Skomer part 3

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Manx shearwaters return to the colonies during March, occupying burrows right across the islands in which a single egg will be laid in late April/early May. The incubation period of some 51 days is shared about equally by both parents as indeed is the task of bringing food to the chick during a fledging period of 72 days. At the end of which chicks can weigh half as much again as an adult. Such a reserve is essential. Firstly there is a starvation period before the fledgling leaves the island during early September. Then follows an immediate and rapid journey, one of at most barely several weeks duration to South Atlantic fishing grounds 6,000 miles (10,000km) away off the coasts of Brazil, Uruguay and the Argentine. Indeed the Manx Shearwater is the only bird breeding in Great Britain which migrates to South America and this will be the first of numerous journeys, up and down the Atlantic, for Manx Shearwaters are long-lived, and quite a few will reach their thirtieth year.

Guillemots and Razorbills, are very obvious on the cliffs from early May until late July, their season ashore even shorter than the Puffin, although both make sporadic visits, normally during spells of settled weather, from early winter onwards. It is hardly surprising that birds nesting in such precarious situations as open ledges and cliff niches without any nest should have evolved so the chicks remain ashore for no more than 21 days after hatching. Better for the chicks to complete their fledging at sea than in the jostling cliff communes. Boisterous, at times argumentative adults and the threat posed by predatory gulls, are two hazards best avoided, while adults are saved the energy sapping task of flighting back to the colonies with food.

Often sharing the same cliffs as Guillemots and Razorbills, sometimes nesting at the lowest levels is the daintiest of gulls, the Kittiwake, dainty to look at, but noisy, with raucous, screaming "kittiwake-kittiwake" calls. Calls often magnified by the cliffs themselves, especially at the great chasm of The Wick, one of the finest seabird cliffs in north-west Europe. Like the other seabirds, Kittiwakes once the breeding season is over leave the cliffs, many spend the winter roaming the North Atlantic.

There is one other cliff-nesting seabird that must not be overlooked, though it is quite easy to do so, for the less observant might mistake a Fulmar for a gull. Look again and immediately note the differences, the tubular nostrils and dark eyes. The bull neck, and the habit of shuffling rather than standing on the cliff ledge. Then in flight, the true master of ever swish of air, every air current, every turbulence, every draught along the cliff-face it seems is there to be enjoyed. Stand at the head of The Wick, stop watching Puffins for a moment, leave the hub-hub of the Guillemots, the Razorbills, the Kittiwakes and look at the high ledge just above eye-level. Here a dozen or so Fulmars nest and birds will silently come and go, sweeping effortlessly along the cliff-face, or on swooping upwards towards the ledge suddenly hang in the air and then sweep away again. Few birds emulate such mastery, none surpasses it, for the Fulmar is the grey-glider of the North Atlantic.

A few hundred pairs of Herring Gulls nest on the cliff-slopes, while an even smaller number of that robber baron of seabird colonies, the Great Black-backed Gull occupy the lofty knolls and ridges. Their cousin, the Lesser Black-backed Gull is the most numerous of the gulls here, with numerous large noisy colonies across the plateau and on some cliff slopes. All three have the same nesting cycle, incubation of the three eggs takes about 28 days, eggs incidentally once collected in large numbers for food by earlier islanders and the villagers of Marloes. The chicks fledge at seven weeks, these are the grey-brown gulls with rather squeaky voices which are such a feature of the Pembrokeshire coast from mid-July onwards

Other nesting birds include the noisy Oystercatchers while in the central valleys are the only Curlews which still nest in Pembrokeshire. Up to four pairs of Choughs nest as do several pairs of Ravens. The absence of trees seems no deterrent to some birds. Magpies seem just at home in a bramble bush while Wood Pigeons happily nest on the ground. The small birds include Skylark and Meadow Pipit in the fields, Rock Pipits around the coast and Pied Wagtails, Wrens, Hedge Sparrows, Blackbirds, Sedge Warblers and Whitethroats wherever there is suitable habitat. Breeding birds of prey are Buzzard, Kestrel, Peregrine and Little Owl, the latter to be frowned upon because it has decimated the Storm Petrel population on Skomer, and the Short-eared Owl. This one of the stars of Skomer, in May and June often to be seen by day quartering the central valleys as it hunts for food for hungry chicks. Up to 14 pairs have nested on occasions, though the number is usually much less than this.

One of the main prey items for the Short-eared Owls is the islands special mammal the Skomer vole. A unique island race of the Bank Vole, only found on Skomer, where, in the absence of ground predators, it thrives in the areas of deep Bracken. How long it has been present no one knows, but clearly long enough, perhaps several thousand years, for it to exhibit significant differences with its mainland cousin. The distinctly larger size, bright upper-parts and silver-grey underparts, and a most confiding nature once caught, are immediately obvious. By late summer each year there may be as many as 20,000 present, but though the owls see them the chances of a visitor doing so are rather remote, and at best but a fleeting glimpse.

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