Bald Eagle Migration Update: April 30, 2003
Today's Report Includes:
Field Notes from Peter Nye
I'm back from a great trip to the southwest. What gorgeous country. We
wondered at the ancient petroglyphs and Indian cliff-dwellings. Also marveled
at the peregrines, golden eagles, condors (many!) and bighorn sheep we
were lucky to see.
Ah, but if only all the work took a vacation also! I’m playing
catch-up now, so here’s the latest migration data:
Link to Latest Data:
and a quick update:
- E50 departed around 4/13, and continues his north-eastward move...
- Think A00 is home? I watch for clustered readings as an indication
of nest location.
I’ll be out in the field most of the next two months. First helicopter
surveys then nest visits.
Eagles Now Nesting Across
Eagleye Nye will be up a tree most days in May and June. He will visit every
eagle nest in the state of New York to band the babies. For our final three
updates this season, we’ll focus on the bald eagle nesting cycle.
In eagle nests across North America the same process is underway. Even though
the timing is different in different climates, the steps take place in the
same order. Here’s an overview:
Visit an Eagle Nest With
“The view from a eagles nest is one of the most spectacular on earth,”
says Pete. “They certainly know how to pick the prime lookout spots.
The nests themselves, once eaglets are born and a few weeks old, are completely
flat across the top, contrary to what you might think of as a 'bowl nest.'
They contain soft vegetation, and often fresh greenery such as white pine
sprigs or some other leaves; cattails and cornstalks are also a big item
here in New York!” For more background information about eagle nests
and activities see:
Eagles Online: The
Eaglet Has Hatched!
On Thursday, April 17 the eaglet hatched in its online nest and is now almost
two weeks old. Let’s watch how it changes during the next two weeks.
What Do You See? What Does
the Ornithologist See?
The three pictures above were taken this week. Record everything you notice
in each picture, and similarities and differences between the pictures.
A Technique for Studying Animal Behavior
How do animals spend their time? Have you ever wondered how scientists find
out? "Ethology" is the study of animal behavior. One way to quantify
behavior is by watching an animal over an extended period and making an
“activity budget.” Basically, an activity budget shows how much
time an animal spends in various activities such as eating, resting, sleeping,
Try This! An Activity Budget for
the Online Eagle Nest
Eagles Online archives photos every 5 minutes and saves them for a full
hour. Use this resource to make an activity budget for a nesting eagle and
eaglet. What behaviors can you observe in the eagle nest? How much time
does an eagle spend at each? (What is impossible to observe, and how would
this affect your results?)
Real Scientific Studies Using
Do a Web search for the phrase “activity budget.” You can read
actual scientific papers (abstract, introduction, methods, results, discussions).
Here are examples:
The macaques spent nearly 70% of the day traveling and foraging, with
the remainder of the time spent resting (20%) and socializing (12%).
The most commonly eaten foods were kapok (32%) and forest fruits (11%),
with crop raiding providing a substantial part of the diet (10%).
Twelve months of cliff-based behaviour sampling accumulated 213 hours
of direct observation on 73 dolphin schools. The overall proportion
of time spent in each of the five behaviour states was: travel (63%),
feed (19%), social (12%), play (3%) and rest (3%), and 90% of all dolphin
activity occurred within 0.25 km of shore.”
Altered time-activity budgets may disrupt the energetic balance of young.
As mercury levels in their blood rise, the amount of time that chicks
spend brooding (by back-riding) decreases and time spent preening increases.
A study of summer and autumn movements of white whales in Norway showed
the whales spent most of their time relatively stationary, close to
different glacier fronts in the area.
These studies are important in a host of ways. For example, scientists
must understand normal animal behavior in order to recognize abnormal
behavior when they see it. These studies are also helpful for conservation
management. Can you see why?
My Activity Budget
How much time do you spend working, playing, resting, sleeping, eating,
learning, obtaining food, etc.? List the behaviors that make up your day,
then measure how much time you spend at each. What patterns do you see?
How does your activity budget reflect what's important in your life? Make
a pie chart to illustrate your results.
Challenge Question #19:
"What percent of your time do you spend sleeping? What takes place
during sleep that is so important?"
(To respond to this question, please follow the instructions
How to Respond to Today's Challenge
1. Address an e-mail message to: email@example.com
2. In the Subject Line of your message write: Challenge Question #19
3. In the body of your message, answer the question above.
Next Bald Eagle Migration Update Will Be Posted on May 9, 2003
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