Eagles have the unique feature of the pecten. This find became known as the Pecten Beds. The lower valve of this species is less convex than in "Pecten excavatus". The bird retina has a fan shaped blood supply system called the pecten. Along the edge of the beak, there is a comb-like structure called a pecten. The pecten is a specialised structure in the avian retina. "Pecten jacobaeus" can reach a length of about . The name "Pecten" is from the Latin word for a comb or rake. The pecten is also used to preen feathers and to hold slippery food items.