Feeder counts as indicators of spatial and temporal variation in winter abundance of resident birds

摘要

Project FeederWatch (PFW) is a North American-wide volunteer program that has compiled weekly observations of birds at feeders throughout each winter since 1987- 1988. Three population indices are calculated for each bird species: percent of feeders vis- ited, group size (number observed per visit), and mean abundance per feeder over the entire season. For nine resident species in the northeastern United States, we tested whether PFW indices reflect spatial and temporal patterns of abundance similasr to those derived from the Breeding Bird Survey (BBS).