Flighty Feathers

I just adore feathers! Out in the field while I'm working I always look for them, even when driving the swamp buggy will I stop just to jump down to take a picture of another exquisite feather that one of our beloved birds of corkscrew molted!

I started really taking an interest in feathers during my Vertebrate Anatomy course I took at USF. There Dr. Motta taught an extremely captivating lecture and lab regarding species. It was very informative and my favorite lecture was that of feathers and how they came to be! Allow me if you will to share the marvel that is feathers....

Flighty Feathers

Around 175 million years ago, feather-like filaments started to appear on dinosaurs who are the ancestors of todays birds. Scientists believe these filaments evolved to provide insulation or that they were for sexual display similar to what todays birds will use their feathers for.

Around 165 million years ago however did we first see evidence of the first flattened feathers showing that locomotion was beginning to change into aerial locomotion. It was believed that the ancestors of birds would evade their predators by running up trees. As they continually used this escape mechanism and flapped their wings, the feather-like structures started to evolve for a whole new purpose, flight.

The first bird-like dinosaur with true feathers appeared around 150 million years ago and was called Archaeopteryx.  The Archaeopteryx was the transition between non-avian feathered dinosaurs and modern birds that we know. It most resembled a Raptor, a close relative of the Archaeopteryx.

Extant birds of today use their feathers for display, insulation, camouflage, and flight. The feathers are shed once or twice a year; not all feathers are shed at once though.

There are two types of feathers, Contour (vaned) feathers and Down Feathers. The vaned feathers cover the body. The contour feathers include Flight feathers (remiges), Coverts, and tail feathers (retrices). The contour feathers on the wing, or the flight feathers, are used as air foils. By this, it is meant that the feather is positioned such that they rotate as the bird flaps its wings during aerial locomotion.

The muscles responsible for this locomotion are the erector-plus-rotator muscles and the retractor muscles that are found within the feather follicles along the linear feather tracts on the wings. Upon downstroke, the feathers rotate so that wind cannot move through them. Contrary to this on upstroke, the feathers rotate to allow wind to go through them. If this was not the case the bird would not be able to get lift.

Feathers have a quill, a shaft, and a vane made of barbs and barbules. The barbules have hooklets on them to keep the feathers together. When birds preen themselves, they not only waterproof their feathers but also rehook the barbules to put the feather back together.

The down feathers that are used in pillows have little to no shaft nor and hooklets. They are just short feathers that lie all over the body for insulation.

Birds have beautifully colored plumage. The warm colors such as red, orange, yellow, brown, and black result from pigments. White color on feathers are due to microstructure and light that passes through it. Blue and green iridescent colors are structural colors that result from light hitting the fibers of the feathers themselves.