Species temperature index by Japan Breeding Bird Atlas. Species recorded at over 30 sites
From 2016 to 2021, a national survey of birds has been conducted as "Japan Breeding Bird Atlas" We conducted two complete survey courses within each cell of a 20km square mesh (total 2344 courses) placed as a graticule over the map of Japan. Using this data, we determined the average temperature of breeding birds in Japan. The mean temperatures of the distribution areas of various bird species (species temperature index: STI) weighted with number of individuals were calculated. Species recorded at over 30 sites were indicated.