Collins New Naturalist Library. David Cabot
Чтение книги онлайн.
Читать онлайн книгу Collins New Naturalist Library - David Cabot страница 35
Mountain fauna
The fauna of Irish mountains and uplands contains very few surprises and, like the flora, is somewhat impoverished. None of the mountain ranges are high or extensive enough to provide the habitats for the true mountain species of birds such as are found in the Scottish Highlands – the ptarmigan, snow bunting and the dotterel. Even when it comes to invertebrates, especially the better investigated groups of butterflies and moths, the range of species is not one to go wild about. However, some interesting discoveries of relict arctic-alpine aquatic beetles have been made which might suggest that they survived the glacial phases of the Ice Age in some of the ice-free mountain summits. Here we will look more closely at the characteristic mammals, birds and invertebrates of mountain and upland areas.
Mammals
The largest living quadruped in Ireland is the red deer which is essentially a creature of the mountains and uplands. While there are several herds and scattered groups throughout the country, the deer in the Killarney Valley area, Co. Kerry, are probably the only ones with a claim to represent the native deer that roamed Ireland during the postglacial period. Once abundant throughout the country as a truly wild species, several herds managed to survive in the more remote areas of Erris, Co. Mayo, Connemara, Co. Galway, and in the Galty Mountains, Counties Tipperary and Limerick, until their extinction in the mid-nineteenth century (see here). Testimony of their once widespread distribution in Ireland is evidenced by the incorporation into numerous place names of the Irish word fiadh meaning ‘deer’. For example, Cluain-fhiadh, ‘the meadow of the deer’, is a parish in Co. Waterford, and Ceim-an-fhiaidh, ‘the pass of the deer’, marks the route taken by these animals when moving from valley to valley of the Lee and Ouvane areas in Co. Cork.
Two red deer hinds (F. Guinness).
The red deer living wild in the Wicklow Mountains and woods are the descendants of escapees from Lord Powerscourt’s demesne in the 1920s, although some authors date their liberation from the 1860s.38 By the mid 1930s there were approximately 50 animals living wild in the Glencree and Glenmalur areas.39 Numbers thereafter increased to about 250–300 animals during the war. Surveys in the early 1970s found only about 75 animals living in the open uplands, centred around the Mullaghcleevaun–Kippure (about 25 animals) and Glendalough–Glenmalur (about 50 animals) areas.38 A further possible 30 were living in the woodlands near Glendalough to give a total population of approximately 105 for the Wicklow hills. Numbers since then have prospered because counts in June and August 1971 found a minimum of 168 and 187 respectively in the Wicklow upland area.40
It is remarkable that there was no published systematic work on the diet of red deer in Ireland until 1993 when Sherlock & Fairley gave an account of the food of a small herd (a stag, five to seven hinds and calves) living in a 24 ha enclosure of open terrain, at Mweelin in the Connemara National Park, Co. Galway.41 The altitude ranged between 60 m to a maximum of about 120 m. The vegetation of the this area comprised 36% grassland/heath, dominated by heather and purple moor-grass; 35% peatland, dominated by purple moor-grass, common cottongrass, black bog-rush, bog asphodel and bog-myrtle; 16% grassland/bracken, dominated by bracken with the main grass being Yorkshire-fog and 13% grassland, comprised mainly of creeping bent, Yorkshire-fog, mat-grass, sheep’s fescue and sedges of the genus Carex. The food of the deer was determined by faecal analysis of 50 samples collected over one year. Grasses were the main food, forming at least 75% of the diet – primarily sheep’s fescue, creeping bent, sweet vernal-grass and Yorkshire-fog. The last three species were eaten most in summer and least in winter. Purple moor-grass, the dominant grass of the area, was only of importance in early summer when most palatable. Heather, the second most important food, was mainly eaten in winter. The diet of the Connemara red deer was comparable to that of the red deer living in the Scottish Highlands.
The goat is a frequent inhabitant of many Irish mountains. Here they are feral, having descended from domestic stock, either escaped or turned out by farmers mostly in the early part of this century. When in the wild for several generations, and sometimes within ten years, domestic goats revert to the wild or feral form. Those that have lived in the wild longest are shaggiest, wearing less patterned coats than their domesticated cousins. Despite the modern dairy goat weighing approximately twice that of the feral variety, there is no evidence to support a common assertion that feral goats represent a throw back to a wild type or ancestor of the modern goat. The degree of genetic purity of feral goats is considered high if there are no hornless adults and if none of the goats have small dangling tassels of hair on either side of their throats. Both these features are relatively recent characteristics of modern domesticated goats.
Many goats that were released into the wild have bred successfully to form small herds which have maintained and, in some cases, increased their numbers during the past hundred years. Feral goats are thought to live for about 12 years and weigh, on average, about 51–63 kg. They are browsers on vegetation, rather than grazers, and can cause damage to trees by stripping off the bark, especially during cold weather – ash, elm, yew, rowan, holly and hazel are favourite species to nibble. Lever remarks that approximately 20 goats living on the cliffs of Rathlin Island, Co. Antrim, are possibly the descendants of some liberated in about 1760, while those on Achill Island, Co. Mayo, also date from about the mid-eighteenth century.42 In the Mullagh More area of the Burren, Co. Clare, a lowland herd of approximately 60–70 feral together with domestic goats wander and feed off the limestone pavement and in hazel scrubland. They move around in sub-groups with considerable interchange of individuals between the different herds. They also welcome more domesticated beasts in their midst, thus demonstrating the openness of the feral gene pool to new blood. Rutting starts about mid-September, intensifies in October, and is over by the end of December. The first kids are born five months after mating. A feature of the Burren goats is the unusually high survival rate of kids. The availability and high nutritional status of the food supplied by the karst environment – despite appearing rather impoverished to the layman – probably accounts for such healthy results.43
Feral goat.
The goat in Ireland is celebrated as the central figure in the ‘Puck Fair’, a ceremony dating back to at least 1613. A male goat is first crowned as Tuck King of the Fair’ and then ‘His Majesty Puck King of Ireland’. According to Murray, quoted by Whitehead,44 the name Puck is a derivative from the Slavonic word bog, which means God.
The Irish hare, once considered to be a separate species until a critical examination demoted it to the rank of a subspecies Lepus timidus hibernicus of the mountain hare, occurs only infrequently and at very low densities on Irish mountains. When disturbed from its ‘form’ or day resting place on the hillside, it takes off madly, sometimes pausing upright on its hind legs to examine the intruder, to another distant destination on the mountain. In northwest and west Scotland these mountain hares frequent the arctic and alpine zones of the high summits, sheltering there amongst the boulders. Further south in northern England, in the Peak District mountains, the species is generally confined to the heather and cottongrass in vegetation zones that are found between 300 and 550 m above sea level. On the Isle of Man, a sort of halfway house to Ireland, they are restricted to a generally lower altitude, between 153 and 533 m. In Ireland the hares seem happiest on even lower mixed farmland habitats. Here they have little or no competition from the brown hare, normally absent from these parts. On the lowland Irish