256 



CIRCUS CYANEUS. 



ami bent downward to a point at about one half the height of the keel. The marginal in- 

 dentations are large in the ycamg stages, but are always inclosed, becoming smaller in the 

 more adult birds. 



GENUS T. CIRCUS. THE HARRIERS. 



(lEN. Cii. j3i//, not /ony. we.ii airvril. inilh ihn cuUiwj edge qfvpprr mandible slightly lobed. Tarsvs, lony and nearly 

 naked. Tail, lon(j, b,iL is nut ejital in Icnijtk to the winys which arc considerably clonr/ated. Lower portion of face, sur- 

 rounded by a niff. 



Memlier.'; lil' tliis genus not (Hily rcscMuble the owl> in liavini; ;i ruff, or fnci.il di'^k. Uut the ear cavities are large and the 

 plumage is somewhat duwny. Tlie leg is strdtinglj' lung and the tarsus is naked to the heel behind, but isslightly feath- 

 ered in front. Four outer (|uills arc incised on the inner webs. Toe trachea is llaltened throughout. The sterno-trache- 

 alis is short, liaving its origin about '2') from the larynx, and there is a slender Ijronchialis extending over all the half rings, 

 l)ut no other laryngeal muscles. The lympaniform membrane is (vresent and iiltliough there is a thin os transvei-salc, it 

 doGs notsuijport a semilunar memlirane. Tlie walls of tiie tcso]iliagus are thic: this is at fii'st nearly straight, then is dilated 

 into an oblong cro)) near tlic iniddla, after which it is again straight until it opens into a rather small proventriculus with 

 simple, oval glands arranged in a zonular band which measures TOO mcyanevs, from which this and the following dimen- 

 sions were taken. The stomach isof jiiedium size, somewhat globular in firm, with thin but soft walls and is lined with a 

 soft membrane. The fold of tlie duodenuai is long, measuring .'i'50, inclosing a narrow pancreas whicli extends its en- 

 tire length. The cncca are merely represented by slight swellings on either side of the intestine. The spleen is an ellipti- 

 cal body lying directly on the jiroventriculus. Both lobes of the liver are equal in size and are short and thick. The heart 

 is large, bent slightly to tlie right and not very pointed. Sexes, not similar in color. There is but one species within oui 

 limits. 



CIRCUS CYANEUS. 



Marsh Hawk. 



Circus ryaneus Boie, Isi-.; Irt2'2, 549. 



DESCRIPTION. 



Sp. Cii. Form, lung and slender. Size, medium. Sternum, rather stout, witli the marginal indentations varying with 

 age. Tongue, short, not very tlosliy, and about thesame width for nearly its entire length, then abruptly rounded but not 

 bifid. Bill and claws, not long. 



Color. Adult male. Above, inckiling upper wing coverts, siiles of bead, and breast, |iale bluish-ash, becoming rufous 

 on the back of the head and upper neck. Upper tail coverts, white. Wings, brown, edged on the outer webs with ashy 

 and barred with darker. Two middle tail feathers and outer webs of remainder, bluish-ash, and inner webs, rufius, barred 

 across the fjathers with dark-brown. Under portion of tail, silky white. B.:'neath, including under wing and tail coverts 

 and tibia, wliite, spotted with pale reddish. Iris, pale j'ellow. 



Adult female. Above, brown, with t!ie feathers more or less ashy, edged on the bead and neck and spotted on the re- 

 maining portion with rufais. Bt'nsath. including under wing and tail coverts, reddish-white, darkest on tlietibca, with 

 every feather liaving a central spot of reddish-brown, broadest and darkest on the breast, narrower on the neek, smaller, 

 rounder and more decidedly rufous on the posterior portions and tibea: otherwise as in the male. 



Youny male. Similar to the adult female but decidedly darker above, where there is no trace of ashy but there is more 

 ruf lus on the spottings and edgings. Beneath, very dark rufous, not much spotted, often being wholly immaculate on the 

 posterior portion and tiliea. Iris, brown. 



Youny female. Quite similar to the young male butsoraewliat lighter througlKmt, especially below, where the dark- 

 ening of tlie rufous is only seen on the tibia. 



Nesllinys. Are at first covered with a reddish down, then gradually assume the ])lumages last described. Iris, brown. 

 Bill, bluish-black, cere, greenish, feet, yellow, and claws, brown, in all stages. 



OBSERVATIONS. 



There appears to be considerable variation in specimens, some being darker than others and more heavily spotted, but 

 this may be duo to age and sex. Known fro.n all other species by the peculiar ruffabout the face combined witli the white 

 of the upper tail coverts, which i-i noticeable in all stages. Distributed, as a summer resident, throughout Nortli America. 

 Constantly resident in ihcmore southern portions. 



