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
What a Terrible World, What a Beautiful World of "Make You Better", stating "The band has never lacked the musical bona fides to write a great anthem." The album debuted at No. 7 on the "Billboard" 200 albums chart on its release, selling around 50,000 copies in the United States in its first week. It also debuted at No. 2 on "Billboard"'s Top Rock Albums, and No. 1 on the Folk Albums chart. The album has sold 123,000 copies in the United States as of October 2015. All songs written by Colin Meloy. According to the liner notes of "What a Terrible World, What a Beautiful World". What