Yesterday (04/02/13), a Common Black-Hawk (Buteogallus anthracinus) raided the two Great Blue Heron nests over my stock pound. I heard the screams and croaks, and later saw the hawk sitting in one of the heron nests. Today, I saw the hawk flying through the cottonwood grove beyond the heron nests, but the herons are gone.
Common Black-Hawks are not very common. The Arizona Game and Fish Department considers them “vulnerable to extirpation.” Black-Hawks are probably imperiled because they don’t tolerate human disturbances very well, and because they depend on cottonwood-willow vegetation in riparian habitats.
A pair of Common Black-Hawks regularly nest in the woods behind my ponds, but the herons started nesting by the ponds in 2011. It was unfortunate to loose the herons, but I have to choose the Black-Hawk. Herons are much more adaptable and widespread. They will be around after the Black-Hawks are all gone.