96 Trans. Acad. Sci. of St. Louis. 



prairie east of that town, where it is occasionally seen in winter. 

 A bird answering the description was observed for several days 

 (November 21-23, 1905) on the grounds of the Horse Shoe Lake 

 club in St. Charles Co., and one taken in spring near Billings, 

 Christian Co., is in Mr. Kastendieck's collection. Considering 

 that the Krider's Hawk is only a subspecies of the Plains, a 

 geographical race known to intergrade with the typical eastern 

 form, it seems plausible that Missouri lies in the belt of inter- 

 gradation inhabited or visited by the intermediates. 



337b. BuTEO BOREALis CALURUS (Cass.). Western Red-tail. 



Buteo calurus. Buteo montanus. Black Red-tail. 



Geog. Dist. — Western North America from Mexico to Sitka; 

 east to eastern British Columbia, central Montana, Wyoming and 

 Colorado; in migration to Ontario, Wisconsin, northern Illinois, 

 Nebraska, Kansas and Missouri. 



This more or less darker-colored western race, the light ex- 

 treme of which is said to be scarcely distinguishable from true 

 horealis, is probably not a very rare transient and winter visi- 

 tant in Missouri, especially in the west. Two specimens taken 

 within one week in the fall of 1888 near Billings, by Mr. J, D. 

 Kastendieck, show distinctly the rufous bars on the tibiae, one 

 of the characteristics of the subspecies, said by some authors to 

 constitute even in the young a persistent feature, in which it 

 differs from the almost or quite immaculate white of the young 

 eastern Red-tail. Mr. Chas. K. Worthen writes that he has 

 taken this subspecies repeatedly near Warsaw during the breed- 

 ing season. 



337d. Buteo borealis harlani (Aud.). Harlan's Hawk. 



Falco harlani. Black Warrior. 



Geog. Dist. — Gulf States and lower Mississippi Valley; north 

 to Illinois, Missouri, Kansas, casually to eastern Nebraska, Indi- 

 ana, Minnesota and Pennsylvania. 



Probably a regular summer resident in southeastern Missouri, 

 as it has been observed repeatedly in May in different years in 

 Dunklin and Pemiscot counties. A specimen in the collection 

 of Mr. John D. Kastendieck was shot four miles south of Bil- 

 lings, Christian Co., about the middle of November, 1905. A 

 fine adult male was taken on the Mississippi near Warsaw, 111., 

 opposite the northeastern corner of Missouri, in March, 1879, 



