Animal, vegetable, or mineral?

Yesterday I was out in the backyard and heard this weird bird noise. I can't describe it. Duckish? No. It was kind of screechy, but deeper and raspier. I walked toward the sound and stood under the tree where I heard it the loudest, wondering what kind of strange fowl was going show itself. And what kind of bird was it? It was a squirrel. And while I stood there looking up at it less than ten feet away, it looked down at me and kept screeching and chirping away. The arrogant bastard!