compact wad of indigestible matter left over after the gizzard has ground food that has not been broken down in the proventriculus; pushed up the esophagus to be regurgitated (or “cast”); in Bald Eagles includes fur, scales, feathers, and teeth, but not most bones, which Bald Eagles can digest; Bald Eagles expel a pellet about once per day, typically in the morning, and not always correlated with a particular meal; also casting