Apparent survival and dispersal in a White-throated Dipper (Cinclus cinclus) population from northern Iberia

Abstract

River systems are some of the habitats most drastically affected by climate change. Consequently, many riparian species are amongst the most threatened living organisms worldwide, making riparian areas a conservation priority. Demographic analyses destined to improve our comprehension of the population dynamics of riparian species are crucial in this context. The present work analyses the spatio-temporal demographic dynamics of a presumably well-preserved White-throated Dipper (Cinclus cinclus) population from northern Spain. Using multistate models where we considered the effects of factors such as mean water flow in winter, age, sex, hydrographical basin of origin and hatching date, we found that the population had a constant annual dispersal rate (ψ = 0.038; 95% CI: 0.022–0.065). The mean apparent survival of Dippers from first-order clutches was 0.18 (95% CI: 0.12–0.22), whereas for those hatched in second-order clutches was 0.07 (95% CI: 0.03–0.15). The mean annual apparent survival for adults was 0.64 (95% CI: 0.56–0.70). Although apparent survival varied from year to year, we found no effect of the average winter flow on this parameter. Recapture probability (p) varied among basins, probably reflecting a heterogeneous sampling effort. In conclusion, using multistate models were found that Dippers from three adjacent river basins in northern Spain had a very short-range natal dispersal rate, and a breeding dispersal close to zero, a trait that could be different from findings in other zones of Spain, where dispersal rates seem to be much higher.