fluffy dark gray bird

by Kathleen
(Lakeville MA )

Today we had a 'fluffy' dark gray bird with a lighter gray belly and black mohawk type crest. I couldn't get a picture of it, but it did hang around a few minutes. It was singing and constantly shaking its wings and tail feathers.It was approximately 6-8 inches and 3-4 inches wide. Does anyone have any ideas what it could be?