila chrysaetos and Wild Cat Felis sylvestris survived only in Scotland; the Pine Marten Murtes martes, like the Buzzard, held out in various of the northern and western mountainous areas (Langley & Yalden, 1977). Human persecution is certainly a factor

54 D. W . Yalden

which has ameliorated. The gamekeeping population reached a peak in the 191 1 cen- sus (23 000), and has now declined to about 5000 (Potts, 1980). The rural population of England and Wales reached a maximum of around 8.4 million in the 1841 census, and has declined ever since; at the 1911 census it was down to 5.6 million and is now around 3 million people (Coppock, 1976, p. 296). Thus the potential persecutors of rural mammals are now far fewer. The repeal of the 1566 Act for the ‘Preservation of Grayne’ in 1863 also removed some of the persecution pressure.

It is less certain that other pressures are reduced. Deforestation reached its maxi- mum in the eighteenth century, when the Roe Deer Capreolus capreolus became extinct in England, and the Red Squirrel Sciurus vulgaris was practically exterminated as well (Yalden, 1982). Subsequently the extent of woodland has increased somewhat, but Britain still has only about 8% woodland cover, and is among the least wooded countries of Europe. Moreover, much of this new woodland is of exotic conifers, not the deciduous woodland to which our native mammals are presumably adapted. Coppice woodland, in particular, declined from 1417 km2 in 1947 to only 296 km2 in 1965 (Edlin, 1970). Hedgerows have also declined. Drainage of our wetlands, largely completed in the nineteenth century, has not, for mammals, been compensated by the new habitats that reservoirs offer. However many bird species have benefited, reservoir banks do not provide the cover, nor the opportunities for burrowing, that natural waterways allow to mammals.

Of other actual or potential threats to our mammalian fauna, we can at least hope that organochlorine pesticides have come under control. Since the Peregrine Falcon Falco peregrinus and Sparrowhawk Accipiter nisus have recovered so well since their nadir in 1962-1963, it is reasonable to hope that the Otter Lutra lutra, which was also badly affected by pesticides (Jefferies & Chanin, 1978), will show signs of recovery, with or without further help (Jefferies et al., 1986). The improving climate of opinion in Britain, reflected in increasing membership of the R.S.P.B. and the R.S.N.C., in the N.C.C. report already mentioned (N.C.C., 1984) and indeed epitomized by this conference, also augurs well for prospective reintroductions.

Opportunies for spreading existing rarer mammals In view of comments in the previous paragraphs, it must be accepted that opportuni- ties for reintroducing some of our rarer mammals to areas where they have become extinct are negligible. This is particularly true for several woodland species. The Dormouse, Muscardinus avellanarius, for example, is now both more restricted in its range and rarer in those places where it survives than at the turn of the century (Hurrell & McIntosh, 1984). In particular, the species was not reported in the recent survey from seven counties (Warwickshire, Staffordshire, Cheshire, Yorkshire, Derbyshire, Lincolnshire, Norfolk) where formerly it occurred. It may, in fact, still survive undetected in small numbers or in odd localities, but it is certainly not common in those counties now. The prospects for reintroducing it, however, seem negligible, in view of the continuing decline of hedgerows, coppice woodland and, in particular, of the hazel Corylus avellana. Conservation effort would, in any case, be better applied to improving or maintaining habitat in areas where it does still occur. The Yellow-necked Mouse Apodemus jlavicollis, with a similar distribution, and a similar history (Yalden, 1984), is another case where reintroduction would not be use- ful. One of Britain’s rarest mammals, the bat Myotis bechsteini, belongs with these two. It too is apparently a deciduous woodland specialist, and was much more common in

Reintroducing British mammals 55

Neolithic times when such woodland was widespread (Clark, 1963). It would be non- sense to advocate the reintroduction of so mobile an animal, and one so difficult to study or breed, of course, but in any case its habitat is now scarce, and seems likely to remain so.

