WHISKERED TERN. 7 



inner webs also wliite; crown of head and nape black ; under 

 surface of body slaty-grey, deepening into blackish towards 

 the abdomen and paling into white towards the chin ; sides of 

 face from the base of the bill to the sides of the neck white, 

 forming a band which contrasts strongly with the black head 

 and grey cheeks ; under tail-coverts, under wing-coverts, and 

 axillaries, pure white or with a slight tinge of grey on the latter; 

 "bill blood-red; feet vermilion, drying to orange colour" 

 {Sainiders). Total length, 10*5 inches; culmen, i't, ; wing, 

 9 "3; tail, 3-45; tarsus, 0-9. 



Adult Female.— Similar to the male, but somewhat paler in 

 colour. Total length, 97 inches; wing, 8-9. 



Adult in Winter Plumage. — Differs from the summer plumage in 

 being white underneath, and in having a white collar round the 

 hind neck; crown of head white, mottled and spotted with 

 black on the hinder crown and nape, and the upper surface 

 paler grey. 



Young-. — Differs from the winter plumage of the adult in 

 having the hinder part of the head blacker, and the upper 

 surface of the body mottled with large or small black spots 

 which are varied with sandy-buff spots or bars. 



Nestling. — Sandy-buff, inclining to golden-buff on the fore- 

 head and mantle ; the upper surface prettily striped or spotted 

 with regular lines of black ; the throat sooty black ; rest of 

 under parts white, the sides of the body being sandy-buff. 



Characters. — The adult bird is easily distinguished from 

 H. leucoptera by the grey upper and under tail-coverts, and 

 from H. nii^^ra by the red bill and white chin and sides of face, 

 as well as by the white under wing-coverts. In winter plumage 

 the species may be distinguished from the adult of H. leucoptera 

 by its grey tail, and from the young of the latter species, which 

 has a grey tail, by the absence of white on the rump, which is 

 to be found in the young of the White-winged Black Tern. In 

 winter plumage H. hybrida has a grey rump, like the back, and 

 it thus resembles the winter dress of H. 7iigra^ but it is a 

 larger bird than the latter, has a stouter bill, and has the webs 

 of the feet much incised. 



