Nutrition
Buffleheads are omnivores, but plants are not a big part
of their diet. They usually eat aquatic invertebrates;
however, they do occasionally eat some seeds. During
breeding season, when they are living by bodies of
freshwater, they tend to eat insects such as
damselflies,
dragonfly larva, and midge larva. When they are living by
saltwater in the winter, they tend to eat crustaceans and
mollusks such as snails, shrimp, clams, and sometimes fish.
Plants are more likely to be consumed in the fall and
winter. When buffleheads do eat plants, they lean towards
pondweed seeds and bulrush seeds. Sometimes 
they
participate in the multi-species flock that eats herring
eggs in the Pacific.
These ducks dive for their food and swallow it while they are still underwater. Since they do not dive through vegetation to get their prey, they feed in shallow waters that do not contain a great amount of vegetation. If they are feeding in flocks, some will stand guard and watch for potential dangers while the others dive for prey.
