LAEIDa3 LABUS 425 



bodies of Whales or Seals and also picking up worms, insects and 

 shell fish from the beach ; it is said to carry off the eggs of other 

 sea birds such as Gannets and Penguins to distant rocks, where it 

 devours them at leisure. 



This Gull has a loud and melancholy call heard generally in 

 early morning when flying round; during the day time it can 

 frequently be seen standing motionless on the sandy beach for 

 hours at a time. 



The Southern Black-backed Gull breeds on the islands off the 

 north-western and southern coasts. Its nest is formed on the 

 sandy beach as a rule and contains from two to three eggs ; these 

 vary considerably in colour and markings but are usually pale green 

 with a more or less pronounced tinge of brown moderately spotted 

 and blotched with very dark brown and with underlying spots of 

 pale purplish-brown ; they measure on an average 2-70 X 2-0. 



There are eggs in the South African Museum taken by myself on 

 Dyer's Island off the coast of the Galedon district, on December 3, 

 but the birds mostly breed in November. 



755. Larus hartlaubi. Harllaub's GiolL 



Gavia hartlaubi, Brucli. Journ. Ornith. 1853, p. 102. 



Larus poiocephalus, (nee Swains.) Layard, B. S. Afr. p. 368 (1867). 



Larus hartlaubi, Saunders, P. Z. S. 1874, p. 293, 1878, p. 188, fig. 5; 

 Sliarpe, cd. Layard' s B. S. Afr. p. 698 (1884) ; Swinburne, P. E. 

 Phys. Soc. Edin. ix, p. 200 (1886) ; Saunders, Cat. B. M. xxv, p. 240 

 (1896) ; Shelley, B. Afr. i, p. 165 (1896) ; W. L. Sclater, Ibis, 1896, 

 p. 521 ; Beichcnoiu, Vbg. Afr. i, p. 45 (1900) ; Oates, Cat. B. Eggs, i, 

 p. 211, pi. xvii, fig. 2 (1901). 



Description. Adult Female. — Head and neck all round, whole 

 of the underparts and tail white ; mantle and wings lavender grey ; 

 first two primaries black with the usual subterminal white marking, 

 the third to fifth with the basal halves white, seventh uniform grey 

 fringed with smoky on the inner web, under wing-coverts uniform 

 smoke grey. 



Iris white to light brown ; eyelids red ; bill and feet red. 



Length 15 ; wing 10-75 ; tail 4-0 ; culmen 1-25 ; tarsus 1-70. 

 Young birds have no 'subterminal white markings on the outer 

 primaries ; all the primaries except the first are distinctly tipped 

 with white and the mantle and wings are mottled with brown ; 



