Relationship between communal roosts of Grey Starlings and surrounding environment in urban area

Abstract

The aim of this study is to grasp the distribution of grey starling’s communal roosts formed in urban areas and to clarify the surrounding environmental characteristics preferred by them. First, I investigated the distribution of grey starling’s communal roosts in Japan. I defined the roosts in densely inhabited districts as "urban roost," and grasped their distribution and characteristic trends. Next, I performed a wide-area analysis of the relationship between urban roosts in Osaka and land use around them. Finally, I performed a narrow-area analysis of the relationship between five urban roosts in Osaka and their surrounding spatial components. The majority of the 349 (1950-2019) urban roosts were located on the side of roads, in front of stations of commercial areas, and in the roadside zelkova serrata trees. Additionally, in relation to spatial components, more urban roosts were located in areas with middle-high-rise residential buildings. In addition, it became clear that it is important for grey starlings to be near buildings higher than the roosts as a microscopic spatial component.