Bird topography and feathers

Figure 4. Feather Structure
TYPES OF FEATHERS. There are five principal types of feathers (Fig. 5):
(1) Contour feathers give shape and a smooth protective surface to the body and are
used for flight in the wings and tail. Contour feathers vary considerably in shape, size, and
texture over the body. This is the typical feather just examined.
(2) Down feathers are small, with poorly developed shafts and no interlocking barbules.
They are the principal feather type in young birds and are important as insulation in most birds.
They lie under the contour feathers. Powder down is a specialized type of down best developed
in herons. They are yellowish and grow in two patches on the breast. The other feathers are
dusted with the powder produced by these feathers.
(3) Semiplumes are intermediate between contour feathers and down feathers. They
have a large rachis but no hooks.
(4) Filoplumes are hair-like feathers that can be seen after all other feathers have been
plucked from a bird. There are barbs only near the tips. They are thought to provide a sense of
touch in the plumage, much like the small hairs on human skin do.
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