Another mammal now much restricted in its distribution, particularly in England and Wales, is the Red Squirrel. Again, I see little prospect for successful reintroduc- tion; the negative correlation between the range of the introduced Grey Squirrel Sciurus carolinensis and the native species is too convincing (Lloyd, 1983; Reynolds, 1985). While the nature of the competition between these two remains difficult to ascertain (MacKinnon, 1978), its ecological reality seems undoubted. Since the Grey Squirrel is certainly here to stay I cannot see any long-term prospect for the Red Squirrel in southern England, except on islands (e.g. Brownsea, Isle of Wight) which the Grey Squirrel cannot reach (but see Bertram & Moltu, 1986). In northern Britain, the spread of the Grey Squirrel has been much slower, and it is possible that the Red Squirrel may be able to outcompete it there.

This leaves three rarer mammals which do merit serious consideration; the three carnivores which were mentioned earlier. Of these, the Polecat represents the best prospect. All three species are now increasing their ranges, implying that the formerly adverse factor (persecution) has declined. The Polecat was the commonest of the three, survived longest in south-east England, and became the most restricted in range. Howes (1980) discusses in detail the evidence for the decline of the Polecat in Yorkshire, and the factors responsible. While habitat change, especially drainage of the fens, was one factor, the evidence of long-term persecution that he documents sup- ports Langley & Yalden’s (1977) arguments; his evidence does suggest, however, that the main population decline was a century earlier than they argued, and corresponded especially with the development of the sport of pheasant shooting. Davis & Newton (1981) have pointed out that Red Kites in Wales have a poorer reproductive rate than those elsewhere in Europe, and they suggest that this reflects the poorer productivity of the hill land where Kites live. The same arguments might well apply to the Polecat in Wales, and offer another good argument for attempting to hasten its spread. The fact that its congener, the American Mink Mustela ‘uison, has spread so successfully is another argument in favour. The two species are of similar size, with similar prey and habitat requirements and the spread of the Mink implies that the niche is (or has been) vacant. The possible areas for such a trial introduction include Sutherland, Speyside, Cornwall, the Lake District and perhaps the Weald. Polecats lingered in Cumberland and Sutherland later than in most counties (Langley & Yalden, 1977).

The Pine Marten presents a slightly more difficult prospect. Given that it is sup- posed to have survived in Wales and Cumbria as well as in Scotland, it is puzzling that it has not, apparently, increased in those areas (as it certainly has done in Scotland). Velander (1983), reviewing the current status and distribution, draws attention to the fact that deliberate persecution still accounts for most of the known mortality, and many of the distribution records. She also draws attention to the species’ preference for woodland with good ground cover, and O’Sullivan (1983) makes the same point for Irish Pine Martens. She reports that reintroduction of this species, to southern Scotland, has already been attempted, and seems to be successful (Velander, 1983). Wooded areas of England, especially the Breckland, Quantocks, and the Weald, might therefore be worthy of consideration for further attempts.

Prospects for reintroducing the Wild Cat outside of its current range seem to be the most gloomy of these three. It declined earlier than the other two, being rare or extinct

56 D . W. Yalden

in most of England by 1800. There is also a strong risk of interbreeding with feral, or indeed domestic, cats if an attempt were made to reintroduce it to more populous parts of Britain, so that the survival of a population of true Wild Cats would be less certain. On the other hand, the rate of spread of the species in Scotland seems to be greater than for either Polecat or Pine Marten, providing hope that such a venture would be less necessary. The animal requires a good supply of medium-sized mammal and bird prey to sustain it, and in southern Britain that implies Rabbits in particular. Areas such as the Breckland, parts of Wales, or Devon and Cornwall seem worth consider- ation. Conservation interests might express concern that species like the Stone Curlew Burhinus oedicnemus could suffer, but it is difficult to believe that losses from the

’present suite of predators (Fox, Stoat, Weasel, Feral Cat) which such species must withstand would be seriously augmented by another predator. Possibly the predator populations are sufficiently depressed by gamekeeping activities on surrounding estates that another predator would have an appreciable effect, and this point merits further research. Tapper, Green & Rands (1982) demonstrate that even current levels of gamekeeping activity are capable of controlling predator numbers on a local basis, so that rarer, reintroduced, species would be unlikely to get ‘out of control’.

