Abstract
Observations were made of breeding Black Woodpeckers Dryocopus martius at two sites in Hokkaido; a conifer forest in Shikaoi (43°18'N, 143°7'E, 810m alt.) in 1987 and a deciduous broad-leaved forest in Chitose (42°45'N, 141°17'E, 260m alt.) in 1988. In 1987, eggs were laid between May 11-13, hatching on May 27 or 28. Three young fledged on June 29 1987, and on June 21 1988 respectively. Based on breeding records from the present study, and other sources in Hokkaido, young fledged in mid-June in southeastern areas, and in late June in other areas. The combined sex ratio for 26 broods was 1:1. Both the male and female incubated eggs and brooded nestlings during the day, up until the first week of the nestling period. Only the male incubated eggs and brooded nestlings at night during the corresponding period. Frequency of feeding increased from 10 times per day in the early nestling period, to 20 times per day in the middle of the nestling period. Feeding then began to decrease 4 to 5 days before fledging. Frequency of carrying faeces also began to decrese 4 to 5 days before fledging. Both males and females perched on trees near the nesting tree when flying to and from the nest. Frequency of perching after feeding began to increase before fledging. Freguency of drumming also increased just before fledging. Diet consisted mostly of ants, Formica sanguinea, Lasius niger, Camponotus obscuripes and C. herculeanus sachalinensis.
