Flight feather, 2010
I have had the opportunity to do some illustrations for the recently published book by Thor Hanson: "Feathers: the evolution of a natural miracle." This is the illustration of the flight feather.
"Flight feather With its distinctive offset rachis, a flight feather can fit neatly between its neighbors to form a seamless wing or tail. But this shape also makes it remarkably aerodynamic on its own when those feathers are splayed. Flight feathers evolved from standard contour feathers and feature the same waterproof vanes with interlocking barbules. They can be brightly colored, elongated, or otherwise modified for breeding displays. In flightless birds, they often lose their aerodynamic qualities entirely and serve primarily for display, waterproofing, or other functions. Flight feathers are also known as remiges (singular: remex) for those on the wing and rectrices (singular: rectrix) when located on the tail. Remiges are further divided into primaries and secondaries, based on their position along the wing."
Text from "Feathers: the evolution of a natural miracle," by Thor Hanson. Copyright © 2011 by Thor Hanson. Used by permission of the author.