FALCONID.E — THE FALCONS. 213 



strongly curved, very acute. Wings very long, the third or fourth quills longe.st ; first 

 sliorter than the sixth ; outer three to five with inner webs sinuated. Tail very long, 

 about two thirds the wing; rounded. 



The relationships of this well-marked genus are, to Accipiter on the one 

 hand, and Ulan us on the other; nearest the former, though it is not very in- 

 timately allied to either. I cannot admit the subgenera proposed by various 

 authors (see synonomy above), as I consider the characters upon ■which they 

 are based to be merely of specific importance, scarcely two species being 

 exactly alike in the minute details of their form. 



The species are quite numerous, numbering about twenty, of which only 

 about four (including the climatic sub-species, or geographical races) are 

 American. North America possesses but one (C. hudsonius, Linn.), and this, 

 with the C. cincre^is, Vieill., of South America, I consider to be a geo- 

 graphical race of C. cyanms of Europe. 



The birds of this genus frequent open, generally marshy, localities, where 

 they course over the meadows, moors, or marshes, with a steady, gliding 

 flight, seldom Happing, in pursuit of their food, which consists mainly of 

 mice, small birds, and reptiles. Their assault upon the latter is sudden and 

 determined, like the " Swift Hawks," or the species of Acciintcr. 



In the following synopsis, I include only the three forms of C. cyanexis, 

 giving the characters of the European race along with those of the two 

 i^erican ones. 



Species and Races. 



C. cyaneus. Wing, 12.50 - 16.00 ; tail, 9.00 - 10.70 ; culmen, .60 - .80 ; 

 tarsus, 2.'t2- 3.25 ; middle toe, 1.10-1.55. Third to fourth quills longest ; 

 first shorter than sixth or seventh ; outer four with inner webs sinuated. 

 Adult male} Above pearly-ash, with a bluish cast in some parts ; breast 

 similar ; beneath white, with or without rufous markings. Adtdt female. 

 Above brown, variegated with ochraceous on the scapulars and wing- 

 coverts ; beneath yellowish- white or pale ochraceous, with a few longitudi- 

 nal stripes of brown. Young (of both sexes). Like the adult female, but 

 darker brown above, the spotting deeper ochraceous, or rufous ; beneath 

 pale rufous, the stripes less distinct. 



Tail and secondaries without a subterminal band of dusky ; lower 

 parts without any markings. 



Wing, 12.50 - 1.5.00 ; tail, 9.00 - 10.70 ; culmen, .60 -.75: tar.'^us, 

 2.70-2.85; middle toe, 1.10- 1.35. Hah. Europe . var. cyaneus? 



' The females and immature males are hard to distinguish, and from the unsatisfactory charac- 

 ter of the material at my eommand I have not succeeded in finding reliable characters by which 

 these plumages of the tlnee races may be distinguished. Consequently I give only the characters 

 of the adult males, in defining the distinctions between them. 



^ Circus cyaneus, var. cyaneus (Lix.s. ). Falco cyaneus, Linn. S. N. 1766, 126. Circus cya- 

 neus, Le.ss. Man. Om. 1, 105. — Gould, B. Europe, pi. xxxiii. — Bonap. List, 22. — Degl. 

 Om. Eur. I, 74. — Stkickl. Om. Syn. 1, 147. — Gray, Hand List, I, 37, No. 364. Falco 

 pygargus, Linn. S. N. 1766, 126. Circus pygargus, Steph. Zool. XIII, pi. ii, 41. 



Specimens examined. — National Museum, 3 ; Philadelphia Academy, 4 ; New York Museum, 

 1 ; Boston Society, 5. Total, 13. 