Opportunities for reintroducing extinct mammals Having discussed some possibilities for spreading the distribution of rarer mammals within Britain (and having deliberately omitted the Otter, Lutra lutra, discussed by Jefferies et al., 1986), it has to be said that such possibilities are not really of major sig- nificance. None of the current British mammals which could be assisted in this way are seriously endangered, most are spreading naturally, and there are far better subjects for our concern. These are the suite of large mammals which are extinct in Britain. Several of them are rare and declining in Europe, and a couple of them are totally extinct, at least as wild animals. It is worth noting that our avifauna, of some 210 breeding species, is still largely complete. With the assisted return of the Sea Eagle Haliaeetus albicilla (Love, 1983) only seven or eight (4%) former breeders are now missing. Four or five of these are fenland species, whose habitat has probably gone (Grus grus, Ciconia ciconia, Platalea leucorodia, Pelecanus crispus, ?Phalacrocorax pygmaeus), leaving only the Eagle Owl Bubo bubo, Hazel Hen Tetrastes bonasia and Great Bustard Otis tarda as possible subjects for discussion. By contrast, of our 42 recent native land mammals, seventeen (40%) are extinct (using the listing in Yalden, 1982, Table 3). Of these, eight were northern forms which lived here in the tundra conditions of Late Glacial times, and whose extinction was surely the result of climatic amelioration and subsequent habitat change (two lemmings Lemmus lemmus and Dicrostonyx torquatus, two voles Microtus oeconomus and M . gregalis, the Reindeer Rangifer tarandus, Giant Deer Megaloceros giganteus, Arctic Fox Alopex lagopus and Pika Ochotonapusilla). On the other hand, the extinction of five species seems certainly due to man, by direct persecution, over-exploitation and habitat change; in order, approximately, of date of extinction these are Aurochs Bos primigenius, Brown Bear Ursus arctos, Beaver Castorjiber, Boar Sus scrofa and Wolf Canis lupus. The other four species are too poorly known as British mammals to be sure when they became extinct or through what cause; these are Tarpan Equus ferus, Moose Alces alces, Glutton Gulo gulo and Lynx Felis lynx. Given the enormous extent of forest clearance in Britain, extinction of the Lynx is likely to have been due to Man; Jenkinson (1983, 1984) has recently documented its survival into late Mesolithic times. The Moose could have

Reintroducing British mammals 57

been similarly affected, while both it and the Tarpan were probably hunted exten- sively (as the Moose certainly was at the Mesolithic site of Star Carr, see Fraser & King, 1954).

What are the prospects for reintroducing these species? Several of them are rare and declining in Europe, notably the Wolf and Bear. Two are extinct as wild mammals (Tarpan, Aurochs) but their genes are likely to survive in their domesticated descen- dants, and both have been ‘reconstituted’ in German zoos. Several have been very successfully reintroduced to parts of their European range, and are spreading (Boar, Beaver, Lynx). Smit & Wijngarden (1981) show seven reintroductions of Lynx and 19 of Beaver. So far, attempts to do so in Britain have been at best half-hearted or clandestine, and certainly not promoted officially. If the N.C.C. is really interested in ‘Creative Conservation’, there is an enormous opportunity here to achieve a great deal. I fear, at present, that there is instead a great deal of official cowardice. For there is one species in this list where powerful ecological arguments already exist for its reintroduction, and where the site for that reintroduction is already obvious. The species is the Wolf, the site Rhum, and the arguments were presented by Lowe (1969), though he did not advance them. While Nevard & Penfold (1978) did make such proposals (and my thinking owes much to their paper), their arguments were based on conservationist and economic grounds rather than ecological considerations.

The Wolf survived latest of the species listed, and that alone suggests it as a prime candidate for reintroduction. The fact that it is increasingly rare throughout its European range is another strong argument. However, the fact that Rhum is a National Nature Reserve, yet has a large Red Deer (Cervus eluphus) population which has to be severely culled each year to control it, is the strongest argument of all. When acquired by the N.C.C., Rhum had a population of 1500 Red Deer and 1700 domestic sheep; the latter were removed. At that time, the island appeared severely overgrazed, and about 16OA of the Deer starved to death each winter (Lowe, 1969; N.C.C. 1974). The level of culling was increased to about one sixth of the population each year, that is about 250 deer; even so a further 4% of the Deer still die of starvation each year (some 60 Deer), so that the culling has not eliminated natural mortality; nor is it sufficiently precise to remove all of the weak, or potentially weak, deer.

