Chapter 6: Brant Migration

In this unit, students will learn some of the challenges that the Brant face during their migration. A mapping exercise will introduce students to the idea of ‘bird banding’ and the use of band reports.

Migration Headache

Subject:
science, mathematics, physical education, social science
Duration:
45 minutes
Group size:
20 and larger
Setting:
indoors or outdoors, large area for running
Topics:
flyways, migration, wintering habitat, nesting

Objectives:
1. Students will learn that Brant are dependent upon their environment for survival.

2. Students will be able to list limiting factors affecting migratory Brant populations, predict the effects of such limiting factors, describe the effects of habitat loss and degradation on Brant populations, and make inferences about the importance of suitable habitat for migrating Brant.

Method:
Students role-play migrating Brant traveling between nesting areas and wintering grounds. The Brant are subject to hazards at either end of the migration path as well as along the way.

Background:
What is migration?
Migration is the seasonal or periodic movement of birds or other animals from one area to another. Migration has long been considered a mystery. How do animals (birds, mammals, fish, etc.) know when to leave? How do they know where to go? How do they navigate the long trip without a compass? Scientists have proposed that they use the stars, the sun, and even the earth's magnetic field to guide their journey. No one knows for sure how it works.

What is a flyway?
A flyway is like a bird superhighway. There are four such "superhighways" in North America that run north and south. The Pacific North American Flyway is the name of the flyway used by the Brant. It starts in Baja California and the west coast of mainland Mexico. The flyway then continues up the west coast of California, Oregon, Washington, Canada and finishes in Alaska.

How do birds prepare for migration?
In preparation for a long migratory flight many birds have to build up extensive energy reserves. For the Brant, this means feeding heavily on eelgrass and sea lettuce. Such reserves (fat supplies) are required to help the Brant make it all the way to their nesting or wintering grounds.

What are nesting and wintering grounds?
A nesting ground is that area used by birds to mate, build a nest, lay eggs, and raise their young. The Brant's nesting grounds are in Alaska, northwestern Canada and northeastern Russia.

Wintering grounds are areas where birds spend the winter. Many migratory birds fly south in search of their wintering grounds. Here they find warmer temperatures and an increased abundance of food. The Brant fly south from their northern nesting grounds in the arctic to reach their wintering grounds. Most will head straight to Mexico, although some stop along the western coast of North America. Some have even been known to go to Japan!

Why are wetlands important during migration?
Migratory Brant require the presence of wetlands in their breeding habitat and on their wintering grounds. Since these two regions are thousands of miles apart, the Brant also need wetlands to provide them with food and rest, especially during their northward migration.

Why do birds migrate?
It is thought that seasonal changes in weather, which affect the availability of food and water, is the main reason for which migration occurs.

What are the hazards encountered during migration?
Some people question why birds migrate when so many obstacles are encountered along the way. Such obstacles include bad weather (storms can blow them off course), hunting pressures, destruction of habitat (wetlands) along the flyway, predation, pollution, pesticides, etc.

Materials

Procedure:
1. Select an area about 70 feet in length. Place the paper plates in two locations on the playing field as shown below:

There should be one plate for each three students at each end of the field. Place the sign which designates "Wintering Habitat" at one end and "Nesting Habitat" at the other end.

2. Explain to the students that they are Brant and will migrate between these two areas at your signal. Tell them that each paper plate represents a "wetland," suitable habitat for only three Brant (students). At the end of each migration the students will have to have one foot on a paper plate in order to be allowed to continue. If they cannot get their foot on a plate then they weren't able to get suitable habitat. They "die" and have to move, at least temporarily, to the sidelines and watch.

3. Explain to the students that many factors limit the survival of populations of migrating Brant. Some involve changes in the wintering and nesting habitats. There will be times of abundant food, water, shelter, and space suitably arranged to meet the habitat requirements of the Brant. There will be other times when the habitat is stressed, with many factors limiting the potential for survival. Sometimes the area of available habitat is reduced.

4. Begin the activity with all the students at the wintering habitat. On the first try, all the birds will successfully migrate to the nesting habitat. Explain that there has been no loss in available nesting habitat. Thus, a successful nesting season is at hand.

5. Before the students migrate toward the wintering habitat, pick up one of the plates from the wintering region. Explain that a large wetland area has been drained and used for agricultural purposes. Repeat the instruction to migrate and send the birds to the wintering habitat. Have the three students that will be displaced stand on the sideline. Tell the students that these three have died as a result of loss of habitat. Remind any "dead birds" that they will have a chance to get back into the activity. They can come back as surviving hatchlings when favorable conditions prevail and there is habitat available in the nesting ground.

