WHITE GRYFALCON 
353. Falco islandus. 23 in. 
Adults in perfect plumage, pure white, slightly barred 
on the back and spotted below with black. 
Nest.—Of sticks, lined with grasses and feathers; 
placed on ledges of cliffs; eggs bulky white, specked 
with reddish brown, often so thickly that the ground 
color is obscured (2.30 x 1.80). 
Range.—Arctic region, breeding in Northern Green- 
land, and wintering to the Gulf of St. Lawrence, and 
casually to northern Maine. 
GRAY GYRFALCON 
354. Falco rusticolus. 23 in. 
Adults white, heavily barred above, and streaked be- 
low with gray and black. 
Range.—Arctic regions, south in winter, rarely to 
northern United States. 
354a. GYRFALCON (F. r. gyrfaleo). Similar to the 
last but darker, the latter being usually more white than 
dusky, while this is the reverse. 
354b. BLACK GYRFALCON (F. r. obsoletus). Much 
darker than the last, the markings tending to be buffy 
white spots on a grayish black ground. 
