Breeding Habitats of Dendrocopos major and D. minor in Urban and Rural Areas

Abstract

Characteristics of breeding sites, nest trees and holes of two woodpecker species, Dendrocopos major and D. minor, were investigated in woods and parks in the urban and rural areas of Obihiro, eastern Hokkaido from April to September 1993. In D. major the numbers of nest and birds counted per 30 minutes census increased with area size, but those of D. minor did not vary. Fledging date ranged from June 23 to July 25 with an average of July 2 for D. major and from July 3 to 20 with an average of July 11 for D. minor. Neither D. major nor D. minor showed any preference in vegetation types of nesting site. Of 42 D. major nests including those found out of study areas, 22 were in woods and 20 out of woods. On the other hand, of 9 D. minor nests, 8 were found in woods and only one nest out of woods. Nest tree height, nest height, DBH (diameter at breast height) and DNH (diameter at nest height) were 13.6m, 3.7m, 35.7cm and 28.2cm respectively for D. major, and 8.0m, 3.0m, 11.0cm and 26.6cm respectively for D. minor. D. major used both live and dead trees for nesting, while D. minor used only dead trees with several holes. The minimum DNH was 19cm for D. major and 17cm for D. minor respectively. Values indicating nest sizes and volumes of D. major were larger than those of D. minor. Conditions required for nesting of two Dendrocopos species are 1)minimum area of 1.5ha where they nested, 2)live and dead trees of more than 21 cm in DBH for D. major and 3) dead trees of more than 18cm in DBH for D. minor.