Feather These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so the barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular "calamus" (or quill) which inserts into a follicle in the skin. The basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base (proximal umbilicus) and a small opening on the side (distal umbilicus). Hatchling birds of some
A Bird in a Bonnet A Bird in a Bonnet A Bird in a Bonnet is a 1958 "Merrie Melodies" animated short starring Sylvester and Tweety. Released September 27, 1958, the cartoon is directed by Friz Freleng. The voices were performed by Mel Blanc, Daws Butler and June Foray. Granny visits a 1950's New York City hat shop looking for a new hat. The sales lady has her try on several hats, but Granny seems unsatisfied with each choice (a Napoleon chapeau makes her imitate Napoleon's hand in coat pose and chuckle "Not tonight, Josephine!"). Meanwhile, Sylvester is chasing Tweety outside and Tweety makes his