MIGRATING BIRDS STOP OVER LONGER THAN USUALLY THOUGHT: REPLY

摘要: The seasonal long-distance movements of migratory birds are punctuated by periods rest and refueling termed stopovers. duration these is an important variable in the biology species. Capture-recapture provides data for estimation stopover many species which individual tracking not feasible. Schaub et al. (2001) proposed a new method analysis such data. This note suggests that leads to erroneous estimates mean duration. Estimation absence mortality mathematically identical life expectancy emigration. Life at birth defined as L p(a) da (1) 0 where survivorship probability surviving least age (a continuous p(0) 1) (Keyfitz 1985, Lotka 1998). Relating this duration, we interpret ''age'' time since arrival, sur-vivorship curve proportion remaining population units after arriving. Cormack-Jolly-Seber (CJS) open model (Cormack 1964, Seber 1982) underlie both note. subject recruitment loss between samples. Stopover durations assumed be short, so may ignored, rate departure given 1 t , time-specific CJS ''survival'' parameter (probability animal will also 1). Because dependent under model, cohort arriving i experiences particular ''survivorship'' designated p (a). In case Manuscript