Why compare birds and telephone poles to staff?

I've seen this picture. Several birds are hiding on the wire. The image of each bird seems to be a note on the staff, and the arrangement distance is appropriate. Several transmission lines are relatively straight, and the background is just quite empty, like a blank sheet of paper. The photographer captured this natural scene in time, and a "staff" with similar appearance and more similar spirit was vividly placed in front of the readers, which could not help cheering for the photographer's inspiration! * * * Singing and smiling from the heart.