(2) THE IVORY-GULL IN SPITSBERGEN. BY C. T. DALGETY (Plate I.) MY first view of the Ivory-Gull (Pagophila eburnea) was on July 30th, 1927. We were on the east of the Spitsbergen group, passing through Freeman Strait between Edge Island and Barents Island. The sun shone brilliantly, touching the ice with myriad hues of blues and greens. Wooden- winged Fulmars were wheeling everywhere. Glaucous Gulls, Kittiwakes, Little Auks, and Brunnich's and Mandt's Guillemots were continually passing by. Then three Ivory- Gulls appeared. Their extreme whiteness was the first thing to strike me; " white as snow " is a common expression, but here was something whiter than snow. During the next month we continually saw Ivory-Gulls flying and feeding along the shore, but never did I see one on the water. When feeding on the shore, they would run forward as each wave receded, always jumping back to avoid being wetted by the next. Since that year I have seen many more Ivories, but I have never seen one on the water. They are essentially birds of the ice, if the ice goes away they become birds of the shore. Their beautiful appearance is not in keeping with their habits, for they are the vultures of the arctic ; their food consisting of remains of seals and bears, carcases killed by bear or man, and any other fish or animal remains. I first saw a breeding colony on August 16th, 1927. The nests were on a very small dolerite cliff, at an altitude of 1,700 feet, within 150 feet of the top of a steep high scree slope which formed one side of a valley running six miles down to the sea. There were many nests and twenty old birds, but only two young, which were almost fledged. They were white with black spots about the size of one's finger nail. In 1930 and 19311 went again to Spitsbergen, and saw more of these birds. On the mainland of West Spitsbergen we often saw them in Liefde Bay, on the north, and occasionally in Ice Fjord, in the centre. At the latter place an odd bird or two would appear in stormy weather, but in Liefde Bay there were usually two or three. Here I shot one which proved to be a male with a large incubation patch. In Pallander Bay, a branch of Wahlenburg Bay in North East Land, we found a breeding colony which we visited on July 6th, 1930, and July 8th, 1931. This colony was at an VOL. xxvi] IVORY-GULL IN SPITSBERGEN. 3 altitude of 1,000 feet, nearly at the top of a cliff that overlooked the bay. Here there were over thirty pairs. In 1930 half the occupied riests contained single eggs and half contained pairs. In 1931 one nest contained three eggs while only three had single eggs which were all fresh ; the remainder had pairs.

Cliit with Ivory-Gull Colony, Palander Bay, North East Land. (Photographed by C. T. Dalgety.) In 1930 there was exceptionally little ice, while in 1931 there was quite as much as usual. It seems possible that this may have been the cause of the smaller clutches in 1930, as the Ivories get most of their food on the ice. There was, in most cases, a slight difference in the time of incubation of eggs from the same nest. 4 BRITISH BIRDS. [VOL. XXVI. The nests were mostly built of land plants, moss, grass, saxifrage, etc. ; but a few were mere hollows in the grassy turf. This turf was only present where the Ivories were nesting, and appeared to consist of old nests which had taken root in the remains of still older ones. Many of the nests were

Ivory-Gulls and Nests on Great Island. (Photographed by J. H. McNeile.) under the shelter of overhanging rocks. One or two Kitti- wakes had nests among the Ivories, and there was a large colony of Kittiwakes close by. The cleanliness of the Ivories made a striking contrast with the filth of the Kittiwakes ; there was no dirt on or near the nests of the former. This made the colonies distinguishable from some way off on the VOL. xxvi] IVORY-GULL IN SPITSBERGEN. 5 ice of the bay ; the grey Kittiwakes were difficult to see against the whitewashed rocks, but the white Ivories showed up plainly against the dark rock and green turf. Mandt's Guillemots were nesting in the cracks amongst the Ivory colony. On July 20th, 1930, we found a colony on Great Island, to the north-east of North East Land. Here, at an altitude of about two hundred feet and within a few yards of the foot of the ice cap, there were eleven nests on a dry stony ridge. These nests were made entirely of moss, the only land plant available on that barren island. Five nests contained two eggs each, some of which were only slightly incubated, while five contained single eggs, all of which were much incubated. One nest contained one chipping egg and one young one, covered with a uniform pale grey down. Twenty-one birds were here and all stayed near the nests, screaming and occasionally stooping at us. A few others passed by without demonstration, so presumably did not belong to this colony. I have only once seen a bird arrive at or leave a colony, this was at the colony on Edge Island, where there were only two young between twenty old birds. Other observers have noticed the same thing, and it is a mystery how the incubating bird or the young get sufficient food. The bird shot in Liefde Bay tends to show that incubation is by both sexes, and that the one which is not sitting spends a long time in search of food. But at this Great Island colony there was only one bird missing from the eleven pairs. Though birds continually stooped within a few inches of me at all the colonies I visited, they never actually struck me. Other observers have been struck repeatedly. While I was trying to photograph the birds at Pallander Bay in 1931 there was a snowstorm which helped neither the photography nor the climbing. But it did allow us to read the cause of the disappearance of one clutch of eggs. The nest was on a stone not more than two foot square jammed in a right angle corner of the cliff. Above the nest was more than twenty feet of sheer rock, below it more than forty, with no foothold for even a bird. The new snow lay over all the nest except where the bird had been sitting. Why no eggs ? Then we saw the tracks of an arctic fox in the snow on the edge of the nest. How the fox had got there was even more puzzling. Then we found the tracks where lie had looked over the cliff and seen the nest, then gone away for thirty Ivory-Gull at the nest, Palander Bay, North East Land, during a snowstorm. (Photographed by C. T. Dalgety.) VOL. xxvi] IVORY-GULL IN SPITSBERGEN. i yards and down a hole. He must have known of this hole before, and used it for getting other meals. The fox is the only enemy of the Ivory-Gull, for Skuas and other Gulls are easily outflown and the only bird of prey in Spitsbergen is the Snowy Owl, which is very scarce. In 1927 one of the ship's crew caught an Ivory by means of a hook baited with bear's blubber. It lived on deck, wearing jesses and tied to a boot last, and soon became very tame. It was given to the London Zoo but did not live long. The eggs vary in ground-colour from a dark brown to a pale putty colour, with varying tinges of yellowish or greenish, some being a greyish-green with little or no trace of brown. The shell markings are leaden or lavender-grey. The surface markings, which may be blotches, spots or streaks, range from a brown that is almost black to a pale khaki colour. The different combinations of these colours gives a large variation of types. The average measurement of 37 eggs is 60.03 X 42.66 mm. The maximums and minimums being:— Length Breadth f 64.1 x 42 mm. Max. I 58.25 x 44-5 ,. f 54.2 x 41.6 Min. t 57-3 X 40-8 British Birds, Vol. XXVI., PI. i.

A pair of Ivory-Gulls at their nest at Palander Bay, North East Land. {Photographed by C. T. Dalgety.)