FALCONID^ — DIURNAL RAPTORES. 



429 



3. ^salon. Sizs small (wing novor more than 9 inches). Sexes very different in 

 adult plumage, the young of both sexes resembling the adult female. 



. Basal joint of toes covered with transverse scutellie. Tarsus longer than middle 

 too. 



4. Tinnunonlns. Size small (wing never more than 8 inches in the American 

 sproies). Sexes very different at all ages, but not differing according to age.* 

 Large transverse scutelliB of feet interrupted at lower extremity of tarsus and 

 extreme base of toes. Tarsus much longer than middle toe. Bill small, the core 

 on the top less than one fourth the culmen. 



5. Bhynohofaloo. Size medium (wing more than 9 inches). Sexes alike in color, 

 and young not essentially different from adults. Large soutellae of feet unin- 

 terrupted at base of toes. Tarsus but little longer than middle toe. Bill very 

 robust, the cere on top about one third the culmen. (Tropical, north to Texas.) 



Subgenus Hierofaico Cuvter. 



Bierofalco Cnv. Beg. An. 1817. 312. Type, Falco candicans GMEL..=ii'. islandus Brunn. 

 Oennaia Kaup, Isis, 1847, 69. Type, Falco jugger Geat. 



Synopsis of North American Species. 



. r. gyrfalco. Feathering of the tarsus extending around on to the posterior face, 

 where the narrow naked strip is nearly or quite concealed. Male. Wing, 1.3.00-1.5.80; 

 tail, 7.50-lO.UO. Female. Wing, 15.75-17.00; tail, 9.5O-11.50. Colors extremely variable, 

 the extremes being bluish or brownish gray barred or striped with dusky on the 

 upper parts, and uniform dark sooty slate, with tew or no light markings. 



. F. mexicanua. Feathering of the tarsus confined almost wholly to the anterior face, 

 the posterior face entirely naked. Male. Wing. 11.80-13.50; tail, 6.40-8.00. Female. 

 Wing, 13.25-14.30; tail. 8.OO-9.00. Adult male. Above light brown, barred anteriorly 

 with pale fulvous and posteriorly with pale bluLsh gray; top of head grayish brown, 

 streaked with dusky. Adult female. Above brown, without distinct bars, but 

 feathers bordered with paler rusty brown. Young. Above brown, feathers distinctly 

 margined with light rusty; beneath creamy white, the axillars and broken flank- 

 patch dusky brown; chest, etc., streaked with dark brown. 



Falco mexicanus Schleg. 



PRAIKIE FALCON. 

 Popular synonym. American Lanner Falcon. 



Falco mexicanus "LiCHT." ScHLEG. Abh. Geb. Zool. 1841, 15.— CouEi3. Key. 1872, 213; 

 Check List, 1874, No. 342; 2d ed. 1882. No. 502. 

 Falco polyagrus (part) Cass. Proc. Phil. Acad. vi. 1854. 450; Illustr. B. Cal. etc. 1853. 88, 



pi. 16 (light flg.) ; in Baird's B. N. Am. 1858. 12.— Baikd, Cat. N. Am. B. 1859, No. 10. 

 Falco lanarius var. polyagrus B. B. & R. Hist. N. Am. B. iii, 1874. 123. 

 Hierofaico mexicanus polyagrus KiDow. Nom. N. Am. B. 1881. No. 412. 

 Hab. Western United States and table-lands of Mexico; north to Washington Ter- 

 ritory and Dakota, east to IlUnois (prairie districts), Indian Territory, etc. 



• In the European Kestril IF. tinnunculus Linn.) and its Old World allies, the young 

 male is said to resemble the adult female in coloration. 



