Fledgling production and population trends in Finnish common eiders (Somateria mollissima mollissima) — evidence for density dependence

摘要: We present a 57-year time series of common eider, Somateria mollissima (L., 1758), population from one the core monitoring areas in Baltic Sea, Soderskar bird sanctuary, Gulf Finland. applied permutation tests to inspect relationships between breeding parameters and density. Of studied, only fledging rate (during 34-year period) showed significant negative relationship with size, indicating density dependence. Furthermore, responded strongly growth recruitment. Clutch size duckling (downy young entering water) did not show Thus, losses during brood rearing seem be regulatory factor. The decline at is similar those recorded many other sites around southern coast Compared data more productive sea districts northwestern Europe (Dutch Wadden Sea Scottish Nort...