54 BRITISH BIRDS. WITH THEIR NESTS AND EGGS. 



entire upper surface, sooty-black ; the forked tail sooty-black, the outermost feather 

 on each side white, with the exception of the terminal half of the inner web which 

 is greyish-black ; bill, legs and feet black, the web between the inner and the 

 middle toe but little excised. Length 16 to 17 inches; ridge of bill 2'o; wing 

 iryo; tail 7*5, and its fork 4'! ; tarsus o'ga. 



The Sooty Tern forms no nest, merely scratching a hollow in the sand or on 

 the bare ground, in which generally a solitary egg is laid, although two and three 

 have been found in one nest. These are smooth and shining, of a white or bluish- 

 white ground-colour to a warm buff, with markings, very variable in amount, 

 consisting of spots or blotches, red-brown or purplish- grey in colour. In dimensions 

 the eggs are about 2 inches in length by i inches in diameter. 



The chicks are, like those of other Terns, hatched covered with down, which 

 is of a brown colour, tipped with white above ; and with the breast and under 

 surface white. " When half fledged," as Mr. Saunders writes, " the feathers of 

 the mantle are blackish, with broad white tips, which gradually wear down. When 

 the bird is fully fledged these white tips are much narrower, the feathers of the 

 upper parts are sooty-brown, and the under parts are also of a somewhat paler 

 brown, becoming lighter towards the vent ; bill and feet reddish-brown." 



The immature birds have their sooty plumage suffused with brown or grey, 

 but much paler underneath ; the upper wing-coverts have white tips ; the tail is 

 only slightly unequal, instead of being forked ; and its outer feathers have their 

 external webs brownish. 



The winter plumage of the Sooty Tern is hardly distinguishable from that of 

 the summer, but on the crown of the head and in the black loral streak there 

 occur a few white feathers. 



These birds are " wonderfully powerful flyers, and must at times be for many 

 days on the wing. Even whilst catering for their young they are supposed to 

 travel great distances, as Mr. Gill, whilst one day at the largest ' fair' [on Ascension] 

 caught a bird in his hand with a small fish in its beak, which was not recognized 

 as an inhabitant of Ascension waters. This bird must have been fishing at some 

 distance" (Penrose). 



After their duties of incubation are over these Terns take their departure, and 

 disperse along the coasts of the continents that may be nearest to them. 



