GREAT BLACK-HEADED GULL. 611 



raven-like croak, and the latter states that the bird is of a 

 very quarrelsome nature. 



The adult in breeding-plumage has the bill orange-yellow, 

 turning to red at the maridibular angle, in front of which is 

 a transverse black bar ; gape and eyelids vermilion ; irides 

 dark brown ; entire head and upper part of the neck jet 

 black ; a white crescentic patch behind the eye ; lower neck, 

 upper back, tail, and entire under-parts, pure white ; wing- 

 coverts and mantle dark grey ; first primary quill-feather 

 principally white, with a black streak along the greater por- 

 tion of the outer web, and a patch of the same colour on the 

 inner web next to the shaft about an inch and a half from 

 the tip ; on the second, third, and fourth primaries the 

 black forms a bar with broad white tips ; upper primaries 

 white, turning to pearl-grey on the inner margins and cen- 

 tres ; secondaries broadly tipped with white, forming a very 

 distinct bar by contrast with the grey wing-coverts ; legs and 

 feet greenish-yellow ; webs orange. 



Total length of a male twenty-seven inches ; wing, from 

 the carpal joint to the tip, nineteen inches. There is, how- 

 ever, considerable variation in size, and females are often 

 so much smaller than the males as to have given rise to the 

 belief that they belonged to a distinct species. Schlegel 

 has described one of these from Bengal as L. ichthyaetus 

 minor, and Mr. A. 0. Hume has apparently distinguished a 

 similar small example by the name of L. innominatus. 



Less mature birds are characterized by the larger amount 

 of black in the primaries ; and in the immature bird, when 

 assuming the black hood for the first time, the primaries are 

 mostly blackish-brown, with only a sub-apical patch of white 

 on the outer one ; the mantle is grey, with brown markings 

 on the carpal joints, and at the tips of the tertials ; tail 

 white with a black bar ; rest of the plumage as in the adult ; 

 bill olive. 



The young bird of the year is mottled with brown on the 

 upper parts, which gradually turn to grey ; and the primaries 

 are dusky-brown ; the secondaries are brown, broadly tipped 

 with white, and they are also margined with white on both 



