428 
NORTHERN THREE-TOED WOODPECKER; 
primaries being somewhat duller ; these are regularly marked 
on both webs with square white spots, larger on the inner 
webs, and as they approach the base ; the secondaries are 
merely spotted on the inner vane, the spots taking the ap- 
pearance of bands ; the tips of all the quills are unspotted, the 
lower wing-coverts are waved with black and white, similar to 
the flanks ,* the tail is four inches long, of the shape usual in 
the woodpeckers, and composed of twelve feathers, of which 
the four middle, longest, and very robust and acute, are plain 
deep black, the next on each side is also very acute, and black 
at base, cream white at the point, obliquely and irregular- 
ly tipped with black ; the two next to these are cream white 
to the tip, banded with black on the inner vane at base, the 
more exterior being much purer white and somewhat rounded ; 
the exterior of all is very short and rounded, and banded 
throughout with black and pure white : the tarsus is seven- 
eighths of an inch long, feathered in front for nearly half its 
length, and, with the toes and nails, dark plumbeous ; the nails 
are much curved and acute, the hind one being the largest. 
The above is a minute description of our finest male speci- 
men, with which all those we have examined coincide more or 
less. By comparing, however, this description with the de- 
tailed ones found in some works, we must conclude that the 
species is subject to variations in size and plumage, which, 
according to the erroneous impression given by authors, could 
not be satisfactorily accounted for by difference of sex, age, 
or locality : thus in some specimens the cervix is described 
white, or partly whitish, instead of being wholly black ,* the 
back is also said to be waved with white ; which is indeed the 
case, and with the cervix also, but only in young birds. There 
is a circumstance, however, that could not be explained by 
supposing a difference of age, for while some specimens are 
seen with no appearance of white or yellow on the crown, but 
having that part, as well as the body, rich shining black, others 
with a good deal of lemon yellow on that part, are of a duller 
black, much varied with white. As in other doubtful and in- 
