Using Long-Term Constant-Effort Banding Data to Monitor Population Trends of Migratory Birds: A 33-Year Assessment of Adjacent Coastal Stations

摘要

Abstract. One technique for monitoring population trends of many species of migratory songbirds is to assess changes in population indices at constant-effort mist-netting stations located at sites of migration stopover. However, few studies have attempted to validate this approach. We compared long-term (1969–2001) population trends based on annual variation in capture rates at two banding stations located 30 km apart in southern Rhode Island, with one on the mainland, the other on an offshore island. Of 24 species with sufficient sample sizes, 21 species exhibited a significant linear decline at one or both stations. There was a high degree of conformity in trend-slope directions observed at each station. Annual fluctuations and trend magnitude conformed less well, although there was more concordance for nine transient species that do not breed in southern New England. At both stations trends were similar to those at a migration-monitoring station ～95 km away in coastal Massachusetts. The trends at this ...