6. Before the next migration to the nesting region, pick up four plates in the nesting habitat. This represents a catastrophic loss. Tell the students that this is the result of a period of unusually heavy rain during nesting which flooded many of the nests. Instruct the students to migrate. This results in a large number of students waiting on the sidelines to reenter the nesting habitat. Before many cycles are repeated, provide them with an opportunity for reentry. Each time, give the students examples of changes in habitat conditions that could have taken place making it possible for them to survive. Two students can be made permanent monitors to place the paper plates down or pick them up as you instruct them.

7. Repeat the process for eight or ten migration cycles to illustrate changes in habitat conditions with resulting effects on the Brant. Give examples of factors that might influence the Brant's survival.

Factors Reducing Survival:

Factors Favoring Survival:

NOTE: Some limiting factors are a natural and dynamic part of any environment. This is true of factors favoring survival as well. Be sure to create one or more "disaster" years to illustrate catastrophic loss of large areas of available habitat. Remember that, overall, the availability of suitable habitats for Brant are diminishing. The activity should end with fewer areas of available habitat than can accommodate all the birds. There is general agreement that the greatest long-term threats to the survival of Brant populations are the loss and degradation of habitat.

8. Hold a class discussion. The following questions are included to get you going.

Migration Headache Discussion:
1. Identify the possible causes of the Brant's population decline from year to year.

2. Discuss what kinds of things can and should be done to protect and restore habitats for migrating bird populations. What are the potential trade-offs? What kinds of wetland conservation program do your area/estuary have?

Telecommunications:
Write a paragraph or two discussing the above issues in your area and send it to the listserve.

Journal Use:
Write about some of the above issues in your journal

Adapted from: Aquatic Project WILD. Western Regional Environmental Education Council. 1987.

Migratory Mapping

Subject:
science, social studies
Duration:
one class period
Group size:
groups of 3 or 4
Setting:
inside
Topics:
migration, geography, bird banding

Objectives:
1. Students will be able to map the migration route of the Brant on both the Pacific and the Atlantic flyways based on band and leg band recovery reports.

2. Students will be able to define the terms "wintering grounds" and "breeding grounds", and list two uses of band reports.

Students analyze information from band and leg band recovery reports. With this data they chart both the Pacific and Atlantic flyways used by the Brant.

What is the Pacific Flyway?
Flyways are generalized migration pathways. There are four of these flyways in North America which run north to south. The Pacific Flyway, used by the Brant, is the westernmost flyway. From bird band returns biologists have discovered that during spring migration birds make more stopovers as they follow improving weather northward. In fall the birds wait and move south all at once to good weather.

Why Band Brant?
Banding of Brant is done to provide information regarding their migratory routes. Through recovery of bird bands, data on direction and duration of migration is obtained. Sightings of live tagged birds and retrieval of dead bird tags provide additional information about birds' use of migration areas and provides indications of survival rates and life spans.

Who Uses the Information?
The U.S. Fish and Wildlife Service Bird Banding Laboratory in Maryland maintains a record of all bird bands in the United States. All researchers must obtain permits from the Bird Banding Laboratory in order to embark on a bird marking project. Marked birds must have, at a minimum, a silver colored U.S. Fish and Wildlife band with an 8 or 9 digit number. This number and all information about the bird- such as sex, age, weight, condition, date, and place of banding- are on file at the Bird Banding Laboratory.

Why Use Colored Tags?
Quite often researchers will also tag another part of a bird. This extra tag is usually colored and has a combination of letters and numbers that identify that bird in the biologists' study. Some of the colored tags have larger, more distinct codes that may be read from a distance. If a biologist wants a goose to be distinct, he or she may add a colored collar with a code such as "8Y3" in large print. Colors are assigned to specific breeding areas

What Should You Do if You Find a Banded Bird?
If you find a banded bird and can read any or all of the numbers on the bands or the leg band collar, you should contact the U.S. Fish and Wildlife Service and they will forward the information to the Bird Banding Laboratory. The laboratory staff will look up the numbers and contact the biologists who conducted the study. The biologists will then use the information that you gave them about the circumstances in which you saw the bird in their studies. The laboratory will also let you know when and where the bird was banded.