Studies of Wolf predation on Isle Royale (Mech, 1966; Peterson, 1977) indicate that a Wolf requires around 3.6 kg of meat daily. Taking the weights of 120 kg for a stag, 90 kg for a yeld hind, and 78 kg for a lactating hind given by Mitchell, Staines & Welch (1977), the cull on Rhum represents 25 500 kg of meat, and that would sustain a popu- lation of 19 wolves. However, there were, up to 1957, also 1700 sheep on the island, and there are still 100+ Highland Cattle, 25 Highland Ponies and 200 feral Goats. Presumably, then, the island could support a rather larger herbivore population, and the surplus from a notional Deer and Sheep prey population might have supported up to 28 wolves. This is larger than the Wolf population that Mech (1966) studied, and would surely be viable. What would be its ecological effects?

Mech (1966) and Peterson (1977) observed between them, from an aircraft, 180 hunting attempts by Wolves. These Wolves were hunting Moose, and the Moose fled before the Wolves caught up with them in 65 cases. Of the 115 Moose which the Wolves actually tested, only seven (6%) were killed, and one other was wounded but escaped (Fig. 1). This implies that something like 1560 adult Moose were tested by

the Wolves each year (they killed around 95 in a year, 95 x - = 1560). Since the

population was estimated to be only 70&800 Moose, this suggests that each one was

115 7

58 D. W. Yalden

MOOSE OETECTED

12 DISCOVERED WOLVES 168

FIRST AND LEFT DID NOT DETECT WOLVES FIRST

I24 STOOD AT BAY WHEN RAN WHEN WOLVES APPROACHED

>PROACHED

53 ESCAPED BEFORE 71

WOLVES CAUGHT UP WOLVES CAUGHT UP TO

CONTINUED 48 - TO STOOD AT BAY WHEN

RUN WHEN WOLVES CAUGHT UP WOLVES CAUGHT UP m OUTRAN OR OUTLASTED

WOLVES 8

WERE ATTACKED

I-----+@ OUTRAN OR OUTLASTED

WOLVES 8

WERE ATTACKED

Fig. 1. Results of interactions between all or part of a pack of 15-16 Wolves and 180 Moose in Isle Royale National Park. Circled figures indicate those Moose actually ‘tested’ by the Wolves (Mech, 1966; Peterson, 1977). Such large ungulates are clearly difficult prey for Wolves, and most escape; one would expect Red Deer, which run faster than Moose, to be at least as difficult to catch.

tested two to three times annually. These large ungulates, in other words, are not easy prey for Wolves, and the vulnerable (sick, diseased or starving) individuals are most likely to be killed (Peterson, 1977). This indeed was what autopsies of the Moose revealed (Fig. 2). Young and very old Moose (also vulnerable) were also much more likely to be killed (Fig. 3).

Clearly Red Deer are much smaller than Moose, but they would still be a difficult prey. Predation would fall heavily on calves, but as these grow, they quickly become less vulnerable. Productivity of the Red Deer on Rhum is not high at present; in the population studied by Clutton-Brock, Guiness & Albon ( 1982), the proportion of 3-year old hinds calving had fallen from 80% to loyo, and the proportion of lactating hinds which calved next year dropped from 80% to 40%. Calf survival over winter (in the total absence of predation!) fell from 50% to 30% as the study population increased. Clearly, there is spare reproductive capacity in the Rhum deer population, and it would be well able to withstand some predation of calves.

Since the carcasses left by the Wolves would be evenly distributed through the year (at present, mortality is clumped into late winter, for natural deaths, or autumn- August to December-for culling), carrion would be available, for Ravens and Eagles, throughout the year. Since Rhum is 19 km from the mainland, there is no real risk of Wolves escaping thereto. Possibly the loss of income from the current harvest of

48

44

40

36

32

2E

aJ n E, 24 z

2c

16

12

E

4

Non

Reintroducing British mammals 59

n

2 4 6 8 I0 I2 14 16 18 20 Age (years)

Fig. 2. Incidence of jaw necrosis in a sample of 480 Moose killed by Wolves on Isle Royale (Peterson, 1977).

