Bald Eagle Migration Update: February 12, 2003

Today's Report Includes:

• New Eagle Now Online! Peter Nye's Journal
• Challenge Question #3
• First Winter Range Map and Satellite Data
• Why Count Manatees, Monarchs and Eagles in Jan.? Discussion of Challenge Question #1
• Why Migrate? Discussion of Challenge Question #2
• Teacher Tips: Building Students’ Vocabulary With Journey North
• Instructional Strategy Spotlight: "Lead Preview"

Eagle V31 with Peter Nye and Kathy Michell Photo: Gene Weinstein

• Link to Eagle V31’s Capture Story

Reading Peter Nye’s journal is second best to spending the day in the field with him. There’s so much to learn!

Challenge Question #3:
"If you knew nothing about bald eagles, how many new facts about eagles could you find in Peter Nye’s story? Include your list of facts with your answer."

(To respond to this question, please follow the instructions below.)

Photos of the capture process from a previous year.
Eagles at deer carcass	Rocket net	Deployed! Was an eagle captured?

What do you suppose "winter range" means? In our February 19th update we'll discuss the term. Meanwhile, think about that while you plot the latest satellite data from each eagle on your map (or print and analyze our map).

Link to Latest Data:

• Eagle #E47
• Eagle #E49
• Eagle #E50
• Eagle #E63
• Eagle #V31
• Golden Eagle #A20

"I think January is the best time to count manatees, monarchs, and bald eagles because they're all in one place and not really moving around much before migration," replied Megan of St. Wendelin High School.

Exactly! The reason, in a single word, is COLD. Cold causes manatees, monarchs and bald eagles to congregate (group together). This makes counting them much easier for biologists! It's interesting to compare and contrast the reasons each species congregates:

• Manatees are very sensitive to cold. Biologists try to schedule their surveys for the coldest days, when the manatees gather at their favorite warm water spots (such as Blue Springs State Park).
• Monarch butterflies from across eastern North America gather in one tiny region of Mexico for the winter. They form their tightest aggregations in January. Biologists count the butterflies when they’re packed together tightly, and too cold to fly.
• Bald eagles congregate in areas where food is available, especially around open water where they can find fish and waterfowl. ("Open water" refers to those portions of lakes, rivers, and streams that are not covered with ice.) Peter Nye trapped Eagle V31 in such an area, which is why a dozen other eagles came to the bait.

Congratulations to Mike, Chris, Lisette and Kriten of Iselen Middle School in New Jersey for trying this very difficult question. They knew the answer must be related to food, and understood that food would be available in the north.

"Eagles only migrate when they need food… When they go back to the North, there will be more food for them. The cycle then repeats itself."

Peter Nye thinks about it this way:

If the eagles all decided to stay where they wintered, things would get pretty crowded in a hurry! So even though there is food available in New York in the summer--and some eagles do stay--others migrate north. The eagles that migrate north will take advantage of a rich, though temporary, food resource. Only during summer months is food abundant in the far north, and readily available to bald eagles. When fall and winter come, they must migrate south to survive.

How do the eagles know to go north in the spring? Peter Nye explains:

"Bald eagles have an inborn tradition to their general area of fledging, called 'fidelity,' which draws them back there. This instinct has probably evolved over thousands of years. The rationale behind nest-site fidelity is that since eagles were successfully born in a certain area, the chances of their success at nesting in the same general area are probably pretty high."

New! Reading and Writing Connections

• Teacher Tip: Building Students’ Vocabulary With Journey North

• From: Forty Best Instructional Strategies

1. Address an e-mail message to: jn-challenge-eagle@learner.org
2. In the Subject Line of your message write: Challenge Question #3
3. In the body of EACH message, answer ONE of the questions above.

The Next Bald Eagle Migration Update Will Be Posted on February 19, 2003