210 FALCONlDiE, DIXiENjiL BIIiDS OF PliET. GKN. 151. 



Tlie genera Astvr and Accipiter are perfect illustrations of tins group ; the several 

 other genera usually adopted are not very different. Tliere appear to be about 

 seventy-flA'e species, of most parts of the world. 



9. Lastly, the true falcons are prominently distinguished by the presence of a 

 tooth behind a notch of the upper mandible, in the foregoing birds the tomia being 

 simply lobed or festooned, or merely arched. The falcons are birds of medium and 

 small size (one of them is not larger than some sparrows), but extremely compact 

 and powerful organization, and bold ruthless disposition ; they prey by sudden and 

 violent assault, and exhibit the raptorial nature in its perfection. The wings are 

 strong, long and pointed, the tip formed by the 2d and 3d quills supported nearly 

 to the end by the 1st and 4th ; the tail is generally short and stiff. The tj'pical and 

 principal genus is Falco, of which there are, however, several subdivisions corres- 

 ponding to minor modifications. The Australian leracidea, the East Indian lerax, 

 and the Brazilian Uarpagus, which is doublj'-toothed, are the principal other forms. 

 There are upwards of fifty species of true falcons. 



With many exceptions, in this family the sexes are alike in color, but the female 

 is almost invariably larger than the male. The changes of plumage with age are 

 great, and render the determination of the species perplexing — the more so since 

 purely individual, and somewhat climatic, color-variations, and such special condi- 

 tions as melanism, are very frequent. The modes of nesting are various ; the 

 eggs as a rule are blotched, and not so nearlj* spherical as those of owls. The 

 food is exclusively of an animal nature, though endlessly varied ; the refuse of 

 digestion is ejected in a ball by the mouth. The voice is loud and harsh. As a 

 rule, the birds of prey are not strictly migratorjr, though many of them change 

 their abode with much regularity. Their mode of life necessarily renders them 

 non-gregarious. 



In the following sequence of our genera, the student will observe an attempt to 

 indicate affinities not only in the family itself, but with allied families, by the 

 central position of the typical Falco, the series beginning with the most owl- 

 like form, and ending with the vulturine buzzards. But it is hoped that he will 

 detect the imperfection of the arrangement, and that his studies will soon convince 

 him of the impossibility of expressing natural relationships in anj' linear series. 

 With this hint, the inviting problem is left open to stimulate investigation. 



151. Genus CIRCUS Lacepede. 

 fjp Marsh Harrier. Adult $ pale l)luish-ash, nearly unvaried, vi'bitening 



below and on upper tail coverts; quills blackish toward the end; 16-18; 



wing 14-15 ; tail 8-9 ; ? larger, above dark 

 brown streaked with reddish-brown, below the 

 reverse of this ; tail banded with these colors ; 

 the immature $ is like the 9 , though redder, 

 but ill any plumage the bird is known by its 

 white upper tail coverts, and generic charac- 

 ters : face with rufl's ; wings, tail and tarsi very 

 FKi. iM. Marsh Harrier. ]ong, the latter scuteilate before and behind, 



and twice as long as the middle toe ; nostrils oval, etc. North America, abund- 

 ant. Nests on the ground. Wils., vi, 67, pi. 51, f. 2 ; Nutt., i, 109 ; Aud., 

 i, 105, pi. 26 ; Cass, in Bd, 38 ; Coop., 489. . cyaneus var. hudsonius. 



