468 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. IX. 



a few imperfect brown bars, the upper surface of outer webs, entirely 

 without white; upper parts, dark brown, the feathers margined with 

 pale brown and pale rufous brown; tail, dark brown, with two grayish 

 white bars and tipped with whitish; feathers of the under parts heav- 

 ily barred with reddish brown and dull white. 



Immature: Differs from the adult in having more buff about the 

 head; under parts, buffy white, streaked with dark brown; tail, 

 grayish brown, with several rather obscure and irregular bands of 

 dark brown, the tips, whitish. 



The size, combined with having only the three outer primaries 

 notched, will distinguish this species. 



Male: Length, 13.30 to 15.00; wing, 10.00 to u; tail, 6.25 to 7; 

 tarsus, 2.40. 



Female ^Length, 15.50 to 17.50; wing, u to 11.50; tail, about 

 7.50; tarsus, 2.50. 



Broad-winged Hawk (adult). 



The Broad-winged Hawk is common during the migrations and 

 a more or less common summer resident in Illinois and Wisconsin, and 

 breeds in many localities. Nests in trees, usually at a considerable 

 height from the ground. The eggs are three to five, dull white or pale 

 buff, blotched and washed with different shades of brown. They meas- 

 ure about 2.05 x i. 60 inches. Incubation usually begins in May in 

 this latitude. There is a set of three eggs in the Field Museum col- 

 lection taken at Joliet, 111., May 10, 1906. 



