Use of serum biochemistry to evaluate nutritional status and health of incubating common eiders (Somateria mollissima) in Finland

During 1997-1999, we collected serum samples from 156 common eider (Somater ia mollissima) females incubating eggs in the Finnish archipelago of the Ba ltic Sea. We used serum chemistry profiles to evaluate metabolic changes in eiders during incubation and to compare the health and nutritional status of birds nesting at a breeding area where the eider population has declined by over 50% during the past decade, with birds nesting at two areas with s table populations. Several changes in serum chemistries were observed durin g incubation, including (1) decreases in serum glucose, total protein, albu min, beta -globulin, and gamma -globulin concentrations and (2) increases i n serum uric acid, creatine kinase, and beta -hydroxybutyrate concentration s. However, these changes were not consistent throughout the 3-yr period, s uggesting differences among years in the rate of carbohydrate, lipid, and p rotein utilization during incubation. The mean serum concentrations of free fatty acids, glycerol, and albumin were lowest and the serum alpha - and g amma -globulin levels were highest in the area where the eider population h as declined, suggesting a role for nutrition and diseases in the population dynamics of Baltic eiders.