Abstract
We studied Japanese Marsh Warblers Locustella pryeri wintering on the south coast of Iwate Prefecture, northern Japan from December 2008 to March 2009 and from January to March 2010. The species is listed in the Japanese Avian Red List as an endangered species. The study was carried out by using a playback and capture method. In the reedbeds of the mouth of the Unosumi River, 3–11 or 12 birds were continuously observed on each day throughout the study period. It is, therefore, reasonable to assume that this area was a wintering ground of this species. At each mouth of the Yoshihama and Sakari Rivers, however, only one bird was observed on each day in February and January. We presume that Japanese Marsh Warblers have wintered in the study site since 2002 when paddy fields were abandoned. This record shows that Iwate Prefecture is the northernmost wintering ground of Japanese Marsh Warblers.
