Written by: Dr. Jacquie Jacob, University of Kentucky
Birds come in different shapes and sizes, but one thing they have in common is feathers. Feathers are unique to birds; that is, everything that has feathers is a bird. Figure 1 shows feathers of various sizes, shapes, colors, and purposes on an adult male rooster.
Fig. 1. Parts of an adult male rooster. Source: John Anderson, The Ohio State University.
Feathers play three main roles in birds' lives:
Figures 2 and 3 illustrate features of flight feathers, and Figure 4 shows a feather whose purpose is ornamentation.
Fig. 2. Parts of a feather. Source: Jesse Lyons, University of Missouri.
Fig. 3. Electron microscope image of part of a pheasant secondary flight feather. Flight feathers must be tough to withstand the rigors of flight. The barbs on a flight feather are strong and are connected to adjoining barbs of the same vane by the hooks on the barbules. Source: John Anderson, The Ohio State University.
Fig. 4. Electron microscope image of part of a peacock eye feather. This feather is ornamental and not meant to withstand the forces a flight feather must endure. Spacing exists between the barbs, and the hooks do not hold the barbs together. The ridges on the barbs are part of the complex color-producing system present on peafowl. Source: The Ohio State University.