Mysteries of migration

In most areas of the country, changing seasons mean birds on the wing. Every fall, millions of birds that have nested in the United States and Canada fly south to wintering grounds in the southern United States, Mexico, Central and South America, and the Caribbean. Each spring, when the weather warms in the Northern Hemisphere, migrating birds leave their wintering grounds and return to the United States and Canada to breed. Watching bird migration in progress is an inspiring and simple way for children to learn about the remarkable rhythms of the natural world. Although much about bird migration remains one of nature's great mysteries, scientists have learned much about the "whys" and "hows" of bird migration. For example, we know that most migrating birds rely on a variety of the following senses and cues.

Photoperiodism, the lengthening and shortening of days in spring and autumn, affects birds' pituitary and pineal glands. These glands generate hormones that stimulate birds to become increasingly restless. Daytime migratory birds use vision to steer by the sun, aided by a precise sense of time. Night fliers take compass cues from star patterns. While in flight, birds may use geographic land forms to help them orient direction and course. The outline of North American coasts, and the north-south direction of many large rivers and mountain chains, aid in migration. Homing pigeons and some migratory birds see ultraviolet and polarized light to assist their migration.

Many scientists believe that migratory birds tune in to the earth's magnetic field in combination with gravity for direction. Birds usually wait to migrate until the passage of weather fronts. They make use of the favorable winds that follow storms to aid their flights. Most long-distance migrants have a highly developed respiratory system, hollow bones, internal air sacs, and specialized body shapes. Birds' pectoral chest muscles, which power their wings, are much larger and better developed in relation to overall size than are any similar muscles in mammals. Before migration, most species build up layers of fat. All of these features enable migrating birds to fly high, fast, and for long periods of time.

The destination to which birds migrate is generally determined by the presence of food, water, and shelter. The term migratory route indicates the general direction of flight that is annually followed by migrating birds on their journeys between wintering and breeding grounds. Migratory routes do not refer to exact, specific routes. Rather, birds tend to follow general north-south pathways between major habitats and avoid crossing obstacles such as mountain ranges.

Migratory birds and waterfowl cross international boundaries on their biannual migration to and from breeding grounds in Canada and the United States and wintering grounds in Mexico, Central and South America, and the Caribbean. As such, international approaches to conservation must be implemented to maintain populations of migratory birds. The U.S. Fish and Wildlife Service Office of International Affairs works in these countries to protect critical habitat, particularly wetlands, and to train wildlife managers in state-of-the-art wildlife and habitat conservation techniques. The U.S. Fish and Wildlife Service is also the lead agency in negotiating and enforcing international agreements and laws regulating the import and export of migratory birds and other wildlife.

In addition, the U. S. Fish and Wildlife Service carries out a variety of research and monitoring projects that help track bird migration, including bird banding, radio telemetry, and satellite imaging projects. These projects provide valuable information for conservation and management of migratory waterfowl, shorebirds, songbirds, and raptors. Activities in this section will:

Migratory Bird Collages


Grades: Primary

Objectives: As a result of completing this activity, students will be able to use color, shape, line, and texture to create a collage that communicates the concept of migration (ART), and demonstrate an understanding of the benefits that aid, plus the obstacles that hinder bird migration (SCIENCE).

Materials:

Instructions:

1) Tell students they will be making two collages. The first will represent all the items students would need to take a long trip. The second will represent all the items birds need to migrate.

2) Discuss with students all that they know about bird migration. How do they think a bird travels such a long distance without stopping? Discuss cues for migration, as outlined in the section overview, "Mysteries of Migration." Now create a list of all the items students think they would need to go on a road trip traveling a similar distance as the birds - such as a car, gasoline, rest stops, suitcases, etc.

3) Have students select a specific species for their collage. They may choose their adopted waterfowl or another species of their choice.

4) As homework, have students research their selected bird's migratory route and ask students to bring in old magazines from home.

5) Cluster students into groups so that they can share magazines. Distribute two copies of the Western Hemisphere map for each student. Have students trace the migratory route of their selected bird on one map. Have them trace the route of an imaginary vacation car trip on a second copy. Students will make collages of all the items their selected species needs to "migrate" on the first map. They will make a representation of all the things they need to migrate on the second map. Students may wish to add free hand drawings to fill out their collages.

6) Have several students present their migratory collages to the class and display collages around the room.

Evaluation:

Do the collages communicate an understanding of birds' requirements for migration? Can students articulate similarities and differences between a bird's migration and a long car trip?

