Carlson-Bremer, D., T.M. Norton, F.J. Sanders, B. Winn, M. Spinks, B.A. Glatt, L. Mazzaro, P.G.R. Jodice, T. Chen, E.S. Dierenfeld. 2014. Circulating fat-soluble vitamin concentrations and nutrient composition of aquatic prey eaten by American Oystercatchers in the southeastern United States. Submitted Journal of Avian Medicine and Surgery 28:216-224
The American oystercatcher is currently listed as a species of high concern by the United States Shorebird Conservation Plan. Adequate management of a wildlife population requires intimate knowledge of a species’ diet and nutritional requirements as nutritional status directly impacts overall health and reproduction of individuals and populations. Fat soluble vitamin concentrations of plasma obtained from American oystercatchers and proximate, vitamin and mineral composition of various American oystercatcher prey species were determined as baseline data for assessment of nutritional status. Bird and prey species samples were collected from Cape Romain Region, South Carolina and the Altamaha River Delta Islands where breeding populations appear stable. Circulating vitamin A levels in birds were higher than ranges reported as normal for domestic avian species and vitamin D concentrations were lower than anticipated based on values observed in poultry. Vitamin E levels were within ranges previously reported for avian groups with similar feeding niches. Prey species (oysters, mussels, clams, whelks, blood arks, false angel wings) were similar in water content to vertebrate prey, moderate to high in protein and moderate to low in crude fat. Ash and macronutrient concentrations in prey species were high compared to requirements of carnivores or avian species. Prey items analyzed appear to meet nutritional requirements for oystercatchers, as estimated by extrapolation from domestic carnivores and poultry species; excesses, imbalances and toxicities – particularly of minerals and fat-soluble vitamins – may be more of an issue warranting further investigation.