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
USS Calamus (AOG-25) as did the combatant ships. While at Okinawa "Calamus" was beached as a result of Typhoon Louise, 9 October 1945, refloated 24 October 1945, repaired and returned to service. Following occupation service, "Calamus" returned to San Francisco, California, 20 March 1946 and was struck from the Navy list (date unknown). She was decommissioned 15 May 1946, and transferred to the Maritime Commission 4 September 1946. Final disposition: she was scrapped in 1964. "Calamus" received one battle star for service in World War II. Her crew was eligible for the following medals: USS Calamus (AOG-25) USS "Calamus" (AOG-25) was a "Mettawee"-class