FALCONID.E — THE FALCONS. 



113 



Hab. Greenlanil, and continent of Nortli America, north of Hudson Bay (breeding- in 

 latter region). Of irregular occurrence in winter throughout the cirourapolar regions ; 

 Ui'al Mountains (Evebs.m.a.n) ; Behring"s Strait (Bannistkk). 



LIST OF SPECI.MENS EXAMINED. 



National Museum, 7 ; Boston Societ}', 2 ; Philadelphia Academy, 3 ; New Yorl 

 Museum, 6 ; collection of R. Ridgway, 1. Total, 19. 



Measuremenix. 



V;ir. islaiKlicua, Sabise. 



ICELAND GERFALCON. 



Accipiier fako islandicus, Briss. Orn. I, 336, 1763. Falco islnndicus, S.A.B. Linn. Trans. 

 XII, 528, 181S. — Temm. Man. Orn. pt. x ; 17, pt. iii, p. 9 ; Tab. Meth. p. 2, 1836. — 

 Fabeu, Prod. Island. Orn. 1822, p. 2; Isis, 1827, 62. — KiCH. & SwAixs. F. B. A. II, 

 27, 1831. — Hoy, Mag. Nat. Hist. Ser. 1, VI, 107. — Hancock, Ann. Nat. Hist. II, 

 247 ; Rev. Zobl. 1839, 123. — Bonap. Consp. Av. p. 24. — Strickl. Orn. Syn. I, 77, 

 1855. — Cassix, Birds N. Am. 1858, 13. Hicmfalco islandicus. Gray, Gen. B. p. 3 

 (ed. 2, p. 4), 1844 ; Hand List, I, 18, 1869. FaJco candicans islandicus, ScHLEG. Krit. 

 libers, p. 1, 1S44. Falco lanarius, Faber, Isis, 1827, 68. Falco gyrfalco, Keyserlino 

 & Blash-.s, Wirbelth. Eur. p. 135, 1840. 



Sp. Char. Adall (^.Iceland; No. 12, Coll. Geo. N. Lawrence). Ground-color 

 of the plumage dull white, gradually becoming somewhat blui.sh posteriorly, this color 

 especially noticeable on the tail. Whole upper parts crossed with broad transverse 

 bands of dark plumbeous, these bands continuous, and more than twice as wide as 

 the pale ones, except on the upper tail-coverts and tail, where the bands of the two colors 

 are more regularly defined and about equal ; in addition to the transverse bands, the 

 feathers anteriorly have narrow borders of white. Tail with the dark bands twelve in 

 number : the terminal pale band is purer white than the others. The dusky plumbeous 

 prevails on the primaries, and is unvariegated beyond the middle portion ; the anterior 

 half, however, is marked with quadrate ragged spots, of a slightly yellowi.sli-white ; all 

 are margined terminally with purer white. Each feather of the head and neck with a 

 narrow medial streak of dusky, but the general aspect abruptly lighter than the back : the 

 streaks are more condensed along the upper and terminal poi'tion of the ear-coverts. 

 Jugulum and breast with a medial narrow streak on each feather ; abdomen with more 

 elliptical streaks; sides with circidar and cordate spots, and flanks and tibiie with trans- 

 verse spots ; lower tail-coverts with narrow shaft-streaks of dusky. Lining of the wing 

 with sparse narrow streaks of dusk)' ; uudcr surface of primaries with white prevailing, 

 this, however, crossed by narrow bars of dusky, these numbering about si.xteen on the 

 longest. Wing-formula, 2-3-1. Wing, 14.00; tail, 7.80; culmen, 1.00; tarsus, 2.30 ; 

 middle toe, 2.00. 



Juv. (No. 20,344, Iceland). Ground-color of head, neck, and lower parts, white. 

 Upper surface grayish umber-ljrown, becoming paler and more graj'ish on the tail ; each 

 feather above sharply bordered (lioth webs, all round) with dull white, producing a 

 somewhat squamate appearance ; in places, a few obsolete hidden spots of yellowish- 

 white Tail .ishy-drab (feathers somewhat paler along edges), crossed with about eleven 



vol.. III. 15 



