Optimizing the Duration of Point Counts for Monitoring Trends in Bird Populations

摘要

Minute-by-minute analysis of point counts of birds in mixed-conifer forests in the Sierra National Forest, central California, showed that cumulative counts of species and individuals increased in a curvilinear fashion but did not reach asymptotes after 10 minutes of counting. Comparison of the expected number of individuals counted per hour with various combinations of counting time and noncounting times (for record keeping and travel between counting stations) showed that 10-minute counts were most efficient in most cases. Counting longer than 10 minutes is not recommended, because of the increased risk of double counting some individuals.