BUTEO. 233 
borealis, the plumage sometimes 
wholly dusky (except the tail), as in 
the adult. 
Tail of adult always with a black 
subterminal bar, and frequently 
with several, more or less com- 
plete, additional bars. Eggs 2.31 
< 1.80. Hab. Western North 
America, south into Mexico, east 
to Rocky Mountains (casually to 
Tilinois). 
3376. B. borealis calurus 
(Cass). Western Red-tail. 
h*, Tail of adult without any black bars; otherwise, 
much like B. borealis calurus. Hab. Cape St. 
Lucas. 
337c. B. borealis lucasanus Rivew. 
St. Lucas Red-tail. 
J’. Middle toe not more than 1.55; tail of adult (and young) 
grayish brown, sometimes slightly touched with rufous, 
crossed by an indefinite number (but varying from 
about 10 to 13) of narrow bands of dusky, which 
become gradually indistinct and finally obsolete toward 
base. 
Plumage exceedingly variable, but usually a mixture 
of sooty brown and whitish, in variable relative 
quantity ; sometimes entirely dusky (except tail) 
and rarely almost entirely white; length about 
20.00-23.00, wing 15.50-16.60, tail 8.80-10.00, cul- 
men .85-.95, tarsus 3.00-3.50, middle toe 1.40-1.55. 
Hab. Northern portions of eastern hemisphere; 
accidental in Michigan ? 
336. B. buteo (Linn.). European Buzzard. 
d?, Middle toe not decidedly longer than bare portion of tarsus in front; 
length of cere on top greater than depth of bill at anterior edge 
of cere. 
Plumage uniform black, or blackish brown, the feathers pure 
white at bases; tail grayish brown or grayish, more or less 
banded with black, the inner webs, however, chiefly white. 
‘Adult: Tail black, crossed by three broad zones, which are 
ash-gray on outer webs and pure white on inner. Young: 
Tail dark grayish brown (the inner webs partly, sometimes 
entirely, white), crossed by numerous narrow, oblique bands 
of black. Male: Length 18.50-19.60, extent 49.50, wing 
80 