How do Brant Migrate?
Brant migrate in strings, v’s, and often in less organized flocks. They can, with a good tailwind, reach speeds up to 65 mph. Their migration on the Pacific Flyway follows the movements of the seasons. In general, the Brant's migration is as follows:

Location Arrival/Departure

Reason
Mexico Oct-Nov/Mar-Apr

wintering grounds
California Mar-Apr/Apr-May

staging grounds
Oregon Mar-Apr/Apr-May staging grounds
Washington Mar-Apr/Apr-May staging grounds
B.C. Mar-Apr/Apr-May staging grounds
Alaska Apr-May/Aug-Sept nesting grounds
N. Canada Apr-May/Aug-Sept nesting grounds
Russia Apr-May/Aug-Sept nesting grounds
Izembek, AK Aug-Sept/Oct-Nov

feeding grounds
Izembek, AK spring/fall

staging/wintering areas

Materials:

Procedure:
1. There are 10 Brant reports included with this activity. The reports are simplified versions of actual data that have been turned into the U.S. Fish and Wildlife Service. There are two ways to do this activity:

a. Younger students: While students follow along on their own maps, plot the band reports on a large map at the front of the classroom. See the following procedures for more detailed instructions.

b. Older students: Have the students break into groups of three or four and plot the Brants' use of the Pacific and Atlantic flyways. Make as many copies of each set of band reports as you'll need for the groups.

NOTE: If possible, have a U.S. Fish and Wildlife Service employee bring in samples of actual bird bands and/or mounted birds with bands to discuss banding in greater detail. Have the speaker tell students why banding is done, and what they should do if they see a band on a bird (either alive or dead).

2. Introduce students to the idea of flyways.

3. Hand out copies of the North American maps to each student. Each map should have all of the states, Mexico, Siberia and Canada.

4. Tell students that they are wildlife biologists compiling Brant recovery data. The reports include color tarsus band numbers and leg band observations that people have given to wildlife biologists so that they can track where the Brant have been. Each report gives the following information:

5. It is the students' job to mark these data points on the map as follows:

6. If time remains, have each group use the string and push pin method for the large classroom map, to designate the Brant banding reports found.

MIGRATION MAPPING DISCUSSION QUESTIONS:
1. Where are Brant normally banded and when? (Brant are usually banded in their nesting areas while they're molting and can be easily captured)

2. How many different ways are reports of banded birds obtained? (e.g., shot by hunters, seeing marked birds, finding dead birds, etc.)

3. Discuss what people can learn from band returns and information about Brant migration. (Returns tell us where important feeding and resting areas are so that they can be protected, where and how many birds are taken by hunters so that the harvest can be regulated to maintain healthy populations, how much energy birds need, how long birds live, etc.)

Adapted from: Issue Pac. "Hunting and Wildlife Management." U.S. Fish and Wildlife Service.

Pacific Brant Reports

These reports were obtained with the help of Bird Banding Laboratory in Maryland.

1. A banded bird was found dead on the shore of Puget Sound in western Washington state on April 29, 1984.
FILE DATA: Banded July 11, 1963 near Hooper Bay on the west coast of Alaska when it was one year old.

2. A previously banded bird was caught and released by a U.S. Fish and Wildlife employee on July 20, 1978 near Cold Bay, Alaska.
FILE DATA: Bird was banded in northern California on April 12, 1976.

3, 4, and 5. Whale-watchers in Baja California (Mexico) saw a flock of Brant in Scammon's Lagoon in west central Baja on January 15, 1990. Three birds had yellow leg bands.
FILE DATA: Biologists put yellow leg bands on 300 Brant near Hooper Bay on the west coast of Alaska in July, 1989.

6. A hunter shot a banded Brant on February 10, 1958 in Northern California.
FILE DATA: On March 17, 1953, this goose was banded in California.

7. A single band was found by a bird watcher on February 6, 1980 off the southern coast of California.
FILE DATA: This particular goose was banded on May 18, 1966 near where the band was actually found.

8. While hunting at Cold Bay on the Alaska Peninsula, a hunter from Anchorage shot a Brant with a blue leg band on October 20, 1990.
FILE DATA: Blue bands were put on 50 Brant on Banks Island (northwest of the mainland in the Northwest Territories) on July 20, 1989.

9. A British Columbia hunter shot a banded Brant near the border between Washington and Canada at Boundary Bay on March 2, 1988.
FILE DATA: Banded July 13, 1963 near Hooper Bay on the west coast of Alaska.

10. While boating off the coast Ensenada, Baja, Mexico, a local family identified the leg band of a Brant on January 21, 1990.
FILE DATA: On July 20, 1978, Brant geese were banded in Alaska.

11. A bird watcher in Coos Bay, Oregon sighted the following: a group of 223 Brant, 2 of which had bands that could be read. This occurred on February 23, 1998.
FILE DATA: One was banded on July 1989 near Hooper Bay in Western Alaska. The other was captured and banded near Teshekpuk Lake in northern Alaska in July 1991. He was also seen wintering in Mexico in 1992 and 1993.