The base of my small tube feeder, had about a half dozen english sparrows and house finches on it this morning. A gray squirrel approached the feeder, and jumped from the rail of my back steps to the feeder. In the process, landing on a female house sparrow. He promptly bit the back of her neck, and killed her. He then ran off with her in his mouth, and ate her in my neighbors maple tree. Opportunistic feeder, or predatory gray squirrel? It really surprised me.