96 On the Ornithology of St. Kilda. 



on St. Kilda, and is said by the natives to be commonest on 

 Soay. They say it is one of the earliest birds to arrive in 

 spring, and one of the latest to depart in autumn. I obtained 

 a fine series of birds and fresli eggs of this species on Doon 

 on the 10th of June. The place where the Fork-tailed Petrel 

 breeds is on that portion of the island nearest to St. Kilda, 

 and at the summit. The nests were very close together and 

 we found half a dozen in a patch of grassy land perhaps ten 

 yards square. Only one egg is laid, at the end of a burrow 

 precisely similar to that made by the Puffin, and the nest is 

 merely a little half-dried grass. We never found more than 

 one bird in the hole, and both sexes appear to take turns in 

 incubating the egg. The bird when caught emitted a small 

 quantity of oil precisely similar to that vomited by the 

 Fulmar. I took eleven nests of this interesting little bird, 

 but in two holes there was no eg^, although we caught the 

 parent. One hole contained no nest Avhatever and the egg 

 lay on the bare ground. The holes vary considerably in 

 depth, and are made in the soft soil, where it is very easy to 

 uneartli them ; but whether they are made by the Petrels or 

 are disused Puffin's burrows, I am unable to say. Sometimes 

 the hole has two entrances, and one end must be stopped to 

 prevent the bird escaping. Those holes which were inhabited 

 by Petrels generally had a little dry grass at the entrance. 

 The Fork-tailed Petrel is almost exclusively nocturnal in its 

 habits, and keeps close in its hole during the day. The birds 

 which I dissected had been feeding on similar substances to 

 those found in the Fulmar and the Shearwater. Irides 

 dark hazel; legs, feet, claAvs, and bill black. 



Of the sixty-seven species enumerated in the preceding list 

 twenty-seven may be regarded as breeding regularly on the 

 islands, four only breed occasionally, and two or three may 

 breed there but have hitherto escaped noticed (Curlew, Snipe, 

 Briinnich's Guillemot). The remainder are only accidental 

 visitors or pass regularly on spring and autumn migration. 

 I have not the least doubt that the list of occasional visitors 

 would be doubled if we had competent observers stationed at 

 St. Kilda during migration-time. I hope to be able to 



