2021 Volume 70 Issue 2 Pages 161-174
In Japan, the wild population of the Oriental White Storks Ciconia boyciana is increasing owing to reintroduction projects. In order to support the continuous population increase, we collected behavioural data on a breeding pair that had not received supplementary food for 20 months, focusing on their territory and home range sizes. We analyzed these areas by kernel density estimation for each sex, and determined the most plausible range of each territory by recording the locations where aggressive interactions occurred with other storks. Our results indicated that the territory of the study pair, within their home range, was a 40% kernel density of the overlap area (65.82 hectares) between pair members. Territorial defense consisted of direct fights (pecking and driving away) predominantly carried out by the male, and indirect fights (bill-clattering) performed equally by both sexes. The pair's home range sizes changed synchronously between the non-breeding period during 2017–2018 and the nest-building and copulation phase in 2019 preceding egg-laying. Different patterns of change for the male and female were found during the incubation period in 2019 and the early chick-rearing stage in 2019; in particular, the male stayed within the territory whereas the female frequently occurred outside the territory. These results suggest that the necessary conservation and management areas differ for male and female breeding Oriental White Storks.
