.--Breeding of the Black Guillemot, Cepphus grylle, along the arctic coast of Alaska has been suspected by several authorities (A.M. Bailey, Colorado Mus. Nat. Hist., Pop. Ser., .no. 8: 257, 1948; I. N. Gabrielson and F. C. Lincoln, The birds o! Alaska, Harrisburg, Pennsylva- nia, Stackpole Co., and Washington, D.C., Wildlife Mgmt. Inst., 1959, see p. 483; R. W. Storer, Univ. Cali/ornia Publs. Zool., 52: 200, 1952), but has not been confirmed by actual observation. Specimens of C. g. mandtii in breeding plumage have been col- lected near Point Barrow in summer (MVZ 134733, taken 23 June), and immature birds are occasionally seen in August. Native hunters of the Eskimo village of Barrow report that occasional birds of this species are seen in open areas in the sea ice in all months of the year. This is substantiated by winter specimens (MVZ 152785, taken 27 February). In its breeding habitat the Black Guillemot is a bird of rocky cliffs. J. D. Soper (Auk, 57: 17, 1940) states that "an indispensable feature [of the nesting habitat] is the presence of talus slides at the base of cliffs near the sea where the nests are hidden away among the boulders. This imposes a highly restraining influence on general dis- tribution." The established breeding range of the C. g. mandtii extends from the northeast coast of Greenland east to the Siberian arctic coast (Storer, 1952: p. 200 and fig. 17; M.D. F. Udvardy, p. 98 in Pacific basin biogeography (J. L. Gressitt, Ed.), Honolulu, Bishop Mus. Press, 1963). L. G. Swartz (p. 615 in Environment o! the Cape Thompson region, Alaska IN. J. Wilimovsky and J. N. Wolfe, eds.], Oak Ridge, Tennessee, USAEC Div. Tech. Info. Ext.) observed Black Guillemots breeding at Cape Thompson on the northwest Alaskan coast, where rocky cliffs of the type Soper describes are common. No such cliffs exist along the northern Alaskan coast, and the conditions under which we found the species breeding there are most novel. On 15 August 1966 two Eskimo seal hunters, Joseph Ahgeak and Merle Solomon, reported finding the nest of a small, black sea-bird near the tip of Point Barrow, the northernmost extremity of Alaska. On 17 August we visited the nest and identified the birds as Black Guillemots. (The similar Pigeon Guillemot, Cepphus columba, has not been recorded in extreme northern Alaska.) The nest was in a 55-gallon oil drum, open at one end and partly submerged in the gravel of the Point. The drum was ap- proximately 200 m from the end of the Point and 40 m from the shallow water (maxi- mum depth, 2 m) of Elson Lagoon. A single egg rested directly on the gravel in the back of the drum. The incubating bird left the nest as we approached and flew to the lagoon, where it was joined by another adult, presumably its mate. Both birds re- mained in the water near shore while we were there. At the same time two other adults in breeding plumage were seen approximately 200 m away. The breeding status of these birds is unknown. Before our next visit to the nest on 3 September, a young Eskimo shot the two nest- ing adults (although the natives do not use alcids as food). We found the egg par- tially hatched, so we collected the chick and preserved it in alcohol (MVZ 3537). On 22 August a second nest was reported to us. It was on gravel under a ruined building near Elson Lagoon, 4 km south of the previous nest. This nest contained two juveniles. We left the area shortly thereafter, and have no more information on this nest. Such use of artificial nesting cavities apparently permits limited breeding in this area beyond the known normal breeding range of the species. This suggests that dis- tribution of the Black Guillemot is limited by the lack of suitable nesting sites. These observations were incidental to a study of the ecology of certain vertebrates supported by a grant from the Arctic Institute of North America to Dr. Frank A. Pitelka. Field support was provided by the Arctic Research Laboratory.--S. F. M^c- LE^N, JR., and N. A.M. VERBE:, Museum o] Vertebrate Zoology, University o] Cai- ]ornia, Berkeley, Cali]ornia.