Eastern Bald Eagle Migration Update: February 22, 2000 Today's Report Includes:
Field Notes from Biologist Peter Nye Home on the Winter Range This is just what we expect, especially from older birds. But Eagle #F81 has not exhibited the same fidelity to his wintering area as the other birds have. It may be that he is a young and unattached male. Perhaps he's still kind of floating around, trying out different areas, and has not yet settled on a 'permanent' wintering site. (Or breeding site for that matter. If you study his spring/summer 1999 movements, those also look like a young, unmated bird without a definitive breeding territory yet. The locations are not in a tight cluster like many of the others. Rather, they're scattered over time and range.) Discussion of Challenge Question #1 "By the way, Eagle #K70 was captured in the St. Lawrence River on Wellesley Island, which is one of the larger Thousand Islands. So all the students who figured 'Thousand Islands' had a pretty good answer! She has been staying very local to the capture area except for her minor southern junket to the interior on 2/16. It'll be interesting to see how long she stays around there. Likely just a short 'visit', then back to the river. We'll see. Research Goals: Information for Protecting Eagle Habitat ![]() ![]() "And finally, because we have satellite radios that can operate for multiple years, we are learning about "fidelity" to these sites and routes. That is, how faithfully do these eagles use their wintering areas, migratory routes and nesting areas year after year? Nye's Surprises About Fall Migration Discussion of Challenge Questions #2 and #3 "Challenge Question #2 asked, What did you learn about 'fall migration' that surprised you the most? "I expected these birds to come back down to their wintering areas as in the past, more based upon calendar timing (amount of daylight) than anything else. This they didn't do. As you know, Eagle #F81 didn't complete his "journey south" until last week. Eagle #F43 arrived back in NY on 8 January in 1999, but not until the 21 January this year. Other adult eagles begin arriving back in New York in November and December--so there is quite a range in their arrival dates overall. "Why do some birds travel at different times than others? We don't yet have all the answers! I suspect much is related to: where they are coming from; the amount of open water (and thus fish and the eagle's ability to survive); if the winter is very mild, as ours was here in the East until mid-January, travel dates will be affected. In such situations, the eagles are under no pressure to move south. ![]() "Challenge Question #3 asked, What good news does the data suggest about the population survey in NY on Jan. 15? "Did you notice that our population survey took place before #F43 and #F81 returned to New York?! Without satellite tracking, we never would have known. This says two things: 1. We undercount the numbers of wintering eagles using New York, and 2. Our ever-growing wintering population is partially a result of our own success in reestablishing breeders. As our breeding population grows, and as they fledge more and more young each year, those birds are adding to our wintering population. (For those interested in graphing the increase in eagle numbers from 1980 to 2000 see: ) ![]() Eagleye Nye New York State Dept. Environmental Conservation Delmar, NY You're the Scientist: Challenge Question #4 Make a "winter range map" for the eagles using the data provide below. (Or print and analyze our map.) Your job is to define each bald eagle's wintering range, and then describe the eagle's behavior within that range. Try to write the best verbal description you can. To get started, look at your map and answer this question:
(To respond to this question, please follow the instructions below.) Human Home Range To put these eagles' travels in perspective, compare them to your own travels. In the past 3 weeks, what is the greatest distance between two places you have visited? Calculate the furthest distance between points within your winter range, then answer this question:
(To respond to this question, please follow the instructions below.) Are YOU Ready for the Migration? Lessons to Hone Your Skills
How to Respond to Today's Challenge Questions Please 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 #4 (or Challenge Question #5) 3. In the body of EACH message, answer ONE of the questions above. The Next Bald Eagle Migration Update Will be Posted on March 7, 2000. Copyright 2000 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form
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