234 NORTH AMERICAN BIRDS. 



pure white at bases ; tail grayish brown or grayish, 

 more or less banded with black, the inner webs, how- 

 ever, chiefly white. Adult : Tail black, crossed by 

 three broad zones, which arc 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. 3Iale : Length 18.50-19.60, extent 49.50, wing 

 15.00-15.60, tail 8.50-9.15, culmen .73-.88, tarsus 2.40- 

 2.70, middle toe 1.60-1.65. Female : Length 20.85-21.50, 

 extent 53.10, wing 16.50-17.40, tail 9.00-10.75, culmen 

 .90-1.00, tarsus 2.70-2.80, middle toe 1.80-1.85. Eggs 

 2-4, 2.19 X 1-72, dull white, usually spotted or speckled, 

 chiefly on larger end, with umber-brown. Hab. Mid- 

 dle America, north to southern California, Arizona, 

 Texas, etc., south to northern South America. 



340. B. abbreviatus Cab. Zone-tailed Hawk. 

 d^. Only three outer quills with inner webs distinctly emarginated. 



Tail grayish brown, or brownish gray, sometimes with a hoary 

 tinge, crossed by an indefinite number (about 9 or 10) of nar- 

 row dusky bands, which toward base of tail become gradually 

 indistinct and finally obsolete. Adult male, normal plumage : 

 Above nearly uniform grayish brown; forehead, chin, and 

 throat white, usually abruptly defined and forming a distinct 

 patch ; chest and upper part of breast usually plain rufous 

 or cinuamon (rarely mixed or broken with whitish) ; rest of 

 lower parts buffy whitish, sometimes immaculate, but usually 

 more or less barred or spotted with brownish ; length 19.50- 

 20.00, extent 48.00-50.50, weight lJ-2i pounds, wing 14.40- 

 16.00, tail 8.00-9.00, culmen .80-.90, tarsus 2.30-2.75, middle 

 toe 1.40-1.60. Adult female, normal plumage : Similar to the 

 male, but chest-patch grayish brown instead of rufous, or 

 cinnamon; length 21.00-22.00, extent 50.50-56.00, weight 2\- 

 3i pounds, wing 14.75-17.25, tail 9.00-10.00, culmen .80-.95, 

 tarsus 2.50-2.90, middle toe 1.50-1.65. Melanistic phase, both 

 sexes : Whole plumage uniform sooty brown, the under tail- 

 coverts sometimes spotted or barred with rusty or whitish. 

 (Note. — In diffei*ent individuals may be seen every possible 

 intermediate condition of plumage between this complete 

 melanism and the light-colored normal plumage described 

 above.) Young : Tail as in adult; above blackish brown varied 

 with buffy or ochraceous ; head, neck, and lower parts creamy 

 buff (deeper in younger, paler in older individuals), the lower 

 parts usually more or less spotted with blackish, the head and 

 neck streaked with same, JVest on bushes or low trees, some- 



