Today D. and I saw an otter eating a dead pelican in Rodeo Lagoon, just north of the Golden Gate Bridge. I thought they only ate fish and shellfish.
A woman who pointed out the otter to us said that a family of 5 otters was living in that lagoon, and they caught birds by swimming up from below them in the water and grabbing them before they know wth is going on.
According to Wikipedia, otters will also eat frogs, crayfish and crabs; some will also take any available small mammals or birds. So it's true you learn something new every day.