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Bald Eagle Migration Update: February 26, 2003
Today's Report Includes:
- Latest Map and Satellite Data
- Frozen Dinners: The Challenge of Finding Food in Winter
- Challenge Questions #6 and #7
- Try This! Scavenger Hunt for Eagle Food
- Predator and Prey: Generalist or Specialist?
- Discussion of Challenge Question #4: You’re the Scientist
- Discussion of Challenge Question #5: Human Home Range
- Instructional Strategy Spotlight: Mark Up the Text
- Now Open! Ask the Bald Eagle Expert
Latest Map and Satellite Data
Here’s the latest winter range map. How much have the eagles moved since we caught up with them last week? When do you think spring migration will begin?
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Link to Latest Data:
Frozen Dinners
The Challenge of Finding Food in Winter
It has been a cold winter for Peter Nye’s eagles. These temperature maps show “departure from normal temperatures.” Find New York. How many degrees colder than normal was it for Nye’s eagles during the past two weeks?
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| February 8-15 | February 16-22 |
What do eagles eat in the winter time, when rivers and lakes freeze over?
Fish is the bald eagle's favorite food. But when fish isn’t available,
they’ll often shift to such delicacies as road-killed deer carcasses.
“Imagine eating frozen meat without using your teeth.That’s something Bald Eagles do often in the winter. We humans are lucky.Like other mammals, we have teeth. Birds don't.So how can they possibly eat rock-hard, frozen meat during a cold spell?” begins ornithologist Laura Erickson.
Challenge Question #6:
“How many different food items can you name that eagles eat in the winter time? What do all of the foods have in common?”Challenge Question #7:
“Other than fishing for fish, what other hunting methods do eagles have?”
(To respond to these questions, please follow the instructions below.)
Try This! Scavenger Hunt for Eagle Food
Write a list of eagle winter food for the game “Scavenger Hunt.” Which of the items on your list can you find in the space of one day? An eagle eats 5-10% of its body weight each day (250-550 grams of food per day). Do you think you could find that much food on your hunt--enough for yourself or for an eagle?
Predator and Prey: Generalist or Specialist?
Some birds are specialists--this means they must live in a certain habitat, or eat one special kind of food, in order to survive. For example, Snail Kites eat snails; hummingbirds eat flower nectar; osprey catch live fish. If any of these food items disappear, the birds that need them disappear.
In contrast to these birds, bald eagles are generalists. This means they can eat a wider variety of food and live in a wider variety of places. Learn more about generalists and specialists. Many have physical adaptations that are clues to how specialized they are. Take a peek at some bird beaks on this “Generalists or Specialists?” quiz:
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Discussion of Challenge Question #4
You're the Scientist
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"Which bald eagle seems to have the smallest winter range? Which has the largest?" If you were the scientist, we asked what you would have learned from the satellite data so far.
Melissa of St. Wendelin School describes what she’s observed:
“The bald eagle that seems to have the smallest winter range is Eagle 63. It seems to be hanging around the Chesapeake Bay. Eagle 47 seems to have the largest winter range from the end of the Hudson River, all the way up to Lake Champlain.“
Discussion of Challenge Question #5
Human Home Range
We asked, "How does a bald eagle's winter range compare to your own? How much of your home range do you consider to be your territory?"
Alexandra, also of St. Wendelin School, understands the idea of a “territory” perfectly from her own experience:
“I consider 1/8 of my home range to be my territory because there are eight rooms in my house and only one of them belongs to me and the only room I feel necessary to keep intruders out of.”
Technically speaking, anywhere Alexandra travels--to school, a friend’s house, the dentist, etc. are all part of her home range. The “home range” refers to the area in which the animal regularly travels, not only the portion that we humans might consider a house or home.
Instructional Strategy Spotlight: Mark Up the Text
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When students read "Frozen Dinners" to answer today's Challenge Question, have them "mark up the text" as a strategy for careful reading. Explain how to jot "Comprehension Codes" in the margins during reading. For example, as students find examples of eagle foods, a Comprehension Code such as "D" for "Discoveries" could be used.
- From: Forty Best-practices
Instructional Strategies (See "Mark Up the Text")
Now Open! Ask the Bald Eagle Expert
Questions are now being accepted for Bald Eagle Expert Peter Nye. Submit them any time BEFORE the March 7, 2003 deadline at 1 p.m. (Eastern Time).
How to Respond to Today's Challenge Questions:
IMPORTANT: Answer only ONE question in each e-mail message.
1. Address an e-mail message to: jn-challenge-eagle@learner.org
2. In the Subject Line of your message write: Challenge Question #6 (or
#7).
3. In the body of EACH message, answer ONE of the questions above.
The
Next Bald Eagle Migration Update Will Be Posted on March 5, 2003.
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