542 FALCO 



are white somewhat sparingly blotched with reddish orange, 

 whilst others are more profusely blotched with dull, almost 

 chestnut-red. In size they measure about 2 '28 by 1'81. 



Of Hierofalco uralensis, Severtz and Menzbier (Orn. Geogr. 

 Europ. Ross. i. p. 288, 1882) (H. grebnitzkii, Severtz) which 

 appears to be very similar to, if not identical with, the present 

 species or F. gyrfalco, I have not been able to examine a 

 specimen. 



760. LORENZ'S GYRFALCON. 

 FALCO LORENZI. 



Falco lorenzi, Menzbier, Bull. B. 0. Club, xi. p. 3 (1900). 



ad. Eesembles the northern Gyrfalcons in its plumage, the general colour 

 of the upper parts being bluish, and it is barred like them, but it has the 

 tarsus bare on more than half its length as in F. milvipes y to which it is 

 said to be nearly allied, but differs conspicuously in colour. 



Hob. Tomsk and Yeneseisk in Siberia. 



Nothing is known respecting this bird except that three 

 specimens were obtained in winter in the above named 

 localities. 



761. ALTAI GYRFALCON. 

 FALCO ALTAICUS. 



Falco altaicus (Menzbier), Orn. Turkest. p. 272 (1891). 



ad. Differs from F. gyrfalco in having the upper parts reddish brown 

 washed with ash, the under parts ochraceous with tear-shaped dark brown 

 stripes ; tail brown, tipped with pale ochreous, the two middle feathers un- 

 barred, the rest with indistinct oval transverse reddish brown spots ; 

 tarsus bare for more than half its length; bill bluish horn, yellowish at 

 the base ; cere and legs yellow. The young female differs from F. gyrfalco 

 in having the crown, head, and upper parts dark brown with a few obsolete 

 d,ull buff spots and bars, the tail barred with greyish buff, the under parts 

 brown, the flanks and thighs barred, the rest of the under parts spotted 

 and striped with buffy white. Culmen 2'0, wing 14*6, tail 9' 10, 

 tarsus 2-2 inch. 



Hob. The mountain ranges bordering the plateau of Central 

 Asia on the north and west. 



I find nothing on record about the habits and nidification of 

 this bird, but an egg, obtained in the Altai mountains with the 

 parent bird, and now in my collection, resembles dark eggs of 

 F. candicans, but is smaller, measuring 2*16 by 1'67. 



