2023 年 22 巻 2 号 p. 161-168
Japanese Night Heron Gorsachius goisagi has recently been down-listed in status from Endangered to Vulnerable by BirdLife International due to the presence of a likely larger population than previously considered. However, there is still relatively little known about the ecology and current population status of this rare, elusive, and solitary species. In this study, we used infrared cameras to study its behaviour. We installed cameras at 120 locations on the forest floor of Awaji Island, Hyogo Prefecture, Japan, over approximately one year. Japanese Night Heron was recorded at 15 locations (132 video files of 25 independent events). All records except one were obtained during the daytime, and all involved herons walking on the forest floor where they were searching for potential prey items (most likely earthworms). Both adult and recently fledged juvenile herons were recorded, providing direct evidence that the species breeds on Awaji Island. Additionally, a zero-inflated Poisson GLMM analysis showed that Japanese Night Heron may not prefer evergreen coniferous plantations. Our results not only indicate that the species forages diurnally, contrary to its common name, but also sheds light on the importance of maintaining forests and foraging ground environments for the conservation of this species.