AN INTEGRATED CAPTURE–RECAPTURE AND STABLE-ISOTOPE APPROACH TO MODELING SOURCES OF POPULATION RESCUE

Abstract

Abstract Populations occupying sink habitats can persist if productive local subpopulations exist, if immigrants rescue the population, or if both processes occur. We tested these hypotheses by combining capture–mark–recapture data and recruit origin assignments obtained from feather stable-isotope values from a local Mallard (Anas platyrhynchos) population breeding near Minnedosa, Manitoba, during 2002–2005. Effects important to population growth rates included female nest location (nest tunnel vs. non-tunnel) and recruitment of yearling females originating locally or from nearby parkland areas rather than from more distant regions. Population growth rates of tunnel-nesting females (mean = 1.21 ± 0.22 [SD], n = 3 years) annually exceeded population stability, primarily because the apparent annual survival rate was consistently >0.75. Population growth rates for non-tunnel females (0.90 ± 0.17, n = 3 years) varied annually in response to recruitment rates of yearling females from Aspen Parkland areas; t...