Looking at this Black-billed Magpie's tail you can see it's been in a few tussles. I saw some Magpies this morning swooping at and scolding a Coyote to try to make it go away. They had a nest nearby. They were protecting their young. Nothing could be more important.
Usually Great Blue Herons move very slowly in the water and are very still before they pounce on their prey. In this case, though, this bird spotted a fish, ran wildly, then dove in for the capture.