Monitoring Avian Productivity and Survivorship (Maps): A Sharp, Rather than Blunt, Tool for Monitoring and Assessing Landbird Populations

摘要: Information on avian population trends derived from survey data traditionally has been the major tool used to monitor large-scale, long-term changes in populations, and assess both habitat quality responses of birds management practices natural human-caused environmental changes. Data alone, however, cannot provide critical information needed test competing hypotheses regarding causes observed changes, or even determine stage(s) life cycle at which are taking place. Moreover, density may not correlate well with either productivity survivorship, thus, inaccurately response populations Because many landbird species (particularly neotropical migrants) declining (Robbins et al. 1989), because Earth’s biosphere its facing a growing number global threats ever increasing severity (Brown 1991), an additional for accurately assessing survivorship is critically needed. The Monitoring Avian Productivity Survivorship (MAPS) program designed fill this need. It cooperative effort among North American bird banders that utilizes constant-effort mist netting banding during breeding season continent-wide network stations. For target species, MAPS provides annual, regional indices post-fledging proportion young captured, estimates adult recruitment into size capture-recapture birds. was established 1989 1990 when 17 38 stations, respectively, were operated across continent. Post-fledging 1990, as determined by decreased significantly (P< 0.02) average 32.8% 10 stations years. measure previously shown be highest years relatively “average” weather conditions decrease markedly extreme (DeSante Geupel 1987), year continent (and temperature record), it suggested these representative