On the morning of 13 April 1971 while looking at birds in the vicinity of Imperial Dam with Bill Clow and Richard MacIntosh, I found an Olivaceous Cormorant Phalacrocorax olivaceus in breeding plumage. The bird was found among Double-crested Cormorants P. auritus on West Pond, situated about one quarter mile west of Imperial Dam on the California side of the Colorado River. During the two hours we had the bird under observation it was perched on a short snag in the pond with an adult and three immature Double-crested Cormorants. The close proximity of the bird to the Double-crested Cormorants enabled us to make a direct size comparison of the two species.