1 82 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



p. 135 (1865: Isl. of Chiloe); Scl. & Salv. Ibis, 1869, p. 284 (St. 

 lago Bay, Dec), 1870, p. 500 (Coquimbo, Aug.); iid. P. Z. S. 1871, 

 p. 570 (Falkland Is. and Straits of Magellan) ; Cunningh. Nat. Hist. 

 Str. Magell. pp. 74, 404 (1871 : Santiago Bay) ; Scl. & Salv. Nomencl. 

 Av. Neotr. p. 147 (1873); iid. P. Z. S. 1873, p. 147. 



General description. 



Size (adult). — Total length, 16 to 16.5 inches. 



Wing, 1 1.8 inches. 



Tail, outer feathers, 7.0 inches. 



Tail, depth of fork, 3.9 to 4.0 inches. 



Culmen, 1.75 inches. 



Tarsus, 0.8 inches. 



Color (adult breeding). — General color above pale pearl grey ; a black 

 cap ; below lighter pearl grey, becoming white posteriorly. 



Head : A black cap reaches from the forehead to the occiput, including 

 the greater portion of the lores. This cap is bordered by a pure white 

 streak from the gape backward. 



Neck : Pale pearl grey above, lighter beneath. 



Back (mantle): Pale pearl grey. Rump white. 



Wings : Like the mantle, the inner primaries and secondaries broadly 

 margined with white. 



Tail : White, the outer webs with a pale grey tinge. 



Lower parts : Pale pearl grey, lighter than the mantle and becoming 

 pure white in the region of the vent and lower tail coverts. 



Bill : Vermilion. Legs and feet vermilion. Iris brown. 



"Male: Tom Bay, November 30, 1879. Bill, legs, and feet red. 



"Female: Cockle Cove, October 16, 1879. Bill and legs red; claws 

 black; iris dark." Sharpe, P. Z. S. 1881, p. 16." 



Adults in winter differ in being slightly paler above ; the crown is 

 mottled with white, and the under parts are nearly or quite white. This 

 plumage is very transitory. 



Young birds of the year are similar to the adults in winter, but have 

 more grey on the rectrices and the outer webs of the primaries are much 

 deeper grey. Bill, legs and feet reddish brown. Younger birds have a 

 brownish bar across the upper wing coverts and the mantle is barred 



