Bald Eagle

Bald Eagle

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Bald Eagle Migration Update: April 7, 2004

Today's Report Includes:

Eagles Headed for Northern Newfoundland
While our new Bald eagle, V98 hasn’t moved much from his location in the Adirondacks, the Golden eagles appear to have cranked up their migration to reach familiar territory in the north. Will V98 migrate further north, too? Take some time to study this week’s data and map.
Field Notes from Peter Nye

Happy April Eagle Students!
Eagle dDedicated to keeping eggs warm in the snow.
credit Eagles Online

Yes, April is finally here and most of our New York resident breeding eagles are now sitting on eggs. April is always a tough month for early-nesting birds. Last year, we had major snow and ice storms the first week of April, resulting in the loss of many nesting attempts (eggs that failed to hatch), due to the foul weather. So far this first week of April, we had up to 3 inches of rain over a two-day period here, and last night (4 April) we had snow and winds up to 50 miles per hour. This morning at my house it was 19 degrees Fahrenheit with wind-chill about 0. Again, this can be tough on birds trying to incubate eggs and keep them at a constant temperature of about 99 degrees F. If such "nasty-weather" bouts are of short duration, the incubating adults usually have no problems getting through them.

Anyway, back to our migrating birds.

Our new bald eagle V98 continues to hang around Long Lake in our Adirondacks. What does this mean? Does this now tell us she is nesting up there? It may require a little work, but you might be able to search the archives over the years and see what the latest date was that any of our migrant bald eagles were still within New York State.

I'm not ready to make a judgment yet! You be the investigator. What did you find?

A Closer Look at Golden Eagle A20
Golden eagle A20 is probably going to “settle in” this year. You’re your eye on him. Captured Feb. 16, 2002 when he was a juvenile, A20 is now showing more of the behaviors of an adult. This means he might be performing new rituals this spring – looking for a mate and building a nest.
Eagleye Continues...
Golden eagle A20 has continued it's move, and is now up in Quebec Province, north of where it was last week. From last year’s data on this bird, I would suspect it won't stay there long, and will continue on north, towards the area that A00 now occupies.

Golden eagles A00 and A20 appear to be on the same migration path as last year. Take a look at the 2003 and 2004 maps next to each other. Where was A20 exactly one year ago? How do the 2 maps compare? Do you agree with Eagleye that A20 is heading north to where A00 is now located?
Study and Compare Locations of A20
April 9, 2003
April 7, 2004

Have a great Easter Holiday everyone!

Eagleye
Endangered Species Unit
Wildlife Diversity Group
Endangered Species Unit
Delmar, NY

Cold Weather Nesting
Incubating eggs is a major job for eagles. As we witnessed earlier this spring, eagle parents often sit through some snowy winter-like conditions to keep their eggs warm and safe. They are a lot like our official Mail carriers whose dogged persistence to deliver the mail when “neither snow nor hail nor sleet nor storm” will stop them! This dedicated job continues for a long time; eagle eggs require an incubation that lasts about 35 days.

Eagles Online has a Web camera poised over a Bald eagle nest in MA. The nest contains 2 eggs laid on March 8, and 11.

Challenge Question # 20:
“When do you predict each of the eggs in the Eagles Online Webcam nest will hatch?”

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

Keep your eye on their nest and maybe you’ll witness the eggs hatching! You can view up-to-the-minute still pictures of the current day on the Gallery page, or if you have a fast internet connection, you can even view the streaming video directly from the nest! Watch the way the eagles are behaving in the nest and keep a list of all the behaviors you notice during this crucial time in their life cycle.

Comparing Incubation Times: Is there a Pattern?
Study the list of each bird's egg-incubation period. Put them into order from longest to shortest. Put them in order by size of the bird. How else could you organize them? Can you predict a pattern in nature for incubation times?
What about your favorite bird species? Predict how long they require incubation then do some research and find out if you were correct.
Bald Eagle 35 days
Great Horned Owl 28-30 days
Eastern Bluebird 12-18 days
American Robin 12-14 days
Downy Woodpecker 11-12 days
Ruby-throated Hummingbird 16 days
Red-winged Blackbird 11 days
Belted Kingfisher 22-26 days
American Goldfinch 12-14 days
New Light Shed on Transmitters: Discussing CQ #19
Last week Peter Nye shared the news that his team was going to be using some solar-powered satellite transmitters this spring for tracking eagles. We wondered what kinds of problems might be encountered with this kind of devise and you provided some thoughtful ideas.
First Graders Paige, Erik and Hannah from Ferrisburgh Central School wrote this: “If something covered the battery, like feathers or dirt the battery wouldn't be able to get sunlight to charge. If it was a dark or cloudy day, the battery would also not charge. We have solar powered battery calculators in our room. If the battery solar panel is covered, the calculator doesn't work. If the room is too dark, it doesn't work."

At Iselin Middle School Seventh Graders Mike W., Robert M., Chris C., and Moaz did some creative brainstorming, and so did Tom, Heather, Kristina and Matt. Here is what they thought:
“One problem that eagles run into with solar power transmitters during the cold winters of New York, may be that there is not much sunlight. This would mean that the transmitter won't recharge the battery.” Other ideas include:
  • Lack of sunlight
  • Out of range
  • It might fall off
  • It could get damaged when landing
  • Rust
  • Bad weather

Thanks for your ideas.

Solar Powered Transmitter: Some Details
Solar PTT
credit Microwave Telemetry
No new data on bald eagle E50 this week and we suspect that the 3-year old transmitter has most certainly quit now. The new solar transmitters that will be tried this spring on some of the nestling eagles are made by a company called Microwave Telemetry. This solar unit has some really neat features. The little solar panels are capable of charging the internal batteries even in poorer light conditions. The solar duty cycle timer takes care of the battery charge control and commands the PTT to either transmit continuously or on a 1/3 ON duty cycle (to qualify its use under the Argos "limited use" category) dependent on the state of charge of the battery. Three hours of exposure to a bright sky is enough to power the PTT for 24 hours.
Light for Flight: But How Much do Satellite Transmitters Weigh?
TrappingMarch2003_048
Have you ever wondered about the effect the satellite transmitters might have on the eagles?
As you can see from this picture (on Web), the transmitter is worn on the eagle's back--almost like a backpack. These backpacks are known as "PTTs," which is short for "platform transmitter terminals."

Each PTT package weighs approximately 100 grams (3.5 oz.), which is less than 2 percent of the body weight of an average bald eagle.

How would it feel to carry such a backpack?

Challenge Question #21:
“If you wore a backpack that weighed 2% of your body weight, how heavy would your backpack be?”

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

Satellite Transmitter Backpack Style Show
TrappingMarch2003_058
The eagle's wings are extended and the transmitter goes on its back.
An eagle wearing a satellite transmitter is hard to imagine for most of us. Do they wear it on their belly or on their back? How is it attached? Can it easily be damaged or fall off? Does it slow down the eagle that wears it?

Last year Elizabeth Howard and Peter Nye set up their fashion camera to show you how the transmitter is fit to the eagle. You’ll see the ingenious system that has been developed to provide the best transmission possible with the least amount of stress to the bird. Take a look!
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 #20 (or #21).
3. In the body of EACH message, answer ONE of the questions above.


The Next Bald Eagle Migration Update Will Be Posted on April 14, 2004.

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