Although rodents are an integral part of numerous carnivore diets, there is little published information regarding nutrient composition in free-ranging mice for comparison with laboratory-reared prey. Cotton mice (Peromyscus gossypinus, n ¼ 6) were captured on St. Catherines Island, Georgia, and analyzed for water, ash, protein, and fat content (proximate constituents), as well as minerals and the fatsoluble vitamins A and E. The overall body composition (mean7SD: 65.8%71.9% water, 10.9%72.2% ash, 56.4%74.1% protein, and 27.2%73.9% fat) was similar to published values for adult laboratory mice (Mus domesticus). The macro-(Ca, K, Mg, Na, and P) and trace (Cu, Fe, Mn, and Zn) mineral levels were also similar to previously reported values for laboratory mice, and in general met or exceeded the established nutrient requirements for domestic carnivores. Vitamin E ranged from 77 to 170 IU/kg dry matter (DM) in these mice-again, similar to values previously quantified in laboratory mice. However, the vitamin A concentrations (21,94776,893 IU/kg DM) in the free-ranging mice were consistently and substantially lower than values reported for whole laboratory mice. To our knowledge, this is the first quantification of vitamin A in free-ranging mice used as prey by carnivores. While other nutrients measured were similar between captive-reared and free-ranging mice, the current data suggest the need for further investigation of vitamin A nutrition in the development of optimal diets for carnivores in captivity.

The American oystercatcher (Haematopus palliatus palliatus) is currently listed as a species of high concern by the United States Shorebird Conservation Plan. Because nutritional status directly impacts overall health and reproduction of individuals and populations, adequate management of a wildlife population requires intimate knowledge of a species' diet and nutrient requirements. Fat-soluble vitamin concentrations in blood plasma obtained from American oystercatchers and proximate, vitamin, and mineral composition of various oystercatcher prey species were determined as baseline data to assess nutritional status and nutrient supply. Bird and prey species samples were collected from the Cape Romain region, South Carolina, USA, and the Altamaha River delta islands, Georgia, USA, where breeding populations appear relatively stable in recent years. Vitamin A levels in blood samples 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 broadly similar feeding niches such as herons, gulls, and terns (eg, aquatic/estuarine/marine). Prey species (oysters, mussels, clams, blood arks [Anadara ovalis], whelks [ Busycon carica ], false angel wings [ Petricola pholadiformis ]) 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 with 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 warrant further investigation.