ORNITHOLOGICAL EXPLORATIONS. * 209 



the islands, but it would not be surprising to learn, in a not distant fut- 

 ure, that it bad become a breeding bird. The Arvicolw were introduced 

 only a few years ago, but are now so extremely abundant that they 

 might afford food for a numerous colony of birds of prey. 



The specimen in question shows no appreciable difference from birds 

 of Europe, Japan, or Northwestern America. The suspicion of Tacza- 

 uowski, that the Kamtschatkan specimen, which presented some pe- 

 culiarities of coloration, might belong to a separate race (Bull. Soc. Zool. 

 France, 1883, p. 330), seems, therefore, not well founded. On the other 

 hand, after comparison, I agree perfectly with Mr. Nelson {I. c), that 

 the Alaskan specimens are indistinguishable from the palsearctie form. 



The specimen, alluded to above, measures as follows : 



" $ " U. S. Xat. Mhs. No. 101194 ; Grebn. No. 65. Bering Island, January, 1884, 



Wing, 430™™; tail-feathers, 243™™; culmen from cere, 25™™ ; commissure, 41™™ ; 

 tarsus, 77™™ ; middle toe without claw, 35™™. 



94. Haliaeetus leucocephalus (Lin.). 



1766.— Falco leucocephalus Lin., Syst. Nat., 12 ed., I, p. 124.— Kittl., Kupfert, I, p. 4 

 {I8'i2).—Aquila I. Pall., Zoogr. Ross. As., I, p. 347 (1826).— Kittl., Denkw., 

 II, p. 278 {1858).— Ealia-tus I. Steph. in Shaw, Gen. Zool., XIII, 2, p. 13 

 (1826).— Dall & Bann.. Tr. Chic. Ac, 1, 1869, p. 272.— Finsch, Abh. Brem., 

 Ver., Ill, 1872, p. 22.— Dall, Avif. Aleut. IsL, Unal eastw., p. 2 (1873).— M, 

 Avif. Aleut. Isl., west Unal., p. 3 (1874).— Bean, Pr. U. S. Nat. Mus., 1882, 

 p. 162.— Nelson, Cruise Corwin, p. 30 (1883).— Hartlaub, J. f. Orn., 1883, 

 p. 363._Stejneger, Pr. U. S. Nat. Mus., 1883, p. 66.— /d.,Naturen, 1884, 

 p. 8.— Palmen, Swed. Cat. Loud. Fish. Exh., p. 203 (1883).— Saunders, Ibis, 

 1883, p. 350.— Turner, Auk, 1885, p. 157. 



1826.— Aquila pelagica Pall., Zoogr. Ross. As., I, p. 143 {part). 



The Bald Eagle inhabiting Bering Island is here recorded under the 

 name of H. leucoctphalus, though I am, by no means, satisfied as to the 

 propriety of so doing, since all the specimens which 1 have obtained and 

 those which I have had the opportunity of examining — altogether eleven 

 specimens — indicate certain diflerences from typical leucocephalus, which 

 make me believe that we will have to recognize ultimately a northwestern 

 race of this bird, somewhat corresponding to the northwestern race of 

 the gray sea eagle, which Faber has designated as H. albicilla borealis. I 

 do not deem the material quite sufficient, however, to decide the question, 

 for, although twenty-four specimens are not a despisable number of so 

 large a bird, the fact that the sexing in many cases is evidently un- 

 reliable, while in others no delermina,tion of the sex has been attempted 

 by the collector, makes it less valuable and conclusive than would other- 

 wise have been the case. It may therefore be considered best only 

 15861 Bull. 29 14 



