Abstract
Birds of an agricultural land were censused by the line-transect method at the Obihiro University Farm in Obihiro, Tokachi District, Hokkaido from 1976 to 1983. The study area is a mosaic of cultivated fields, pastures, shelterbelts of larch, forest islands of deciduous trees and farm facilities. A total of 76 species of birds was recorded by censuses of 92 times during the study. The number of species was 19 to 23 from January to March, then increased to 39 to 40 by recruitment of summer visitors. After August it decreased as summer visitors left the study area. Seasonal change in the number of birds for all species was similar to that of the number of species except in September and October, in which more birds of Passer montanus and Carduelis sinica were counted than in other months. In breeding season main species included Passer montanus around farm facilities, Emberiza spodocephala and Anthus hodgsoni at forest island, Saxicola torquata and Emberiza aureola in pasture, and so on. During winter Passer montanus and parid birds dominated. Avifauna at agricultural land was characterized by mixed one of both forest and grassland birds.
