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 Guilty Cage to cross off birds from his diet, saying to himself that "That one sort of upset my stomach!". A Bird in a Guilty Cage A Bird in a Guilty Cage is a 1952 "Looney Tunes" animated short featuring Sylvester and Tweety. The title is a pun on the song "A Bird in a Gilded Cage". Sylvester is at a store called Stacy's, where he notices Tweety in the window stand. Going through the package slot, he closes the curtains and climbs up to Tweety's cage, who asks him what he's going to do. After asiding to the audience, "How naive