I heard this peeping from the bushes in front of my house. I investigated, and it kept going, and didn't even move away from me. It's a baby catbird. It's at the stage where it can't quite fly, but it can get around pretty well, and it's parents will still feed it. It may have left the nest too early. This is the age of the birds that people usually find near their homes and want to take care of. DON'T. After I shot this video my dog tried to eat the bird so we left.