(330) ON THE BIRDS OF THE ISLANDS OF OIGH-SGEIR AND CAUSAMUL, NORTH . BY R. B. FREEMAN. A SHORT visit was paid to these two islands on July ioth, 1939. Oigh-sgeir, called alternatively Heiskeir or Haskeir, lies seven and a half miles west of the north-west point of , Outer (O.S. 1* 22), in lat. 57° 42' N. and long. 70 41' W. It is a small rocky island of Lewisian gneiss, half a mile long and less than a quarter of a mile wide at the widest part. The highest point is 123 ft. above sea-level. The map given is modified from the 6-inch

ISLAND OF OIGH-SGEIR, NORTH UIST, HEBRIDES. Modified from O.S. 6", North Uist, Sheet XXIV. Scale 8" = 1 mile Barred areas represent Guillemot cliffs. Figures represent numbers of Fulmar nests, in the approximate position of each group. VOL. XXXIII] BIRDS OF NORTH UIST. 331 O.S. To any one visiting the island in future, it may be well to state that the only convenient landing place is that marked on the map, to the south-east side of the central natural arch. The only indication of human interference is a small hollow circular dun, now in ruins, on the north plateau. Much of the island is bare rock but the two plateaux have a good plant covering, and there is some plant growth on the more sheltered east side of the central ridge. Plantago maritima, with large, spatulate, erect leaves interspersed with Silene maritima and Armeria maritima cover the plateaux, and more clumped, stocky forms of these three grow in the crevices of the rocks. The only other phanerogamic plants observed were Glaux maritima, Cochlearia officinalis, Cheno- podium sp., Matricaria Chamomilla and an unidentified grass. The following birds were recorded. Only in the cases of the Fulmar and Guillemot was any careful attempt made to assess numbers,- but rough estimates are given for other species. ROCK-PIPIT (Anthus spinoletta meinertzhageni).—One pair on the north plateau with nest and four young, in a cavity of the dun remains ; two pairs on south plateau, one with four hopping young. SHAG (Phalacrocorax a. aristotelis).—Probably fifty to sixty nests with young and eggs, mostly in very accessible places, and many on flat ground ; several hundred adults. LEACH'S FORK-TAILED PETREL (Oceanodroma I. leucorrhoa).—A single bird was put up from a hole at the base of the dun on the northern plateau. The hole, which was through an Armeria tuft and under a stone, was examined but contained nothing, nor, except for the entrances did it appear to have been worked at all. Similar holes and crevices at the base of the dun were examined but no more birds were seen. FULMAR PETREL (Fulmarus g. glacialis).—-Sixty-two nests with eggs or young were counted ; the map shows their distribution. None of these was on the cliffs but on gentle slopes or flat ground. One with a sitting bird, was in the dense Plantago in the middle of the dun. OYSTER-CATCHER (Hcematopus o. occidentalis).—One pair north end with chick; one pair south end. COMMON GULL (Larus c. canus).—A few about; none nesting. HERRING-GULL (Larus a. argentatus).—-A few score particularly at the south end. LESSER BLACK-BACKED GULL (Larus f. graellsii).—A few nesting pairs on the north and south plateaux. GREAT BLACK-BACKED GULL (Larus marinus).—Two birds at the south end. KITTIWAKE (Rissa tridactyla).—-About four hundred nests on the four cliffs. RAZORBILL (Alca t. britannica).—-A large number on the tops of the cliffs and also under boulders on the plateau. GUILLEMOT (Uria a. aalge).—-Confined to the cliff edges in the four areas marked on the map. The total population was not above 2,000, of which 1,247 were examined to get an estimate of the frequency of the bridled form. The percentage found was 12.7. 332 BRITISH BIRDS. [VOL, xxxm. PUFFIN (Fratermla. a. grabcs) were entirely absent although common in the waters around the island. A mile to the south-west of Oigh-sgeir are five small stacks called together Oigh-sgeir Eagach. They are very inaccessible and the older men of the west side villages maintain that there was once a Gannet colony there. The man who told me this would not be more definite than " a long time ago." There are certainly none there now. Causamul is a very small island lying one and a half miles to the west of the coast of North Uist (O.S. i* Scotland 22), lat. 57° 35' N. and long. 70 37' W. It consists of a circular southern piece rising to 33 ft. with a modern cairn in the middle, and a long rocky spit to the north intersected with tide channels and continued as a reef for half a mile ; a small beach of large shingle is contained within the landward curve of this spit. Only four species of birds were seen breeding. Twenty-eight Eider (Somateria m. mollissima) nests, many with deserted eggs, were counted in the dense Matricaria growth of the island proper; a few Eider with young were seen on the water. Black Guillemot (Uria g. grylle) were nesting in the interstices of the cairn and under its surrounding rocks; a flock of about 30 birds was seen on the water. The shingle beach had a small colony of Arctic Tern (Sterna macrura), and two nests of the Common Gull were found amongst it. Two Black-headed Gulls (Larus r. ridibundus) were flying with the Terns, this being rather an exposed place for this species compared with their usual distribution in the Hebrides. The only other birds seen were, two Rock-Pipits, a single Oyster-catcher and a few non-breeding gulls.