474 BIBDS OF ILLINOIS. 



Buteo swainsoni Bonap. 



SWAINSON'S HAWK. 

 Popular synonym. Brown Hawk. 



Buteo vulgarus 8w. & RICH. F. B.- A. ii. 1831, 41, pi. 27 (male ad.). AUD.B. Am. 1,1840, pi. 6. 

 Buteo swainsoni BP. Com p. List, 1838, 3. Cass. in Baird's B. N. Am. 1858, 19; ed. 1860, pi. 



13 (female ad.). BAIED. Cat. N. Am. B. 1859, No. 18. COUES, Key, 1872, 217; Cheek 



List, 1874, No. 354; 2d ed. 1882, No. 523; B. N. W. 1874. 355. B. B. & K. Hist. N. Am. 



B. iii. 1874, 263. BIDGW. Nom. N. Am. B. 1881, No. 442. 

 Buteo montanus NUTT. Man. ed. 1840, i, 112. 

 Buteo bairdii HOT, Proc. Phil. Acad. 1853, 451 (= young). CASS. Illustr. 1855, pi. 41; in 



Baird's B. N. Am. 1858, 21. BAIED, Cat. N. Am. B. 1859, No. 19. 

 Buteo insignatus CASS. Illustr. 1854. 102. 198, pi. 41 (= melanistic phase) ; in Baird's B.N. 



Am. 1858, 23. BAIKD, Cat. N. Am. B. 1859, No. 21. 

 Buteo ozypterus CASS. Proc. Phil. Acad. vii, 1855, 282 (= young); in Baird's B. N. Am. 



1858, 30; ib. ed. I860, pi. 15, flg. 2. BAIKD. Cat. N. Am. B. 1859, No. 28. COUES. Key. 



1872. 218. 

 Buteo swainsoni v&r. oxypterus B. B. & E. Hist. N. Am. B. iii, 1874, 266. 



HAS. Western North America, north to the Yukon and McKenzie River districts, 

 south to Central America (Guatemala and Costa Eica), east to the Mississippi Valley 

 (Illinois, Wisconsin, Arkansas, etc.); occasional visitant further eastward, especially 

 north of the Great Lakes and St. Lawrence. Massachusetts (Brewster). Straggling (?) 

 over South America, as far as Patagonia, Argentine Eepublic, and Masafuera. 



SP. CHAE. Only three outer primaries with inner webs emarginated; third or fourth 

 (usually the third) quill longest; first shorter than the sixth (usually about equal to 

 rarely shorter than the seventh). Wing reaching nearly to the end of the tail; prima- 

 ries exceeding secondaries by about one third the length of the wing. Tail even. Trans- 

 verse scutellae on front of the tarsus, 9-13. Color: tail grayish brown, or grayish, some- 

 times with a hoary cast, usually passing narrowly into whitish at the tip, and crossed by 

 an indefinite number of very indistinct narrow bands of a darker shade. Colors of other 

 portions extremely variable. Adult. Nearly uniform dusky brown above, the frontlet, 

 concealed bases of occipital feathers, and the upper tail-coverts more or less mixed with 

 white; beneath sometimes pure white, with a broad patch of uniform brown or rufous 

 on the breast, and white throat-patch, but from this light extreme the lower parts vary 

 to uniform dusky chocolate or sooty brown, through intermediate shades of ochraceous 

 or rufous upon which ground deeper colored bars are visible 011 portions posterior to 

 the pectoral patch; very rarely the lower parts are irregularly spotted with brown, while 

 the pectoral patch is broken up into similar spotting by the admixture of more or less 

 of white. In the extreme melanistic condition the bird is uniformly blackish brown, 

 with white bars on the crissum. Young. Ochraceous and purplish black, in relative 

 quantities varying according to the individual; the ochraceous forms the ground color, 

 and usually predominates, but is sometimes much less in amount than the black; the 

 tail is the same as in the adult. 



a. Normal phase. 



Adult. Above continuous blackish brown, the feathers usually with somewhat paler 

 borders; outer scapulars and upper tail-coverts very rarely tinged with rufous the latter 

 usually more or less barred with white or ashy; occipital feathers white beneath the sur- 

 face ; primaries plain brownish black, without trace of bars on outer webs. Throat and chin 

 more or less white, usually inform of a sharply defined patch; jugulum and breast brown, 

 generally plain, very rarely spotted with whitish, the tint varying from rufous (male) 

 to the color of the upper parts (female). Other lower parts varying from white to ochra- 

 ceous (rarely almost rufous), generally more or less barred, or spotted transversely, with 



