Abstract
Great Spotted Woodpeckers Dendrocopos major were studied in fragmented forests during the 1999-2002 breeding seasons. The 40 km2 study area is in agricultural land in southern Obihiro City (42°46'N, 143°05'E) isolated by about 5 km from an area of continuous forest. The number of nests were 30, 12, 26 and 17, and, of the first three years, 18, 8 and 9 were successful and 2, 3 and 2 failed. Over the four year study 26 male and 25 female breeding birds were individually identified, but more than half of them disappeared before the following breeding season. Range of annual survival rates of both sexes was c. 30% to c. 60%. The maximum distance between nests used by the same individual in two consecutive years was 1,170 m, while in non consecutive years it was 4,720 m. Fragmented forests are presumed to contribute to the maintenance of the population.
