The effectiveness of point counts and route censuses in quantifying abundance and richness in bird species was analyzed for data collected at 13 woodland sites during four periods, including wintering seasons from late December 2005 to February 2006, and late December 2007 to February 2008, and breeding seasons from mid-May to mid-June 2006 and 2007. The number of species detected by point count was more than that of route census both during winter and breeding seasons. Moreover, species detection rate during point counts was higher, with shorter survey time, than the detection rate of route censuses. Although there were significant positive relationships in the maximum number of individuals for each species detected using point counts and route censuses in both seasons, the abundance of each species was difficult to compare between point counts and route censuses in winter. Since the sum of the maximum number of individuals recorded at each survey location during point counts was highly correlated with the maximum number of individuals recorded by route censuses during the breeding season, the relative abundance of each species could be compared with each other when using either method. Considering the higher species detection rate of the point count method, the higher total number of detected species, and the similarity of abundance data between the methods, the point count is recommended as the preferred survey method for monitoring population trends when comparing relative abundances of bird species.
2009 by Japan Bird Research Association