I'll Fly Away

Grades: Primary, Middle

Objectives: As a result of completing this activity, students will develop ability in the use of symbols and drawings to tell a factual story (ART), and increase their understanding of the North American flyway (SCIENCE).

Materials:

Instructions:

Activity I: I'll Fly Away Murals (Primary)

1) Prepare for this activity by covering one wall or area of the classroom with white mural paper and drawing a large representative map of North America on the paper.

2) Divide the class into four (or eight) groups of no more than four or five students each. Assign one of the flyways to each of the four (or eight) groups - Atlantic, Mississippi, Central, and Pacific. Explain that flyways generally follow major coastlines, river systems, and mountain chains. Have the groups refer to the flyway maps to identify where each of the flyways originates and ends.

3) Distribute crepe paper and have groups attach crepe paper streamers to the wall mural map to represent the flyways from beginning to end. For example, the Pacific flyway originates in Alaska and extends roughly southward along the Pacific coast into northwestern Mexico.

4) Now have students embellish their flyway murals by using paints to add other geographic, physical, and living features they might find along their flyways. Examples include mountain chains, rivers, major cities, lakes state boundaries, etc.

Activity II: North American Flyways and the National Wildlife Refuge System (Middle)

1) Distribute maps of the National Wildlife Refuge System. Explain to students that the National Wildlife Refuge System now includes more than 500 refuges. Most refuges are aligned more or less along major flyways. This is because many refuges were originally created to provide safe habitat for migrating waterfowl. Waterfowl require habitat throughout their flyways and National Wildlife Refuges represent "links in a habitat-chain.

2) Have students identify five to ten refuges located on their designated flyway. Have them identify the approximate locations of these refuges on the way flyway murals. Now have them either write the names of the refuges, or paint representative images of the refuges at the approximate locations on the flyway mural maps.

3) Distribute field guides. Have students select one waterfowl that migrates on their flyway. Distribute 8 ½ " by 11" sheets of paper. Have them paint images of their birds and cut silhouettes of the birds from the paper. Now have students adhere their waterfowl on their flyways.

Evaluation:

Do students' flyway mural maps in Activity I exhibit an understanding of the North American flyways? Do students flyway murals in Activity II represent an understanding of the relationship between the location of National Wildlife Refuges and the North American flyways?

Waterfowl Anatomy

Grades: Middle, Secondary

Objectives: As a result of completing this activity, students will create line drawings to represent the external anatomy of a bird (ART), and demonstrate an understanding of bird anatomy (SCIENCE).

Materials:

Instructions:

1) Hold a general discussion on the essential aspects of bird physiology. What anatomical features allow birds to fly, many for long distances, during migration? What features allow ducks to float, swim, and stay warm in cold water? Do students know which species represents the largest bird and which represents the smallest bird?

2) Distribute waterfowl anatomy worksheets. Review the terms used to identify various parts of a bird's external anatomy. Pay particular attention to the specific features that enable waterfowl to fly and swim including hollow bones, strong pectoral muscles, and webbed feet. Review anatomical terms with students.

3) You may wish to provide a blank copy of the waterfowl anatomy diagram and have students identify anatomical features on the blank diagram to enforce learning.

4) Cluster the class into groups of four students each, and distribute reference materials and field guides. Ask members of each group to select either a duck, swan, or goose.

5) Tell students they will each be making an anatomical sketch of their bird. Ask students to identify the species they selected in a field guide.

6) Students will begin by making a simple line drawing of the species they selected and by identifying its anatomical features.

7) Students should make their illustrations detailed enough to highlight as many anatomical features as possible. Have several students present their illustrations to the class. Display illustrations around the room.

8) (Optional) Obtain a slide show, or compile individual species slides of various migratory birds. Show a series of slides of waterfowl, shorebirds, raptors, and songbirds, pausing long enough at each slide for students to develop a quick line sketch noting the species' particular anatomical features. After you have finished showing the slides, have students identify the specific anatomical features they have sketched.

Activity II: Anatomy Sculptures

1) Have students make papier mache or clay sculptures of the birds they sketched. Once the basic structure is in place, have students paint their sculptures to highlight as many anatomical features as possible.

Evaluation:

Do student drawings reflect an understanding of the external anatomy of their selected species? Do students' sculptures represent an ability to manipulate the materials (clay, papier mache, other materials) in order to develop a three dimensional form of their bird's anatomy?

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