Observations were made of breeding Black Woodpeckers
Dryocopus martius in a mature Todo-fir
Abies sachalinensis stand in Hakodate, southern Hokkaido from 1977 to 1989. For 7 broods, the mean number of young was 3.3, ranging, from 2 to 4 young. The combined sex ratio from 7 broods was 1:1. Young fledged between mid-June and late June. There was no significant relationship between dates of fledging and mean temperature during breeding season. All four nests examined were excavated in live Todo-fir. One of the trees was used up to the breeding season in 1981, and had fallen by May of this year. The other three nest cavities were excavated in 1982, 1983 and 1985 respectively. Three nest trees were located 30 to 40m apart. Diameter at breast height of the nest trees ranged from 46 to 51cm. Nest height ranged from 4.0 to 5.9m above the ground. Entrance diameter inside was 90 to 110mm vertically and 70 to 90mm horizontally. Depth from the bottom of the entrance hole to the bottom of the cavity ranged from 310 to 360mm and the cavity diameter from 200 to 270mm. At the nest site, tree density was 594 trees/ha and basal area (the cross section area of tree trunks at breast height) was 55.7m
2/ha. Based on fecal droppings collected from the nest cavity after the young fledged, the main foods were ants in the later nestling stage.
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