Food: Buffleheads consume mostly animal material. Insects make up 70 percent of summer foods in freshwater habitat. Midge, mayfly, and caddisfly larvae, and naiads of dragonflies and damselflies are also consumed. Water boatmen are the most widely distributed, important food. Plant food was found in many stomachs but much was fiber and was probably taken while catching aquatic insects. Pondweed and bulrush seeds were frequently consumed plant items. Dragonfly and damselfly larvae are important in the diet of ducklings in all areas (Erskine 1971). Hooded merganser _Lophodytes cucullatus_ L 13″ W 26″ [Illustration] Habitat: Although hooded mergansers prefer wooded, clear water streams, they also use the wooded shorelines of lakes. Drainage of swamps and river bottoms, removal of snags, and other human activities have been detrimental to this species as they have been to wood ducks. Hooded mergansers are more easily disturbed by man and far more sensitive to a decline in water quality than are wood ducks. Breeding densities often seem more related to food abundance and availability than to nesting cavities (Johnsgard 1975). Nest: Cavities at any height may be selected in any species of tree; the size and shape of the cavity are apparently not important (Bent 1923). Natural cavities chosen are similar to those used by wood ducks but with smaller optimum dimensions. Frequent use of nest boxes has been reported in Missouri, Mississippi, and Oregon (Bellrose 1976). In Oregon, boxes were placed 30 to 50 feet apart in sets of 8 (Morse et al. 1969). Some of the most southerly nesting records of this species are from wood duck nest boxes (Bellrose 1976). Food: The food habits of hooded mergansers are not well known, but are apparently more diversified than those of common mergansers. Of 138 stomachs taken from various locations in the United States, rough fishes made up 24.5 percent, game fish and unidentified fish fragments 19.4 percent, crayfish 22.3 percent, other crustaceans 10.3 percent, and aquatic and other insects 13.4 percent (Palmer 1976). Acorns are sometimes eaten in large quantities. Frogs, tadpoles, and molluscs such as snails are also consumed. Common merganser _Mergus merganser_ L 18″ W 37″ [Illustration] Habitat: Common mergansers prefer cool, clear waters of northern boreal or western forests, although at times they have nested as far south as North Carolina and Mexico. Ponds associated with the upper portions of rivers in northern forested regions are often used (Johnsgard 1975). As with hooded mergansers, clear water is needed for foraging.