The arctic tern is an amazing migratory bird, traveling over 22,000 miles in a year from the Arctic to the Antarctic and back again. Students will map this bird's migration route and consider why it wants to migrate so far. They will conclude by writing paragraphs describing the arctic tern's migration route and explaining how they think it knows when it's time to migrate.

Geography, life science

Standard 9: "The characteristics, distribution, and migration of human populations on Earth's surface"

Two to three hours

• Computer with Internet access
• Globe
• A small bird cut out of paper
• Wall map of the world
• Blank Xpeditions outline maps of the world
• Writing and drawing materials

Students will

• do a simulation to learn about the seasons in the Arctic and Antarctic;
• map the arctic tern's migration route;
• label the continents and bodies of water the arctic tern flies over;
• list the reasons they think the arctic tern migrates each year;
• write paragraphs (or draw pictures) about the arctic tern migration; and
• illustrate their paragraphs.

Hold up a globe, and ask one or more students to point out the North and South Poles. Explain that the regions around these poles are called the Arctic and Antarctic regions. Draw a circle on the board to represent a globe, and write the word "Arctic" at the top of the circle. Write the word "North" next to "Arctic." Write "Antarctic" and "South" at the bottom of the circle. Throughout this lesson, students should be able to refer to the board to remember that Arctic means north and Antarctic means south.

Ask the class what the weather is like in these areas. They should recognize that these are the coldest parts of the Earth.

Tell the class that even in the Arctic and Antarctic regions, there are definite seasons. In summertime, these regions are sunny almost all of the time, although they are still pretty cold. In wintertime, they are dark almost all of the time and extremely cold. How would they like to live in a place that's always dark and cold?

If students have not yet learned about why seasons occur, this would be a good time to introduce them to this concept. Have them do the first activity in this There is a Season lesson. It won't take long but will show them why the polar regions have opposite seasons and why one is dark while the other is light.

Ask students if they would like to spend a winter in either the Arctic or the Antarctic. What do they think it would be like? What would they have to do to survive?

Explain that almost no one, including animals, really likes the weather in the Arctic and Antarctic regions during the winter. Animals who live there during the summer generally migrate to warmer places during the winter—wouldn't your students do the same?

Have students look at this picture of the arctic tern. Ask them to guess how far this little bird can fly at one time.

After they have placed their guesses, tell them that the arctic tern can fly over 11,000 miles at a time! That's a one-way trip from the Arctic to the Antarctic.

Have students look at this animated globe (scroll down the page). It shows an arctic tern flying its migratory route between the north and the south. Explain that the bird doesn't fly north and south continuously as in this animation, but it stops to breed in the Arctic during the northern summer and to feed in the Antarctic during the southern summer. It does fly in the direction indicated by this map—south through Europe and Africa, and then north along the coast of South America.

Have one or more students come to the front of the room and run their fingers along the arctic tern's migration route on a world wall map. Ask them to stop their fingers at the top of the map (the Arctic), and ask the class to state the months when they think the arctic tern would live up there. They should say June, July, August—northern hemisphere summer months. If they find this tricky, ask them to think about whether they are closer to the Arctic or the Antarctic and when summer occurs where they live.

Have the students at the front continue running their fingers down the map to the Antarctic. Ask them to pause there, and ask the class to state the months when they think the arctic tern would live down south. They should say December, January, February—southern hemisphere summer months. Explain that, as they have seen demonstrated with the globe, the seasons are the opposite in the northern and southern hemispheres.

Students should realize that wherever the arctic tern lives, it is always summer. When the tern is in the Arctic, it's summer. It migrates south when autumn arrives in the north, and ends up in the south for another summer. Ask students what they think this tells us about the type of weather the arctic tern likes. It doesn't like extremely hot weather, but it doesn't like extremely cold weather either. It also likes a lot of sunshine. In order to get just the right weather and sun, it must fly this great distance twice a year.

Give students blank outline maps of the world. Ask them to draw the arctic tern's route, using arrows to show which direction it travels.

Discuss the arctic tern's route as a class. What continents does it fly over or near? What bodies of water does it fly over? Have students label some of these features (e.g., Atlantic Ocean, Africa, or Europe) on their maps.

Have students look at these pictures of arctic terns as you read the accompanying text. Explain that these activities—laying eggs and hatching chicks—take place in the Arctic, not in the Antarctic. The Arctic offers plenty of rocky places for them to lay their eggs and plenty of fish for them to eat. Students can draw pictures of eggs and chicks on their maps to illustrate this point.

Have students watch the video of the tern feeding and listen to the sounds it makes. Ask them to describe what the chick looks like and what the birds sound like. Explain that these birds are enjoying their summer up north but must prepare themselves for the flight south. Once the babies grow up a little, they will be ready to fly.

Review what students have learned by asking them to list the reasons they think the arctic tern would want to migrate such a long distance each year. They can make these lists individually or as a class, but be sure to discuss their lists as a class.

Ask students to imagine this scenario:

You are an arctic tern. It is August. That means you are living in the Arctic, not too far from the North Pole. August is at the end of the summer. Soon, you will begin your migration south. It will take you three months to get there. How will you know when it's time to leave? How do you know when summer is over in the north?

Ask students to think about these questions, and discuss their ideas as a class. Students should consider changes to the weather and the shortening of the days. Encourage them to think about what happens in their own area when autumn approaches, and explain that it's not that different way up north.

Have students write paragraphs that

• describe the arctic tern's migration route;
• explain how they think the arctic tern knows when it is time to head south; and
• explain why the arctic tern migrates in the first place.

Have students illustrate their paragraphs by drawing pictures of arctic terns, or tracing pictures of arctic terns and coloring them in. They can find pictures at the Birding America site and outline drawings at the U.S. Fish & Wildlife Service site.

Younger students who are not yet able to write paragraphs can contribute words to a class list describing the three points above. They can then draw pictures showing arctic terns in their northern breeding grounds and along their migration route.

Ask students how they think the arctic tern finds its way from the Arctic to the Antarctic and then back again. How does it know which way is north or south? Have the class brainstorm ways that this bird might navigate.

Write these words on the board: "Sun," "Stars," "Continents." Ask students how they think arctic terns might use each of these three features to navigate. Give students hints if necessary, such as "Have you ever seen a star that shows which direction it is in the sky?" or "Does Africa have a shape that's easy to recognize?"

Explain that birds, including arctic terns, use a variety of natural features to help them find their way. They were also probably born with some knowledge that tells them when to fly and where to go.

You can introduce students to the concept of geomagnetic navigation by saying that migratory birds may be able to detect special magnetic pulls from the Earth's poles, similar to the way that a magnet attracts paper clips (but much more gently!).

Have students write additional paragraphs or draw additional pictures illustrating some of the ways that arctic terns find their way between the Arctic and the Antarctic. Alternately, have them illustrate these concepts directly on their maps.

Alaska Department of Fish and Game Wildlife Notebook: Terns
Audubon Society: Arctic Terns
Birding America