Jan., 1909. Birds of Illinois and Wisconsin — Cdry. 467 



Immature: Upper parts, dark brown, mixed with rufous brown 

 and buff; head, neck, and under parts, pale buff; the head, streaked, 

 and the under parts more or less spotted with dusky. 



Male: Length, about 20; wing, 14.50 to 16; tail, 8 to 9; tarsus, 

 about 2.50. 



Female: Length, 20 to 22; wing, 14.60 to 17; tail, 8.50 to 10; 

 tarsus, 2.50 to 2.85. 



While the various color differences in this Hawk may be confusing, 

 it may be distinguished from other Hawks except the Broad-winged 

 Hawk, which is much smaller, by having only the three outer primaries 

 notched. 



Swainson's Hawk is of casual occurrence during migrations in 

 Illinois, and according to Mr. Nelson it breeds in southern Illinois and 

 probably does so occasionally in other parts of the state. Ridgway 

 states (Orn. of Illinois, p. 475) : "Mr. Nelson found it breeding on Fox 

 Prairie, in Richland Co., during the summer of 1875, and obtained 

 specimens." Mr. Charles K. Worthen has taken it at Warsaw, 111. 

 Mr. Isaac E. Hess informs me that a set of three eggs of this species 

 was taken by Mr. Jessee, at Lynn Grove, near Philo, Champaign Co., 

 111., in 1902. 



In Wisconsin it is not common, but can hardly be called rare, espe- 

 cially during the fall migrations. I have been unable to find any rec- 

 ord of its breeding in Wisconsin, although it probably occasionally 

 does so, as it is a common summer resident in Minnesota and breeds 

 regularly in that state. 



In wooded countries the nest is usually built in large trees, but it 

 also nests on the ground and on cliffs. The nest is a mass of sticks, 

 leaves, and grass or moss, according to locality. The eggs are usually 

 two, rarely three; dull white, sometimes washed (rarely spotted) 

 with brown. They measure about 2.25 x 1.75 inches. 



Subgenus TACHYTRIORCHIS Kaup. 



I6L Buteo platypterus (Vieill.). 

 Broad-winged Hawk. 



Buteo latissimus (Wils.), A. O. U. Check List, 1895, p. 133. 



Distr. : Throughout eastern North America, breeding from Canada 

 to the Gulf states; south in winter to West Indies, Middle America, and 

 South America. 



Adult male and female : Three outer primaries, notched; primaries, 

 dark brown, having the greater portion of the inner webs wh;te, with 



