FALCONIDiR — THE FALCONS. 



113 



Hab. Greenland, and continent of North America, north of Hudson Bay (breedinfj in 

 latter region). Of irregnUir occurrence in winter throughout the cu'cunipolur regions ; 

 Ural Mountains (Eversman) ; Behring's Strait (Bannistkr). 



LIST OF SPECIMKNS KXAMINKB. 



National Museum, 7 ; Boston Society, 2 ; Philadelphia Academy, 3 ; New York 

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



Afeasurementii. 



9 



Wing. 



14.40 - 14.75 

 15.75 - 16.25 



Tail. 



9.70 - . 



10.00-11.00 



Culmen. 



.90- . 

 .98-1.00 



Tarsus. 



2.15-2.45 

 2.20-2.50 



Middle Toe. 



1.95-2.00 

 2.05-2.15 



Specimens. 



3 



6 



Yar. islaiidicus, Sabine. 



ICELAND GERFALCON. 



Accipifcr faico islandicua, Biiiss. Orn. I, 336, 1763. Falco islandicun, Sar. Linn. Trans. 

 XII, 528, 1818. — Temm. Man. Orn. pt. x ; 17, pt. iii, p. 9 ; Tab. Meth. p. 2, 1836. — 

 Fabek, Prod. Island. Orn. 1822, p. 2; Isis, 1827, 62. — Rich. & Swains. F. B. A. II, 

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

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

 18.5.5. — Cassin, Birds N. Am. 1858, 13. Hicrnfalco islandiciui, Gray, Gen. B. p. 3 

 (cd. 2, p. 4), 1844 ; Hand List, I, 18, 1869. Falco candicans idandiciis, ScHLEG. Krit. 

 libers, p. 1, 1844. Falco lanariu-i, Fabek, Isis, 1827, 68. Fuho gyrfalco, Keysehling 

 & Blasiu.s, Wirbelth. Eur. p. 135, 1840. 



Sp. Char. Adult ((J, Iceland; No. 12, Coll. Geo. N. Lawrence). Gronnd-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 

 l)ands of dark plumbeous, these bands continuous, an<l 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 un variegated V)eyond the middle portion ; the anterior 

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

 are margined terminally with purer white. Each feather of tiie 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 portion of the ear-coverts. 

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

 elliptical streaks; sides with circular and cordate spots, and flanks and tibias with trans- 

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

 witli sparse narrow streaks of dusky ; under surface of primaries with white prevailing, 

 this, however, crossed liy narrow bars of dusky, the.se numbering about sixteen on the 

 longest. Wing-formula, 2-3-1. Wing, 14.G0 ; 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 grayi.sh umber-brown, becoming paler and more grayish on the tail ; each 

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

 somewhat squamate appearance ; in places, a few ob.solete hidden spots of yollowi.sh- 

 wliite Tail ashy-drab (feathers somewhat paler along edges), crossed with about eleven 



vol.. III. 1.5 



