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
Calamus Swamp website, Calamus Swamp has a unique plant community. Because of the moist soil, trees such as the American Elm, Green Ash and, in places, Red and Silver maples make up the swamp forest. Calamus Swamp has a wide range of birds and animals: Because the Scioto River is only away, the lake attracts many migrating water birds, such as ducks, geese, grebes, and others. Mammals that have been spotted here include raccoons, muskrats, groundhogs, opossums, and white-tailed deer. The lake is home to other animals including the Ohio fairy shrimp, white leech, horse leech, giant water bug, pond snail, and