NOTES ON BIRDS OBSERVED AT THE BUTT OF LEWIS 79 



heard every year, nth May in 1908 being the earliest record, 

 other years a week later. In 19 10 about forty pairs bred here, 

 leaving their breeding rock on 7th August. 21st September 1912 

 was the date of their latest presence, when they, or the common 

 species, were flying noisily round the lighthouse lantern. 



Common Tern [Sterna fluviatilis). — Not so common as the 

 Arctic species, but a few are seen and a few breed every year. 



Black-headed Gull {Larus ridibundus'). — The six or eight 

 pairs which breed here have been seen as early as 20th January in 

 1 91 3, and February and March in several years, and in September 

 and October. If they do leave at all it is only for a short time. 

 Their comings and goings have never been particularly noticed. 



Common Gull {Lams canus). — Never numerous here, but two 

 or three pairs have for several years nested beside the lighthouse. 

 One was killed at the lantern in March 191 1. 



Herring-gull {Lams arge)itatus). — Always resident here. 

 Their time of nesting is greatly influenced by weather conditions, 

 but earliest noted is 15th May, and the young are in flight early 

 in August. 



Lesser Black-backed Gull {Lams fuscus). — Six or eight 

 pairs breed on outlying rocks, in single pairs, at different places. 

 Their exact time of coming and going has not been observed. 



Great Black-backed Gull {Lams martmts). — I have seen 

 several small nesting colonies of these on the East Lewis cliffs not 

 far distant. A good many young birds are seen here in August and 

 September, and adults forage round all winter, braving the wildest 

 of gales. 



Glaucous Gull {Lams glaiicus). — This large creamy-white 

 species has been observed here on several occasions, 2nd March 

 1 9 14 being the latest record. 



Iceland Gull {Lams leucopterus). — This winter visitor has 

 also been observed here on one or two occasions. 



KiTTiWAKE {Rtssa tridadyki). — In three small colonies about 

 live or six hundred nest here. Arriving in March they resort to 

 outlying rocks before taking to their breeding cliffs. Late in May 

 or early in June they begin simultaneously to carry nesting material, 

 but owing to nests being robbed of the eggs by other gulls or grey 

 crows, or destroyed by the sea, and a second clutch being necessary, 

 it is generally the first week in September before the last youn^^ leave 

 the cliffs. They all soon afterwards disappear. 



Richardson's or Arctic Skua {Lestris crepidatus). — This is the 

 only Skua I have observed here, and that only on a few occasions. 



Razorbill {Alca forda). — Razorbills are seen all through the 



