386 BRITISH BIRDS. 



the blotches are coufluent, and form in some instances an irregular zone 

 round the large end. The underlying markings^ which are often large 

 and generally very conspicuous^ are inky grey. Some eggs are much 

 more sparingly marked than others^ some are heavily blotched^ whilst 

 others are uniformly marked with small spots and a few streaks. They 

 vary in length from 2"5 to 2'2 inch, and in breadth from 1*7 to 1"5 inch. 

 Many eggs of the Black Guillemot very closely resemble those of the 

 Sandwich Tern ; but usually the tinge of green on those of the former 

 species is sufficient to identify them. The eggs of the Black Guillemot 

 are always heavier than those of the Sandwich Tern, the smallest 

 weighing more than fifty grains, whilst the largest eggs of the latter 

 species never quite reach that weight ; the site in which they are laid 

 also prevents any possibility of confusion. Both birds assist in the 

 duties of incubation, but the male is said to feed the female while she is 

 sitting on the eggs. 



When its breeding-grounds are invaded, the Black Guillemot betrays 

 but little anxiety, and is often remarkably tame, allowing the observer to 

 approach the rock-crevices ere it takes flight. At the report of a gun 

 the little birds appear at the entrance of the crevices, and peer restlessly 

 about in search of the cause of alarm, and, if further disturbed, numbers 

 dart out from the rocks with whirr of wing on their way to the sea. 

 The young are said to remain in the crevices until almost fledged, and 

 shortly after they visit the sea they are abandoned by their parents. 

 The young birds are easily tamed, soon becoming engaging pets, but 

 rarely long survive their capture. In autumn the young appear to 

 congregate in flocks apart from the adult birds, and wander far from their 

 birthplace. The old birds do not stray so far from home as the Razorbills 

 and Guillemots, preferring to frequent the rocky coasts, bays, and fjords, 

 although they have been noticed many miles away from land. 



The Black Guillemot is about as large as a Puffin, but is a much smaller 

 bird than the Common Guillemot. There is no diff'erence in the colour of 

 the sexes. In full breeding-plumage its colour is, as its name implies, a 

 uniform black, slightly glossed with green, but the median and greater 

 wing-coverts are white, with concealed black bases ; the basal half of the 

 inner web of the primaries is white, and the under wing-coverts and axil- 

 laries are also pure white. Bill black, red at the base; legs and feet 

 vermilion ; irides hazel. After the autumn moult the head and hind neck 

 arc white, mottled with black ; the lower back, scapulars, and upper tail- 

 coverts are black barred with white ; and the run)p and the whole of the 

 underparts are i)ure white ; but the wings and tail remain as in breeding- 

 plumage. Young in first plumage closely resemble adults in winter 

 [)lumage, but there is more brown on the head and neck, and the white 



