Skua feeding on bait ball and hassling terns and gulls
juvenile, scavenging carcasses of little blue penguins
Awful photos. It flew in from the ocean over the pond, freaking out all the shorebirds/stilts, and kept on going. They do winter here, according to the Audubon field guide. I can't think what else it might have been.
Pomarine Skua. Stercorarius pomarinus. Please acknowledge any use of this photo: Andy Jones, Cleveland Museum of Natural History.