Evaluating point count efficiency relative to territory mapping in cropland birds

Abstract

Species richness, composition, and abundance of farmland birds were compared between point counts (50-m, 100-m, and 150-m radius half circles) and territory mapping on three 40-ha plots in Québec, Canada. Point counts of smaller radii tended to have larger density estimates than counts of larger radii. Territory mapping detected 10 species more than 150-m radius point counts. Territory mapping at 150-m radius detected more birds per species than point counts; relative abundances, however, were similar. Bird density is probably optimally estimated with a 100-m radius point count. After four visits, more than 80 percent of species and birds from 7 visits had been detected by 150-m radius point counts. Our modified point count method appears to be accurate enough to reflect the farmland avifauna characterized by more labor-intensive methods such as territory mapping.

Parent Publication

• Monitoring bird populations by point counts

Citation

Cyr, A.; Lepage, D.; Freemark, K. 1995. Evaluating point count efficiency relative to territory mapping in cropland birds. In: Ralph, C. John; Sauer, John R.; Droege, Sam, technical editors. 1995. Monitoring bird populations by point counts. Gen. Tech. Rep. PSW-GTR-149. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: p. 63-68