Records of wintering Japanese Marsh Warbler in Southern Okayama Prefecture, Western Japan

Abstract

I studied the occurrence and habitat characteristics of Japanese Marsh Warblers Locustella pryeri wintering in southern Okayama Prefecture, conducted by seasonal observations from March 2014 to April 2016. I studied three reedbed sites: a former salt farm area called Kinkai, the shore of Kojima Lake, and the mouth of the Kurashiki River. I carried out the study using fixed-point observation with or without a call playback method. Warblers were recorded from late November to mid-April, and also recorded as they sang spontaneously, without making flight displays, from late March to Mid-April. Without flight displays, the birds were considered to be present as wintering and not as breeding birds. During the 33 total survey events between late March 2014 to mid-April 2016, 17 surveys resulted in positive detections of the species, and each detection ranged from one to three warblers. The characteristic vegetation of the occupied habitat was reedbed with an undergrowth such as sedge. The reed height was 1.9 to 2.2m, and the density of reeds was 48 to 58 stalks /m2. This study suggests that southern Okayama Prefecture has possibly been used regularly as a wintering site by Japanese Marsh Warblers.