Feather

Feather

1. Function

   • Most basic function of bird feathers is protection.
     • Birds need their feathers to protect their body.
       • When birds are hot, they compress the feathers to eliminate these heat-trapping pockets of air.
         • The gland secretes an oil that the bird squeezes out with its bill and then applies to its feathers for waterproofing and also for inhibiting the growth of fungi and bacteria.
     • When its cold, feathers trap air underneath, Bird feathers also serve as raincoats.

2. Structure

   • The typical contour feather is made up of a central shaft and a vane.
     • The pointy end of the feather is the hollow opening where when the feather was growing it received nourishment.
       • The vane is made up of numerous barbs or rami, small toothpick-like rods arranged in a closely parallel fashion on both sides of the rachis
         • There are usually several hundred barbs in each web.
       • There are microscopic hooklets (barbicels or hamuli) that help lock the barbs in place.

3. Types of Feather

   • VANED: Form the outer coverings of a bird's body, including the wing & tail feathers.
     • Down: Layer of loosely structured feathers beneath contour feathers which help to trap air near the birds body for warmth.
       • SEMIPLUME: Loose & fluffy feathers similar to down feather; provides body insulation and increases the buoyancy of water birds.
         • FILOPLUME: Small hair-like feathers with a few barbs at the tip of the shaft; they occur among the contour feathers.
           • BRISTLE: Modified, vaneless contour feathers with only a few barbs at the base on a small, stiff rachis. They can occur around the eyes, nostrils, and in flying insect-catching birds around the mouth.
             • POWDER DOWN: Feathers that grow continuously and are never molted. The barbs at their tips constantly disintegrate into a fine, talc-like, water-resistant powder.