Bird populations were censused by the spot-mapping method in a Quercus mongolica forest at Ashoro, eastern Hokkaido, during the breeding seasons of 1984 and 1985. During the study period 40 bird species were recorded, 29 of which occupied territories within the study area. The most abundant species included Anthus hodgsoni, Phylloscopus occipitalis, Ficedula narcissina, Muscicapa latirostris, Parus palustris, Parus ater, Parus major, Sitta europaea, and Passer rutilans. The results were discussed in comparison with bird community studies conducted in other types of deciduous broad-leaved forests in Hokkaido.