This study aimed to examine and compare the breeding biology of two sympatric woodpecker species, Picus canus and Dendrocopos major , in the midwestern region of South Korea, with the goal of elucidating interspecific differences in breeding strategies among closely related taxa. From 2018 to 2021, a total of 106 breeding nests (57 belonging to P. canus and 49 to D. major ) were identified within forested areas of Seocheon and Gunsan. Data were collected on the species of nest trees and their structural characteristics, alongside breeding parameters such as egg-laying date, clutch size, period of incubation and nestling, and rates of hatching and fledging success. Observations were conducted through external nest monitoring supplemented by internal inspections using an endoscopic camera. Both species primarily selected Paulownia coreana , Prunus sargentii , and Castanea crenata as nesting cavities; however, P. canus preferred nest trees with greater height and diameter at breast height compared to those chosen by D. major . The mean egg-laying date for D. major occurred approximately two weeks earlier than that of P. canus , while clutch size and incubation period were significantly larger and longer, respectively, in P. canus . In contrast, no significant interspecific differences were detected in nestling period or in hatching and fledging success rates. This suggests that a larger clutch size does not necessarily lead to higher breeding success under similar nesting conditions. These results indicate that sympatric woodpecker species may share overlapping nesting resources yet exhibit distinct species-specific differences in nest tree structural selection, and breeding traits. This study provides foundational insights into the breeding biology of woodpeckers inhabiting temperate East Asian forests and advances understanding of breeding strategies and coexistence mechanisms among cavity-nesting avian species.
Lee et al. (Thu,) studied this question.