Stable isotopes in a southern European crossbill population indicate restricted movement between regions with different pine species

摘要: The adaptation of irruptive birds to breed where they find abundant food allows them be highly mobile and ubiquitous opens a debate on the ecological evolutionary impact this behavior. Using δ2H analyses, our aim here was test whether density fluctuation in southern European crossbill population is caused by movements northern crossbills or from nearby. Sampling carried out western Pyrenees during four consecutive breeding seasons (2009–2012). During these years, 2009 year with much higher number captures per day coincided an invasion Europe. Only two 160 showed clear isotopic signatures origin (and both were caught 2009). Moreover, 2009, we recaptured bird ringed Netherlands. Otherwise, found no differences among years significant effect wing length (indicative origin) residency status (long-term recaptures vs. non-recaptures) δ2H. Wing also did not vary years. Therefore, results suggest that annual variation local abundances only due birds, but large part influx reproduction individuals Iberian origin. lack similarity values nearby mountain area same resource (the pine Pinus sylvestris) suggests are primarily between areas type resource. Thus, support recent morphological genetic studies indicate populations within Iberia structured geographically use.