There was a hullabaloo in the small woodlot near the Sharing Farm at Terra Nova, a male Cooper's Hawk flapping back and forth, calling loudly. If you look closely at the bottom of the picture, you will see the cause of his agitation.
Or rather, half the cause. In this image, hawk is in the lower left, squawking at not one, but two Great Horned Owls.
Which you can see more clearly here.
The hawk kept flying back and forth, and the owls' heads swivelled as if watching tennis. Finally one of the big birds looked at me. I was clearly the lesser annoyance.