0 Hypothetical age structure Wolf k i l l

7

Age (years)

Fig. 3. Age-distribution of adult Moose killed by Wolves on Isle Royale, compared with the theoretical age-distribution of the population (Peterson, 1977). Nearly 58% of the population is aged under 6 years, but only 26"/,, of those killed by Wolves are as young as this.

60 D. W . Yulden

venison would be serious, but this could be balanced by increased revenue from tour- ism, as indeed Nevard & Penfold (1978) argued. In any case, it is presumably no part of the function of a National Nature Reserve to make a profit, and what is proposed would enhance its function and status as a Nature Reserve considerably.

One serious argument against this proposal is the suggestion by Dratch & Soutar (1982), using computer simulation, that Wolves might not survive reintroduction to Rhum. In twenty simulated introductions, each starting with two pairs of Wolves, the Wolf population died out five times. However, Soutar (who was responsible for the Rhum simulations) used the genetically unlikely assumption of a sex ratio in the pups biased 2 males: 1 female. Imbalance of the sex ratio was stated to be the usual cause of extinction of Wolves in these simulations. It is true that Mech (1975) documented one small Wolf population with a very male-biased sex ratio, but he was at pains to point out that this was unusual; overall, his sample of pups produced a sex ratio of 1.14 ma1e:l female. Soutar (pers. comm.) used the 2:l sex ratio because of evidence that pup survival may be biased in favour of males in high density wolf populations.

Nevard & Penfold (1978) went further than I have so far done, in arguing that an attempt should be made to recreate on Rhum the West European large mammal fauna as a tourist attraction. There is nowhere that a fully functional large mammal eco- system exists in Europe, which perhaps explains the attraction of East Africa for naturalist-tourists. My own reaction to their detailed suggestion is that the end result sounds more like a zoo or wildlife park than a functioning ecosystem, with too many non-native species involved. A more selective approach seems highly desirable. At present, there might be insufficient woodland on Rhum for either Brown Bear or Lynx to survive, and before the Lynx could be introduced, populations of smaller herbi- vores would have to be established-Roe Deer Cupreolus cupreolus and the two hares Lepus timidus and L. europueus are the obvious candidates. The hares would, in any case, be valuable prey for Golden Eagles Aquilu chrysuetos, and their presence might allay Love’s (1983) fears of the reintroduced Sea Eagle displacing the Golden Eagle.

Paradoxically the Beaver and Boar might be the most difficult species to establish on Rhum-paradoxically because both species have been widely reintroduced in Europe (Dottrens, 1965; Curry-Lindahl, 1967; Zurowski, 1979; Pinder, 1980). The Boar is a species of deciduous woodland (Genov, 1981), and there is little of that on Rhum. The Beaver, too, requires deciduous species, especially willows (Sulix sp.) and Aspen Populus tremulu, for its diet (Curry-Lindahl, 1967; Zharkov & Sokolov, 1967). Estab- lishing such food species on Rhum in the face of the current grazing levels would be difficult, and might take many years. Possibly other sites should be considered if these species are to be reintroduced. These could be other islands (Isle of Wight? Isle of Man?) if a ‘cordon sanitaire’ is felt desirable, though the damage they might do to forestry and agriculture has probably been greatly exaggerated (cf. Curry-Lindahl, 1967; Andrzejewski 81 Jezierski, 1978).

Coniferous trees are clearly not attractive to Beavers as food, and the main com- plaint seems to be that some trees have been killed by waterlogging of the soil. In both Switzerland and Poland, Beavers have been found to tolerate human disturbance well, another attribute that would be desirable in our crowded country. Wild Boars cer- tainly consume quantities of potatoes, grain, sugar beet and other crops in Poland, though an unknown proportion of this comes as supplementary winter food from hunters. If available, acorns, beech mast and other forest products are preferred. Damage can also be minimized by appropriate supplementary feeding in summer and by culling preferentially the younger animals, leaving the older Boars (especially) to

Reintroducing British mammals 61

maintain the social structure of the population (Mackin, 1970; Andrzejewski & Jezierski, 1978).

