FALCONIDiE — THE FALCONS. HI 



saker, Schleg. (Gray's Hand List, No. 176), seems, to judge from the descrip- 

 tions and figures which I have seen, to be also merely a form of the same 

 species, but I have seen no specimens of it. 



Falco (Hierofalco) gyrfalco, Linn. 



Var. candicaus, Gmelin. 



WHITE GERFALCON. 



Accipiter falco freti hudsonis. Bins. Oni. I, 356, 1763. A. gyrfalco, Briss. Oni. I, 370, 

 pi. XXX, f. 2, 1763. Falco rusticolus, Fabr. Faun. Green, p. 55, 1780. — Lath. Syn. 

 Supp. I, 15, 1781. F. candicaus, Gmel. Syst. Nat. p. 275, 1788. — Daud. Tr. Orn. 

 II, 101, 1800. — Benick, Isis, 1824, 882. —Schleg. Krit. Ubers. p. 1, 1844.— 

 BoNAP. Eev. Zool. 1850, 484 ; Consp. Av. p. 33. — Cas«u\, Proc. Ac. Nat. Sc. Phil. 

 1855,278; Birds N.Am. 1858, 13. — Strickl. Orn. Syn. I, 77, 1855. — Blasius, 

 Cab. Jour. 1862, 43 (thinks all boreal ones same in Europe and America). — Elliot, 

 Birds N. Am. pi. xii. Hierofalco candicans, Cuv. Reg. An. ed. 1, I, 312, 1817 ; ed. 2, 1, 

 323, 1829. — Less. Man. Orn. I, 80, 1828 ; Tr. Orn. p. 97, pi. xvi, p. 2. — Gray, Hand 

 List I, 18, 1869. Falco islandicm, Lath. Ind. Orn. p. 32, 1790; Syn. I, 71, A, B; 

 Gen. Hist. I, 72, A, 1821. — Steph. Zool. XIII, pt. ii, p. 39, 1826. — Gould, B. Eur. 

 pi. xix. ^ AuD. Birds Am. 1831, pi. ccclxvi. F. bideo j3, Lath. Ind. Orn. p. 24, 1790 ; 

 Gen. Hist. I, 80, A. F. lagop2cs, §, Lath. Ind. Orn. p. 19, 1790 ; Syn. Supp. I, 36 ; 

 Gen. Hist. I, 68, A. F. grcenlandicus, Daud. Tr. Orn. II, 157, 1800. Hierofalco 

 granlandicus, Brehm. Voy. Deutsch, I, 16, 1831. F. gyrfalco, Bonap. List, p. 4, 

 1838. 



Sp. Char.- AduU (9, 18,577, Greenland; Univ. Zool. Mus. Copenhagen). Ground- 

 color entirely pure white; whole upper surface (posterior to the nape) with transverse 

 crescentic bars of dark plumbeous-brown, generally about two on each feather, the first 

 concealed by the feather which overlaps. Primaries crossed at regular intervals with 

 c^uadrate spots of the same tint, these becoming fused toward ends of quills, forming a 

 terminal dusky space of two or three inches in extent ; tips of all the quills narrowly 

 white ; the black bars do not extend quite to the primary coverts, and decrease both in 

 extent and regularity toward the base. Middle tail-feathers crossed with seven or eight 

 imperfect bars of dusky, the shafts of the feathers blackish ; rest of tail immaculate, the 

 shafts pure white. Nape with a very few fine shaft-streaks of dusky. Whole lower sur- 

 face of body and wing utterly immaculate. Wing-formula, 2-3-1. Wing, 10.50; 

 tail, 9.00; culmen, 1.05; tarsus, 2.10-1.35; middle toe, 2.20; inner, 1.50; outer, 1.50; 

 posterior, 1.00. 



(No. 56,152, 9, Greenland; Schliiter Collection.) Head above, occiput, nape, and 

 upper half of ear-coverts, with spai'se shaft-streaks of black, these most numerous on the 

 latter region ; primaries barred to the coverts. Tail entirely crossed by eleven plum- 

 beous bars. Bars above clearer plumbeous. The snowy-white beneath is relieved by a 

 few minute variable flecks of dusky upon the lower part of the abdomen, becoming larger 

 as they approach the sides. Wing-formula, 2-3-1. Wing, 16.70 ; tail, 9.30. 



Juv. transition stage? ( (J, 56,047, " Hoher Norden " ; Schliiter Collection). Markings 

 above quite different from those of the two preceding ; each feather has a large central 

 longitudinal sagittate spot of dusky, leaving only the borders (of the exposed portion) 

 white ; on the primaries the dusky is almost confined to the terminal portion ; the rump 

 and upper tail-coverts have each feathers Avith a medial longitudinal stripe of dusky. The 

 tail is immaculate, but the shafts of the middle feathers are dusky. The neck, breast, ab- 



