2013 年 45 巻 1 号 p. 39-45
The Black Woodpecker Dryocopus martius was censused along one to three 2-km transects (a total of 1,036) situated in 920, 5-km quadrats (4.5 km×5 km), in Hokkaido from late April to late July, 1976–2012. Based on census results, records from the literature, and personal records of amateur ornithologists, Black Woodpeckers were recorded over almost all Hokkaido, except the plains. They occurred in 21.0% of quadrats in which censuses or observations were conducted. They were observed mainly in evergreen, mixed and deciduous broad-leaved forests, with occurrence rates (No. of transects of occurrence / No. of transects censused) of 11.8%, 16.6% and 6.2%, respectively, and at altitudes below 950 m.