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A/CPB
Bald Eagle Migration Update: February 9, 1998
Bald Eagle Migration Updates Will be Posted on MONDAYS:
Feb. 9, 23, Mar. 9, 23, Apr. 6, 20, May 4, 18
Today's Report Contains
- Suggestions for Student Research Using Satellite Data
- An Introduction From Our EASTERN Bald Eagle Scientist (Peter Nye, New York)
- Today's Satellite Migration Data from EASTERN EAGLES
- Challenge Question #1
- An Introduction From Our WESTERN Bald Eagle Scientist (Jim Watson, Washington)
- Today's Satellite Migration Data from WESTERN EAGLES
- Challenge Question #2
Suggestions for Student Research With Satellite Data
The migration data that will arrive from our two eagle biologists this spring provides an opportunity for you to do your own research. Read the objectives of each scientist's study in today's report. Then consider how you might design a study of your own using the same migration data. Make a hypothesis, then compare and contrast the data from each migration. For example, you may look for similarities and differences between:
Eagles Wintering in the West vs. East
How do you think eagle migration in the different regions will compare? Predict the timing and destination of each eagles' migration. What factors do you think might make them different and/or similar?
Migration Behavior from One Year to the Next
Do you think an eagle follows the same route every year? Do you think the timing of the migration is similar from year to year? As Spring, 1998 data is provided for Western Eagles #05 & #16, their Spring, 1997 data will be provided for the same dates. (Because we don't want to reveal their destinations ahead of time, we are saving last spring's data until the same date this year.) Also, if the batteries in the transmitters of Nye's eagles N98 and N99 last through this spring's migration, you may also compare these birds' spring migrations over 2 years.
Spring Migration vs. Fall Migrations
Do eagles take the same routes in the spring and fall? (Fall migration data won't be provided until after the eagles reach their nests this spring. Again, we don't want to spoil the surprise!)
Migration Behavior of Adults vs. Juveniles
Would you expect the migration of a breeding adult to be the same as that of a juvenile eagle? Why or why not?
Compare the movements of Nye's juvenile #N99 with that of a breeding adult this spring.
Migration Behavior of Females vs. Males
Would you expect the migrations of males and females to be the same or different? Why? What can you learn from
Watson's males (#16 & # 13) and females (#05 & #12)?
At the conclusion of your study, write a scientific paper. See Lesson:
Scientist Says: How Scientists Communicate the Results of Their Research
Meet This Year's Eagle Biologists:
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Jim Watson of |
Peter Nye of New York Department of Environmental Conservation |
Introduction From Our EASTERN Bald Eagle Scientist
Peter Nye, New York
"Hello students- glad to be back on-line with those of you who have followed our eagle progress before, and
also to those of you who are new to this; a hearty welcome to you all!
"Since early December, when eagles typically begin arriving here from
their northern (Canadian) breeding grounds, we've been deeply involved in our ongoing winter-bald eagle monitoring
and research. Our objectives continue to be primarily two-fold with this work:
- Identification of local movements and critical habitat areas (ie roost sites, nesting sites, feeding and concentration areas); and, long distance movements and
- Timing (migration routes, departure dates and duration of migration, ultimate nesting sites).
"We successfully captured and radio-tagged our first eagle on December 16, #F42 She's a big, beautiful
adult female and was captured along the lower Hudson River near West Point. (See if you can find it.) In addition
to her leg bands and radio transmitters, we collected a small blood sample to test for contaminants. (See more
about these contaminants below.) F42 has been staying very local within the Lower Hudson River area, confirming
for us some previously known night-roosting sites. She is being tracked nearly daily by our technicians from the
ground.
"We anticipate putting out at least two more satellite radio units this
winter, perhaps more. Early March is a particularly good month, as many
eagles are moving through and around the state at that time in or preparing
for migration north. At that time we will also activate a capture station at
Upper Saranac Lake in northern NY in our Adirondacks, a place that seems to draw in migrating birds moving north,
when there is a nice, fresh deer carcass on the ice. So....., stay tuned! Many weeks of winter lie ahead!
"The winter of 1997-98 in New York has been very mild so far, with
greater than average amounts of rainfall and less than average amounts of snow and ice. These are conditions not
conducive to "concentrating" eagles and limiting their food supply. Consequently it's been more difficult
to capture eagles this year than during severe winters. Although this has hampered our trapping efforts somewhat
so far, we are still optimistic and there is much winter left. (Despite the extensive amounts of open water, we
also have good numbers of eagles in the state. Our mid-winter survey of the southeastern portion of NY on 12 January
was a record since 1979 of 125 eagles.)
"We recognize 5 bald eagle wintering areas in New York, and have been involved in monitoring and research
in all of them to one degree or another since 1976. Our efforts and focus have shifted as we have learned something
about eagles in each place. Our Upper Delaware wintering area in the southeastern part of NY, our largest, has
been under study the longest, and we know the most about this area. We've captured, marked and followed over 60
bald eagles in this area.
