Herons and cormorants have very different styles of hunting. The herons (and their family members, the egrets) stay mostly still on the water’s edge, waiting for something to swim within range. The cormorants go into the water and chase their prey in repeated dives. It’s passive v. active. Can those two styles coexist in a small body of water, such as the immediate outflow of Schoolhouse Creek? The Great (white) Egret didn’t seem to have any problem. But the Great Blue Heron wouldn’t hear of it. After watching the cormorant at close range, and seeing the diving bird stomach more than one little fish, the Blue picked his moment and jabbed at the cormorant with its formidable beak, wings spread high. The cormorant did a panic dive and got out of Dodge.
This Blue — I assume it’s the same one — now has quite a track record of being bossy. I watched it try to intimidate a Black-crowned Night Heron up on the east side of the seasonal Burrowing Owl sanctuary, see “Heron Harassment” June 20, 2021. And then I saw it chase away a gull, for no good reason, near the Open Circle Viewpoint, “Tough Pull” July 21 2021. It hasn’t actually injured anyone, that I’ve seen, but nobody wants to take chances with that long shiv of a beak.
I noticed that the Great Egret got out of the way as the Blue approached the cormorant. Then, at the exact moment that the Blue attacked the waterbird, the egret also quickly spread its wings as if involved somehow in the attack. This looks like some kind of involuntary empathetic reflex or mirror neuron reaction. I’ve not seen that before. Curious.
The only time I’ve seen the big egret and the big heron tangle with one another was an aerial engagement that might have been a dogfight or a race for fun; check out “Race of the Greats” December 3 2017.