Upper Midwest Environmental Sciences Center
Food habits of diving ducks in the Great Lakes after the zebra mussel invasion
Custer, C. M., and Custer, T. W., 1996, Food habits of diving ducks in the Great Lakes after the zebra mussel invasion: Journal Of Field Ornithology, v. 67, no. 1, p. 86-99.
Zebra mussels (Dreissena polymorpha) invaded the Great Lakes in the mid- 1980s and quickly reached high densities. The objective of this study was to determine current consumption of zebra mussels by waterfowl in the Great Lakes region. Feeding Lesser Scaups (Aythya affinis), Greater Scaups (A. marila), Canvasbacks (A. valisineria), Redheads (A. americana), Buffleheads (Bucephala albeola) and Common Goldeneyes (B. clangula) were collected in western Lake Erie and in Lake St. Clair between fall and spring, 1992-1993 to determine food habits. All 10 Redheads, 97% of Lesser Scaups, 83% of Goldeneyes, 60% of Buffleheads and 9% of Canvasbacks contained one or more zebra mussels in their upper gastrointestinal tracts. The aggregate percent of zebra mussels in the diet of Lesser Scaups was higher in Lake Erie (98.6%) than in Lake St. Clair (54.4%). Zebra mussels (aggregate percent) dominated the diet of Common Goldeneyes (79.2%) but not in Buffleheads (23.5%), Redheads (21%) or Canvasbacks (9%). Lesser Scaups from Lake Erie fed on larger zebra mussels (x super(-) = 10.7 plus or minus 0.66 mm SE) than did Lesser Scaups from Lake St. Clair (x super(-) = 4.4 plus or minus 0.22 mm). Lesser Scaups, Buffleheads and Common Goldeneyes from Lake Erie consumed zebra mussels of similar size.
Keywords: Aythya, Bucephala, food consumption, food selection, Dreissena polymorpha, USA, Michigan, aquatic birds, prey selection, freshwater molluscs, North America, Great Lakes, waterfowl, foods , diets , zebra mussels