"About 4 years ago we began to study our second largest wintering population in northern NY along the St.
Lawrence River. We have captured about 10 eagles here, including N98 last winter. (On WWW, Nye summarizes the travels
of last year's eagles, N98 and N99.)
"What used to be our 3rd largest population, along the lower Hudson River (#F42's 'winter home'), has been
'growing' in eagle numbers over the past several years, and now is likely tied with or larger than the St. Lawrence
population; 30-40 eagles overwinter in the Hudson area now. Because of its growing importance and because of potential
problems with chemical contaminants (primarily PCB's), our attention has shifted to this lower Hudson area, and
much effort will occur there this winter. However, we will also be conducting capture and tracking efforts along
the St. Lawrence again this winter, as well as along the Upper Hudson
River.
More next time,
Eagle Eye Nye
New York Department of Environmental Conservation
Today's Satellite Migration Data from EASTERN EAGLES
* Important Note
Data from these eagles will only be provided as long as the batteries in their transmitters last, which Nye estimates
may be only through February. However, while it lasts, the data provide an excellent opportunity to compare the
birds' behavior in 1997 vs. 1998, as well as the behavior of an immature vs. breeding individual.
Challenge Question #1
Migration data from Peter Nye's three eagles is provided above. Review the data and see if you can answer this question:
Challenge Question #1
After receiving data about Eagle N99 on what date did Nye say: "It looks like our immature from last winter, N99, has moved back south finally and is now on Lake Ontario just south of Amherst Is (Ontario)."
(To respond to this Challenge Question, please follow the instructions
at
the end of this report.)
Introduction From Our WESTERN Bald Eagle Scientist
Jim Watson, Washington Department of Fish and Wildlife
We welcome Jim Watson to Journey North this season! Based in Washington State, he will be sending data from 4 eagles who are presently over-wintering there. Because 2 of these 4 birds were captured last spring, you will be able compare migration data of the same birds over 2 years. The batteries of these transmitters will last through the winter of 1999. (Due to space considerations, however, we will provide the Spring, 1997 data on the WWW only.)
"Dear Students,
"I am conducting a wintering study of bald eagles on Washington's Skagit River. This river, and its tributaries, support up to 500 eagles that feed on chum salmon from November through February. These salmon spawn on the upper river and their carcasses wash onto gravel bars where the eagles congregate to feed.
"During the same time, recreationists congregate on the river to fish for steelhead (a large rainbow trout) and watch the eagles. Because of potential concerns for disturbance of the eagles from these activities, the U.S. Fish and Wildlife Service, Forest Service, and Department are funding a study to determine where these eagles come from, how long they survive, and if their nesting populations are healthy.
"The research began in 1996, and will continue for at least 3 more years. To determine where the eagles come from, we are using satellite telemetry that allows me to retrieve the locations of the eagles right from my computer--within an hour or two of sending a signal, I can tell where the eagles are several hundred kilometers away! There are also small VHF transmitters on the eagles that allow us to follow them on the river or locate them if they should die.
"As always, my wife and sons, 12-year old Cory, and
10-year old Jesse, often assist me on the study (see photo). Its hard to believe that these "fledgling scientists"
are at the age when I was 25 years ago when I became interested in raptors--perhaps someday they will be 'fully-fledged'
raptor scientists! "Trapping has been considerably more difficult this year (milder weather; and because the birds are somewhat stationary we are working with the same birds so they get trap shy pretty fast). I had anticipated that trapping would get more difficult in January when fewer carcasses and fewer birds are on the river. But we've met with outstanding trapping success during January. We have a total of 34 birds for the study, of these 17 are with transmitters."
Jim Watson
Washington Department of Fish and Wildlife
Today's Satellite Migration Data from WESTERN EAGLES
Challenge Question #2
One of the eagle's movements surprised Jim Watson and caused him to say: "One of the recent captures is
now in _____ . This is a new movement pattern for all birds captured thus far."
Challenge Question #2
To which eagle's do you think Jim Watson is referring? Where did the eagle go? (Give the eagle's number in your answer.)
How to Respond to Today's Challenge Questions
How to Respond to Journey North Bald Eagle Challenge Question # 1
1. Address an e-mail message to: jn-challenge-eagle@learner.org
2. In the Subject Line of your message write: Challenge Question # 1
3. In the body of the message, give your answer to this question:
Challenge Question #1
After receiving data about Eagle N99, on what date did Nye say: "It looks like our immature from last winter, N99, has moved back south finally and is now on Lake Ontario just south of Amherst Is (Ontario)."
How to Respond to Journey North Bald Eagle Challenge Question # 2
1. Address an e-mail message to: jn-challenge-eagle@learner.org
2. In the Subject Line of your message write: Challenge Question # 2
3. In the body of the message, give your answer to Question #2 above.
The Next Bald Eagle Migration Update will Be Posted on February 23, 1998.