THE ARCTIC THREE-TOED WOODPECKER. 
267 
completed, its usual depth being from twenty to twenty-four inches. It is 
smooth and broad at the bottom, although so narrow at its entrance as to 
appear scarcely sufficient to enable one of the birds to enter it. The eggs 
are from four to six, rather rounded, and pure white. Only one brood is 
raised in the season. The young follow their parents until autumn, when 
they separate and shift for themselves. They do not attain their full 
plumage until the second year. 
The number of these Woodpeckers is greatly increased in the State of 
Maine during winter, by accessions from Nova Scotia, Newfoundland, and 
Labrador, in all Avhich countries I have found the species in summer, but 
where, if I am rightly informed, few remain during severe winters. 
Picus tridactylus, Bonap. Syn.,-p. 46. • 
Northern Tiiree-toed Woodpecker, Picus tridactylus, Bonap. Amur. Orn., vol. ii. 
p. 14. 
Picus (apternus) arcticus, Arctic Three-toed Woodpecker , Swains, and Rich. F. 
Bor. Amer., vol. ii. p. 313. 
Northern Three-toed Woodpecker, Nutt. Man., vol. i. p. 578. 
Three-toed Woodpecker, Picus tridactylus , And. Orn. Biog., vol. ii. p. 198. 
Male, 10*, 16. 
From the northern parts of New York to the Fur Countries, as well as 
along the eastern declivities of the Rocky Mountains. Rather common. 
Partially migratory. 
Adult Male. 
Bill longish, straight, strong, angular, compressed toward the tip, which 
is slightly truncate and cuneate ; upper mandible with the dorsal line straight, 
the ridge distinct, the sloping sides quite flat, the lateral angle or ridge close 
to the edges, which are acute and overlapping : lower mandible with the 
ridge distinct, the sides convex, edges sharp and inflected. Tongue com- 
paratively shorter than that of the Picus villosus , but of the same form, the 
extensile part being vermiform, the tip flat above, convex below, and 
serrated backwards on the thin edges. Nostrils basal, elliptical, covered by 
the feathers. Head rather large, neck short, body robust. Feet very short ; 
tarsus scutellate before and behind ; two toes before, one only behind, which 
is versatile and larger, all scutellate above ; claws strong, extremely com- 
pressed, very acute, and uncinate. 
Plumage blended, glossy, on the back and wings rather com pact. Feathers 
of the top of the head stiff and silky. Wings longish, third and fourth 
quills longest and equal. Tail graduated, of twelve decurved stiff feathers, 
worn to a point, excepting the outermost, wdiich is extremely small. Base 
of the bill covered by recumbent bristly feathers. 
