BLACK GUILLEMOT 491 



Nest. Early in April this bird seeks for its breeding- 

 quarters, the quietude of rock-fissures in cliffs of very 

 varying altitudes, though never at a great height above 

 the sea-level. It keeps apart from the throngs of Common 

 Guillemots, Kazorbilis, and Kitti wakes, nevertheless, I have 

 seen all four species breeding within the confines of one 

 small island. I have 'found the nesting-cavity in a deep 

 hole at the base of a cliff only a few feet above the sea-level. 

 This Guillemot also breeds under masses of loose stones, 

 especially on low, flat islands, I have records of odd pairs 

 nesting on the mainland of the Dublin coast, as well as on 

 Lambay Island and Ireland's Eye, though along the east 

 side of Ireland it breeds but sparingly. 



Colonies, strictly speaking, are not formed ; yet in very 

 favoured localities such as along the Galway coast where 

 the great solid rocks are freely fissured, several pairs may 

 be found breeding in close proximity. The eggs are laid in 

 May and are two in number. The ground-colour is white ; 

 in some specimens very faintly shaded with bluish-green, 

 and the blotches vary from light to dark brown. 



Both sexes incubate. 



The young quit their nest about the middle of July and 

 appear to be sufficiently matured to look after themselves 

 almost as soon as they take to the water. According to 

 some observers the parent-birds continue to feed them for 

 some time afterwards. 



In an adult male were remains of Portunus arcuatus (a swimming 

 crab), some of these creatures being almost entire : the largest measured 

 14 mm. across the carapace (body-shell), the smallest 10 mm., also 

 fragments of larger crustaceans too broken up to allow of identification : 

 several pieces of Litlio-thammia (a stony weed) were present. 



The stomach of an adult female contained the greater part of a 

 Hermit-crab (Pagurus bernhardus\ with no shell surrounding it and 

 with one of the large claws missing, probably pulled off, as the bird tried 

 to extract the crab from its shell. Portunus was also found, the largest 

 carapace measuring 17 mm. 



The stomach of another adult female contained Paguridce, several 

 forms of Brachyura, and remains of other unidentified crustaceans. The 

 gizzard of a young male contained Portunus arcuatus in large quantities, 

 also the claw of a Pagurid, the claw of Procellana longicornis, and the 

 remains of Galathea squamifera. All these birds were obtained from 

 the same locality, viz., Ballynakill Bay, co. Galway, and on the same 

 date, April 13th, 1900. I was surprised to find no fish present in the 

 stomachs, and from the nature of the food it seems obvious that these 

 Guillemots must have descended to a considerable depth to pick the 

 creatures from the floor of the sea or from submerged rocks. 



