2016 Volume 12 Pages A47-A54
The winter distribution of the endangered Ryukyu Robin Larvivora komadori was surveyed on eight islands within the southern-most island group of the Ryukyu Archipelago of Japan. The surveys were conducted in the Sakishima Island group, including Miyako-jima, Ishigaki-jima, Taketomi-jima, Kohama-jima, Kuro-shima, Hateruma-jima, Iriomote-jima, and Yonaguni-jima. Survey points were randomly located near suitable habitat, including forests or woodlots, and a playback method using the robin's song was used to enhance detectability. Robins were observed on all the islands that were surveyed, and 364 individuals were observed or heard at 300 out of 853 survey points. The scarcity of the past records of this species may be attributable to its low detectability. The species has limited vocal activity in winter, and its habitat preference for dense shrub vegetation in forested areas makes it difficult to observe visually. The plumage characteristics of the 53 individuals observed visually were consistent with those of the northern subspecies L. k. komadori, which breeds in the Amami and Tokara Islands, at the northern end of the Ryukyu Archipelago. The wintering robins were commonly found in evergreen broad-leaved forests, or in small woodlots around coasts or villages. In view of limited availability of these types of areas as wintering habitat for the robin, various types of forest should be taken into consideration when planning effective conservation measures for this species.
