Folks,
I heard an old-time naturalist give a talk about a heron colony in Minnesota that he had studied for years. He had great data on reproduction, survivorship, food preferences, behavior. He liked to follow individuals from the colony to their feeding areas Most seemed to specialize in hunting particular habitat types - farm ponds, cattail marshes, lake edges. They seemed to specialize in particular prey types, too. One heron hunted 13-lined ground squirrels at a rock quarry every day. It didn't sound like a very pretty scene, but the heron was fat.

John Fleckenstein
Olympia