Hard-headed

An immature male blue jay has been pounding himself silly and driving us crazy by attacking his own image as reflected in the glass in the fixed transoms. All other windows and doors are protected by screens and so, even if they were to produce a reflection apparent to him through the mesh, he wouldn't be able to reach the glass. We keep forgetting what the noise is. It's a very loud rap, and always repeated several times. Luckily the sun is just right for him to see himself only at a certain time of day.