152 



BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



PASSERINA NIVALIS TOWNSENDI Ridgway. 

 ALEUTIAN SNOWFLAKE. 



Siiiiiliir to 7*. //. /ti/x/h's, ])ut decidedly larg-er, with relatively long-er 

 bill. 



Adult male.—hQngth (skins), 153.67-188.47 (175.26); wing, 108.71- 

 120.40 (113.03); tail, 66.29-71.17 (70.87); exposed culmen, 12.19-13.16 

 (12.70); depth of bill at base, 6.35-7.11 (6.60); tarsus, 21.81-24.38 

 (23.11); middle toe, 14.48-16.00 (14.99).^ 



AfJuJffeinaJe.—Ijength (skins), 155.70-177.80 (169.16); wing, 102.87- 

 115.82(106.68); tail, 62.23-68.58 (65.02); exposed culmen, 10.92-13.46 

 (12.19); depth of bill at base, 6.10-6.86 (6.60); tarsus, 20.83-23.37 

 (22.61); middle toe, 13.72-15.49 (14. 73).'' 



Aleutian Islands, including Commander Islands, Kamchatka; Pribi- 

 lof Islands; Shuraagin Islands; Siberian coast of Bering Sea (breeding 

 at Ployer Bay, etc.).^ 



Plectrophanes nivalis (not Emheriza nivalis Linnaeus) Dall and Bannister, Trans. 

 ' Chicago Ac. Sci., i, 1869, 282, part (St. Georges I., Pribilof group). — Finsch, 

 Abh. Nat. Ver. Brem., iii, 1872, 54, part (Pribilofs).— Dall, Proc. Cal. Ac. 

 Sci., V, 1873, 27 (Unalaska); vi, 1874, 273 (Attn and other Aleutian islands; 

 Pribilofs) .— CouES, in Elliott's Affairs in Alaska, 1875, 176 (Pribilof Islands, 

 resident; habits). — Hakting, Fauna Prybilov Islands, 1875, 17. — Elliott,' 

 Mon. Seal Islands, 1882, 128 (habits, etc.).— Bean, Proc. U. S. Nat. Mus.,v, 

 1882, 149, part (Shumagin Islands, Alaska; Plover Bay, Siberia). 



' Twenty-two specimens. 



■''Twelve specimens. 



The largest specimens are those from the more western Aleutian Islands, including 

 the Commander Islands, Kamchatka; the smallest are from Unalaska and the Shu- 

 magin Islands, at the opposite end of the chain. These latter are in reality inter- 

 mediate between the island form and true P. nivalis, but seem nearest the former 

 and, therefore, best referred to it. Average measurements are as follows: 



Localitv. 



One adult male from Bering Island 



Five adult males from western Aleutians (Attn, 



Kyska and Adak islands) 



Twelve adult males from Pribilof Islands 



One adult male from Plover Bay, Siberia (breeding 



bird ) 



Three adult males from Unalaska and Shumagins . . 



FEMALES. 



Five adult females from western Aleutians 



Six adult females from Pribilofs 



One adult female from Unalaska 



Middle 

 toe. 



15.49 

 14.99 



14.73 

 14. 73 



14.73 

 14.73 

 14.73 



^Winter birds (some at least) from Plover Bay, also from Unalaska and Shuma- 

 gins, are P. n. nivalis. 



