The Feathers of Birds Flock Together

SCIENCE CONCEPT:

Birds have between 1,000 and 25,000 feathers, depending upon the species. Obviously, larger birds have more feathers. The swan with its long neck has the most. Feathers can be divided into six categories. Students will be introduced to the various feather types and study them under a magnifying glass.

STUDENT OBJECTIVE:

For the students to learn the function of the six categories of feathers. After viewing the different types of feathers under a magnifying glass the students will draw them on artist paper. This will give them a first hand view of the feathers that make up the outer scaling of birds and how these feathers contribute to the ability of a bird to fly.

OVERVIEW:

The fascination with natural flight is a phenomenon that has always captured the minds and imaginations of people. In studying the feathers of birds students will have a closer look at part of the elements that make up the bird's ability to fly. Feathers can be divided into six categories so there is an abundance of viewing for the students to participate in.

PREPARATION TIME:

20 minutes.

LESSON TIME:

40 minutes.

TEACHER PREP:

Gather as many of the six different types of feathers for the students to view under the magnifying glass. Suggestions for locating the feathers: call a local zoo with a bird sanctuary, contact a pet store with birds, or a private resident who has their own birds.

WORDS TO KNOW:

contour

rachis

shaft

hollow

pulp

vanes

barb

barbules

hooks

semiplume

down

quill

filoplume

bristles

powder-down

TEACHER TEXT:

Feathers can be divided into six categories. The contour feathers are the most abundant and cover the outer surface of the bird, giving the smooth, sleek profile so important to flight. All contour feathers have the same basic structure, with modifications depending upon placement and function. There is a central rachis, or shaft, which is hollow. Inside, dried remains of the pulp form strengthening struts which run crosswise like ladder rungs. The vanes are the two halves of the feather that spread out from the shaft. They are made up of hundreds of branches called barbs, angling toward the tip of the feather. Each barb has tiny, parallel branches of its own called barbules. The vanes are smooth because of the structure of the barbs and barbules. As the feather bends and twists during flight, the barbule hooks slide back and forth retaining the smooth but flexible shape. However, a reverse twist from the tip to the base will separate the barbs and make the feather ragged with spaces in between. Preening "re-zips" the barbs and barbules. The barbs at the base of a contour feather have no hooks and so they appear fluffy.

The second type of feather is the semiplume. It is shaped like a contour feather, but its' shaft is not as stiff and its' barbs have no hooks so are fluffy. The third type is the down feather. It is fluffy like the semiplume but has a very short shaft. Both the semiplume and the down feathers are important for keeping the bird warm. The fourth feather type is called the filoplume. These are tiny and delicate with only a few barbs on the tip. They are sparsely scattered among the other feathers. Bristles are stiff, hairlike feathers found only in some birds. This makes up the fifth category of feathers. Their function is specific in each species. Bristles are found around the mouths of birds who scoop insects out of the air. Bristles are found covering the nostrils of woodpeckers, and in ostriches they form eyelashes.

The sixth and last type of feather is only found in a few birds. It is the powder-down feather. This feather grows continually. The tip breaks off forming a water resistant powder. The metallic sheen of the heron is caused partly by this powder down. A bird's wing is the basic structure for flight. It is covered with the contour feathers that are specialized for flight. It is the shape of the wing that enables a bird to fly, and the shape is determined by the feathers.

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Last modified: Sat Aug 23 14:04:12 PDT 1997