94 RiDGWAY 071 the Plumage of Gyrfalcons. 



parts with dark brownish slate largely predominating, the creamy white 

 forming longitudinal stripes on the middle of the breast and abdomen, 

 smaller, irregular spots on the sides of the breast, large, transverse, 

 oblong spots (forming interrupted bands) on the flanks, and regular, 

 sharply defined, transverse bands on the crissum ; anal region nearly 

 uniform dusky. Axillars and lining of the wing dark brownish slate, 

 marked with roundish spots of pale cream-color; under surface of the 

 primaries and tail silvery slate, with indications of bars, in the form of 

 transverse, oblong spots, of mottled pale grayish. Wing, 16.25; tail, 9.25 ; 

 culmen, 1.00; tarsus, 2.50 (bare portion, .90); middle toe, 2.10. 



The Labrador Gyrfalcon represents the darkest phase of the 

 Falco gyrfalco of Linnaeus, or the opposite extreme of coloi'-variation 

 from the white race known as F. candicans, Ginel. It may, in most 

 cases, be readily distinguished from the race of the same species 

 inhabiting the interior districts of British America and the Arctic 

 coast, by the darker and much more uniform colors, with dusky 

 largely prevailing on the lower parts, in both old and young. To 

 the more northern form the name sacer, Forster, unquestionably 

 belongs, every point of Forster's diagnosis applying unmistakably 

 to it, even the yellow irides, since it appears, if we may trust the 

 word of collectors, that the Arctic American Gyrfalcon not unfre- 

 quently does have the eyes yellow ! Forster having applied the 

 name sacer to this species in 1772, it follows that this term cannot 

 be used for the Old World species usually thus designated (Falco 

 sacer, Gmel., S. N. L ii, 1788, 273, based on Le sacre of Brisson 

 and Buffon), for which the, name lanarius, Pall. (Zoog. Rosso-As., I, 

 1831, 330), next in order of date, appears to be the proper appel- 

 lation. 



As to the claims of this Arctic American form to recognition as 

 a definable race, a few words may not be out of place here. In 

 " History of North American Birds," Vol. Ill, p. 117, I stated that 

 the var. sacer, as there restricted, was nearly intermediate in its 

 characters between var. islandicus and var. gyrfalco, some specimens 

 approaching very closely to either form. Previous to this state- 

 ment, however, Professor Newton concluded that specimens from 

 Arctic America sent to him for examination could not be distin- 

 guished from true islandicus. The fact that Mr. Dresser has sub- 

 sequently (P. Z. S., 1875, pp. 114 - 117) insisted on the identity of 

 the same sjjecimens with var. gyrfalco, is a somewhat curious cir- 

 cumstance, and tends in a measure to confirm the opinion which I 

 expressed of the intermediate character of the birds in question. 



