Pin feather protective peripheral sheath, longitudinal barb ridges, and growth plates. Over time these barb ridges lengthen helically, branch to create barbs and barbules, and fuse to form the rachis or central shaft. Moreover, the barb plate further differentiate into hooklets and cilia, while the marginal and axial plate die to form the intervening space within the feather structure. During moulting, a bird may get careless and begin to chew at its feathers and might accidentally damage a blood feather. To prevent this, it is necessary that the bird is given chewing toys so that it does not chew at its own
What Bird is That? Edition What Bird is That?" was published by Australia's Heritage Publishing in 2011, the latest release of Cayley’s “big bird book” complete with Lindsey’s revisions. It is 832 pages, features 769 birds and includes all 460 of Cayley’s full-colour paintings, many showing groups of related birds. New to this edition was an accompanying e-book "What Bird Call is That?", which identifies and illustrates 101 birds from "What Bird is That?", as well as providing sound files of each featured bird’s distinctive call. The sound files were provided by David Stewart. "What Bird is That?" plays a central role in Australian