抄録
Breeding bird communities were investigated monthly from May to July 1991, and in June 1992 and 1993, at the foot of Mt. Toyama in Oku-Nikko, northern Kanto. Two areas were studied. Both contained deciduous broad-leaved forest, one with a mixture of coniferous trees (A) and the other with a larch plantation (B). Thirty-one species were observed, 24 in area A and 21 in area B, with 14 species common to both areas. Total numbers of individuals were always greater in area A than in area B during the study period. The two most abundant species were Parus ater (14.7-17.8% in area A, 8.3-25.0% in area B) and Cettia diphone (12.6-16.7% in area A, 20.1-33.6% in area B). High density of four species of Cuculidae (9.9-12.3%) appeared in area A. Cuculus poliocephalus did not appeared in area B, though its host species, C. diphone was in high density, and Cuculus canorus appeared in both areas, though its host species, such as Lanius bucephalus and Emberiza cioides was in low density.
