2025 Volume 74 Issue 2 Pages 223-241
Black Woodpecker Dryocopus martius is designated as an endangered species in Japan, where it plays an important role in forest ecosystems. Unlike other woodpecker species in Japan, Black Woodpecker excavates cavities in living-tree trunks to obtain food resources during winter. Understanding their foraging habitat preferences during winter, especially in relation to how limited food availability may negatively affect their survival, is important for promoting conservation efforts. We searched for living trees with signs of excavation by Black Woodpecker in the mountainous regions of Sapporo City, Hokkaido,to analyze winter foraging trees and habitats. We found that they preferred to forage on large-diameter trees in lowland forests, especially in habitats with many conifer snags and a high ratio of coniferous to deciduous trees. They also significantly preferred to forage on two tree species: Japanese Larch Larix kaempferi and White Birch Betula platyphylla,.Maximum entropy (MaxEnt) modeling was used to estimate suitable foraging habitat for them in winter. The MaxEnt model indicated that lower altitude, higher proportions of larch forest, gentler slopes, and wetter terrain increased the probability of suitable winter foraging habitat, while north-facing slopes showed a lower probability of suitable foraging habitat compared to other aspects. Our results suggest that Black Woodpecker prefer to forage in lowland forest close to urban areas of Sapporo City during winter. These findings highlight the need to preserve mature forests at low elevations as an important role in conserving suitable winter foraging habitat. Furthermore, identifying suitable winter foraging habitats of Black Woodpecker, which include important structures for biodiversity such as large-diameter trees and snags, may contribute to the efficient zoning of areas with high biodiversity.
