BLACK-HEADED GULL. 
59 
V. THE BLACK-HEADED GULL. LARUS RIDIBUNDUS. 
Lams ridibundus, Linn. Syst. Nat. i. p. 225 (1766); Dresser, 
B. Eur. viii. p. 357, pis. 596 and 597, fig. i. (1878) ; 
B. O. U. List Brit. B. p. 19 1 (1883); Saunders, ed. 
Yarrell’s Brit B. iii. p. 594 (1884); Seebohm. Hist. Brit 
B. iii. p. 310 (1885); Saunders, Man. Brit B. p. 649 
(1889); Lilford, Col. Fig. Brit B. part xxi. (1892); 
Saunders, Cat. B, Brit. Mus. xxv. p. 207 (1896). 
Gavia ridibunda, Macgill. Brit. B. v. p. 593 (1852). 
Gavia capistrata, Macgill. t.c. p. 605. 
(Plate XCIX.) 
Adult Male. — General colour above delicate pearly-grey, 
including the wing-coverts ; the marginal coverts pure white, 
as also the bastard-wing and primary-coverts, the latter slightly 
shaded with pearly-grey on the inner feathers ; the three outer 
primaries white, with white shafts, black tips, and black edging 
to the inner webs ; the first primary black along the outer web, 
the second and third also, with a n.arrow line externally ; 
remainder of the primaries grey, with black tips and black 
margins to the inner webs, the black disappearing gradually on the 
inner primaries, which have a termin.al spot of grey ; the fifth pri- 
mary white on the outer web, the secondaries entirely grey ; lower 
rump, upper tail-coverts, and tail white ; crown of head as far 
as the nape, sides of the face, and throat chocolate-brown, 
darkening towards the edges of the hood, which is very well 
defined ; a ring of white above and behind the eye ; hind-neck 
from the nape and sides of neck white, slightly overspreading 
the mantle •, entire under surface of body from the lower throat 
downward white, with a slight rosy tinge, including the 
axillaries and marginal lower wing-coverts; the lower, median, 
greater, and primary-coverts grey ; “ bill, tarsi, and toes lake- 
red ; iris hazel” {H. Saunders). Total length, i6‘5 inches; 
culmen, i'45; wing, ii'9; tail, 475; tarsus, 17. 
Adult Female. — Slightly smaller than the male, as a rule. Total 
length, i4‘5 inches; wing, ii'8. 
Adult in Winter Plumage. — Differs from the summer plumage in 
lacking the brown head, the crown being white with a little 
