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Bald Eagle Migration Update: April 2, 2002
Today's Report Includes:
- Field Notes from Peter Nye
- What's GMT (Greenwich Mean Time)?
- Challenge Questions #13 and #14
- Spring 2002 So Far: Comparisons to Last Spring's Departure Dates
- When Nobody's Looking: Discussion of Challenge Question #11
- High, High Tech: Discussion of Challenge Question #12
- Up, Up and Away: From Skyscrapers to Outer Space
- Answers from the Eagle Expert
Field Notes from Peter Nye
Lots of movement to report now!
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The highlights:
- Whoa! K58 has bolted!! In just 3 days, she traveled from the New York/Vermont border to Prince Edward Island
- E47 is on the move!! And this is kind of interesting. We caught E47 in flight on Thursday. The first reading was at 17:28 GMT (Greenwich Mean Time) and the second at 22:49 GMT. Those readings are 5 hours and 21 minutes apart. How far did she move in that time??
- E63 left NY as of March 27! Just a couple days later than last year...and was still moving as of the 29th.
- K70 may now be on the move...She has crossed into Canada.
- Perhaps March 30 is the start of a north-move for E50?? Early to tell, but as of that date he's about 30 miles north of his former locations.
- E49 dropped back south about 60-70 miles between 3/25 and 3/27. What's the name of the river she's near-and why might she have moved south?
Until next week,
Peter Nye
New York State Dept. Environmental Conservation
What's GMT (Greenwich Mean Time)?
Greenwich Mean Time (GMT) is an international time-keeping standard. It is based on the local time in Greenwich, England. Greenwich Mean Time is also called Universal Time (UT). When measuring time with GMT or UT, it's the same time everywhere on earth! That's why it's considered "universal time." You can think of it as a way to specify an exact moment --the concept of RIGHT NOW--everywhere on Earth. GMT was invented to avoid the confusion that using "local time" causes when referring to events taking place in different time zones.
The satellite gives times to scientists according to GMT or Universal Time. Remember, the satellite is zooming around the earth every 101 minutes, so local times on Earth are a blur.
So what time IS it where the eagles are, local time? After all, local time DOES matter to an eagle whose behavior is regulated by earth's day/night cycles. Because the eagles are in the Eastern Time Zone, they are 5 time zones to the west of Greenwich, England. This means that local time for our eagles is 5 hours EARLIER than Greenwich Mean Time.
Challenge Questions #13 and #14
Challenge Question #13:
"How far did E47 move in the 5 hours and 21 minutes between her two March 28 readings? What time was the eagle migrating (local time)?"
Challenge Question #14:
"How many miles did Eagle K58 travel within 3 days, between March 21 and 24?"
(To respond to these questions, please follow
the instructions below.)
By the way, you can collect these answers as "migration facts." Just think: Before satellite tracking
none of this information could have been known!
Spring 2002 So Far...
| Eagle | Spring 2001 | Spring 2002 |
| E47 | March 14 | March 26 |
| E49 | March 18 | March 16 |
| E50 | April 5 | March 30? |
| E63 | March 24* | March 27* |
| K58 | March 20 | March 24 |
| K70 | March 30 | March 29 |
| K72 | April 2 | Not yet.... |
For your chosen eagle, compare other migration variables such as length of migration, distance to nest, date of arrival at nest, possible male/female differences, etc.
When Nobody's Looking
Discussion of Challenge Question #11
It's a rare chance to receive two good readings within a few hours of each other-and to catch an eagle during migration! In our last report, we reminded you that ONLY when we receive readings can we show a location on the migration map. What might be happening when the satellite's not looking?
"I think the eagle is a lot busier than the map shows," says Lane of Ferrisburgh Central School in Ferrisburgh, VT. Here are some of Lane's and our examples:
- The eagle might be building a nest and so would have to go back and forth a lot for sticks.
- The eagle is probably hunting for food. The eagle would be flying in fields, forests, and lakes looking for rabbits, rats, and fish.
- The eagle might be looking for a mate.
- The eagle might not fly in a straight path between two dots; we can't know the actual path of migration.
- The eagle might--or might not--be stopping where we see dots. When we plot a location, the eagle might be flying overhead or might be on the ground. (This means the eagle may--or may not--depend on safe habitat at each dot.)
- The dates of each location don't tell us when the eagle LEFT the previous location, only that the eagle HAD LEFT by the date of the location.
- The eagle might not be really wearing the transmitter at all! Occasionally transmitters do fall off. The scientist must always keep this possibility in mind, especially when the readings indicate the eagle is in one place.
High, High Tech
Discussion of Challenge Question #12
We asked, "How many miles above the earth do the polar-orbiting satellites travel?"
Amazingly, the satellites travel 833 km above the earth, which is equal to 517 miles!
Up, Up and Away: From Skyscrapers to Outer Space
Let's put this into perspective. How high are satellites, clouds, and the world's tallest trees and buildings? How high do jets, hot air balloons, migrating birds and butterflies fly? On the highest wall you can find, make a model of the earth's atmosphere to scale. Using altitudes provided on the list below, start on the ground and go to the edge of outer space. This lesson provides great practice for converting from English to Metric measurements, too.
Answers from the Eagle Expert
Special thanks to Peter Nye who answered these questions so thoroughly even though home sick!
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 #.
3. In the body of EACH message, answer ONE of the questions above.
The Next Bald Eagle Migration Update Will Be Posted on
April 9, 2002
Copyright 2002 Journey North. All Rights Reserved.
Please send all questions, comments, and suggestions to our feedback form
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