The effectiveness of point counts in quantifying abundance and richness in bird species was analyzed for data collected at 10 grasslands sites during three periods, including a breeding season from mid-May to mid-July 2007, and two wintering seasons from late December 2007 to February 2008, and late December 2008 to February 2009. There was no significant difference between the two methods. The point count method tended to have a slightly better detection rate than that of route census both during winter and breeding seasons. 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, on the other hand, was difficult to compare between point counts and route censuses. 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, 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, 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