FORAGING BEHAVIOR AND ANALYSIS OF WHOLE PREY EATEN BY THE AMERICAN OYSTERCATCHER (HAEMATOPUS PALLIATUS)

As part of a continuing study using the American oystercatcher ( Haematopus palliatus), populations as biomonitors of coastal habitat quality 6 , foraging behavior was quantified, and primary food items obtained for nutritional analysis during June and July, 2002. Two southeastern US barrier island sites were sampled: St. Catherines Island (SCI), GA and Cape Romain National Wildlife Refuge, SC. Bivalves including blood ark clams (Anadara ovalis), Eastern oyster (Crassostrea virginica), and false angel wings (Petricola pholadiformis) were identified as prey items, along with knob whelk (Busycon carica). These marine invertebrate species were subject to whole prey analysis including proximate composition (water, crude protein, crude fat, and ash), fat-soluble vitamins A and E, and mineral content. Water content of meat from the whelk (73.4 ± 1.7%) and larger bivalves (oysters and blood arks; 79.9 ± 0.3 to 83.8 ± 0.5%) was higher than that of tiny false angel wings (60.0 ± 2.0 to 62.9 ± 5.8%); the latter were consumed with the shell intact. Fat content ranged from 6.5 ± 0.1% in false angel wings to 14.7± 1.4% (dry matter, DM, basis) in Eastern oysters, and fat content was quite variable in oyster samples collected from SCI. C. virginica had the highest vitamin A and E values, while P. pholadiformis had the highest Ca. Foraging activity may be affected by height of tide, human disturbance, as well as seasonal food quality and availability. This summary of foraging and whole prey nutrition data establishes baseline values for future comparisons and guidelines for captive feeding programs.