Returning to Rhum as a National Nature Reserve, and the obvious choice for many of these experiments, there is one other experiment which seems to me highly desir- able. N.C.C. have introduced both cattle and ponies, in an attempt to diversify the grazing pressure. Given that this is an N.N.R., not a Rare Breeds Survival Trust farm, it seems to me extremely unimaginative of N.C.C. to use Highland Cattle and Ponies. This was, surely, an opportunity to try instead the genetically reconstituted Aurochs and Tarpan. It might not have succeeded, and might not succeed in the face of Wolf predation either (given that ‘domesticity’ might have been bred into the strains), but surely deserves to be tried.

DISCUSSION The opportunities for reintroducing mammals to Britain are considerable, particularly in view of the wholesale extinction of all of the larger mammals. Yet there has been little serious discussion of these opportunities. In part, these extinct forms are felt to be too dangerous to man, or likely to be too harmful to agriculture. Certainly they would not be tolerated in areas of intensive agriculture, though it should not be over- looked that Boars have been widely reintroduced or encouraged to spread in France and Germany, where game hunters evidently have more influence than in Britain. Yet mammals such as these would be quite easily confined to islands such as Rhum; their chances of swimming to the mainland are very slight, and their elimination if they did so would not be difficult. The danger posed by any of them to Man has been grossly exaggerated (Mech, 1970; Zimen, 1981). Moreover, the danger posed by, for example, Lions or Tigers in the National Parks of East Africa or India would not be considered a legitimate reason for exterminating them. Indeed, as Nevard & Penfold (1978) argued, the tourist attraction posed by a community of large herbivores and its predators is enormous. As someone who paid El800 in 1980 for a family holiday on a package tour of game parks in East Africa, I speak with personal conviction. There is also a moral argument; conservationists in Britain have been foremost among those pressing for action to conserve Tigers in India, Gorillas in Ruanda, Giant Pandas in China. What have we done to conserve our own large mammal fauna? Nothing; we haven’t got one, and it is high time we had.

I do not pretend that there are no difficulties to be overcome. Suitable stock prob- ably exists already in British zoos and wildlife parks so that quarantine and veterinary problems should not arise. Purists might argue that Rhum never had the mammal fauna that is being proposed, but then the Sheep, Cattle, Wild Goats, Ponies and Brown Rats are not native there either; and if the Red Deer was native, it was extermi- nated, the present population being itself the result of a reintroduction (N.C.C., 1974). Financial constraints might be serious, but such an imaginative and positive approach to conservation should attract considerable financial support from naturalists, the tourist industry, and others. Opposition from the agricultural and forestry lobbies might also be serious, and the Press will certainly raise ignorant and prejudicial opposition (see contributions in Pimlott, 1975). Only sound dicussion and argument, perhaps insurance cover, and possibly an experimental introduction will overcome these. A more serious line of opposition might be that we do not have sufficient eco- logical knowledge to offer a fair chance of success. The only case where I would claim a reasonable knowledge of the relevant literature is the Wolf; with that, I am certain that

62 D. W. Yalden

we could achieve success. There seems to me, from a more superficial study, to be enough examples of successful reintroduction of Beaver, Boar and Lynx to be hopeful with them, too. The Brown Bear is more problematical, and may need further study. There is no way that we can study the ecology of Aurochs or Tarpan at present; that, to me, is why we should be trying to reintroduce them to the wild as well.

I therefore propose that: The N.C.C. should take a policy decision to attempt to recreate the northern Palaearctic mammal fauna on Rhum. Use of domestic herbivores to diversify grazing pressures on Rhum is difficult to justify in the context of this National Nature Reserve. Steps be taken to diversify the wild herbivore (= prey) population of Rhum. Candidates for consideration, perhaps in order, are (a) Field Vole, (b) Bank Vole, (c) Mountain Hare, (d) Brown Hare, (e) Roe Deer, (f) Boar, (g) Beaver, (h) Tarpan, (i) Aurochs. Consideration be given to reintroducing the Wolf, with a view to replacing culling with natural control by a predator. Depending on the success of introducing their prey, (a) Lynx, (b) Brown Bear, (c) Wolverine, (d) other, currently native, predators (Red Fox, Pine Marten, Polecat) should also be considered for introduction.

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