Loon Migration Update: March 9, 2000 Today's Report Includes: Fly With the Loons? Burning Questions Loon On-Line A Closer Look at Loon #2539's Fall Migration Tracking a Loon: Challenge Questions #3, #4, and #5 Freshwater to Saltwater: Discussion of Challenge Question #1 Photo Quiz: Response to Challenge Question #2 It's Time to Watch for Loons! Fly With the Loons? Wintering and Breeding Range of the Common Loon (Gavia immer) Map by D. Bojar Macalester College Imagine riding on the back of a loon during migration. No one has, of course. So no one knows how far a loon flies in a day, how many times it stops, or what route it travels. These are just a few of many unanswered questions scientists wonder about loon migration. Thanks to Kevin Kenow of the U.S. Geological Survey in LaCrosse, Wisconsin, there's a new chance at discovering some answers. In the fall of 1998, Kevin and co-investigators Michael Meyer, Peter Reaman, David Evers, David Douglas, and Jeff Hines accomplished a historic first. They used radio telemetry to track Common Loons during fall migration. These scientists have generously chosen to share data from one of the radiomarked loons with Journey North so YOU can be among the first to know about this groundbreaking research! It's almost as good as flying with a loon! Burning Questions Imagine you are a scientist studying loon migration. What burning questions would you have? For starters, Kevin said he wondered: "What is the relationship between breeding lakes and staging areas, and between breeding lakes and wintering grounds? How is the timing of migration influenced by weather patterns? What are the habitat requirements of loons during migration? How long does migration from breeding to wintering areas take?" Kevin took advantage of recent technology whereby loons fitted with radio transmitters could be tracked by satellite. Once tagged with a PTT (platform transmitter terminal), a loon can be tracked from a computer using orbiting satellites. Now Kevin's questions have some answers. Meet one loon that helped! Loon On-Line Loon #2539 Meet Loon #2539. Kevin and his co-investigators developed the techniques to radiomark this loon. On August 26, 1998 they fitted the captured loon with a satellite transmitter, or PTT. Then they released it and watched their computers to see what happened. Using the migration data in today's report, you can discover for yourself some things Kevin and his co-investigators learned. A Closer Look at Loon #2539's Fall Migration Using the satellite data Kevin provided (see link below), can you answer the following questions? When did the loon start the migration? When did the loon arrive on the wintering grounds? How many days did it take the loon to travel from Minnesota to the wintering grounds? Satellite Location of Common Loon #2539 Tracking a Loon: Challenge Questions #3, #4, #5 In our next report we'll include a map, and Kevin Kenow will tell us what surprised him the most about Loon #2539's fall migration. Which leads us to ask: Challenge Question #3: "What did you learn about Loon #2539's fall migration that surprised you?" Challenge Question #4: "Where does Loon #2539, which nested in Minnesota, go for the winter?" Challenge Question #5: "Why do you think the transmissions followed the time schedule you see in the data table?" What other questions can you think of as you look at the data? Make a list! (To respond to these questions, follow the instructions below.) Freshwater to Saltwater: Discussion of Challenge Question #1 Loon Salt Glands Photo: Judith McIntyre in The Common Loon, Spirit of Northern Lakes Because loons migrate between freshwater lakes and saltwater oceans, we asked, "How do loons adapt to salt water?" You can imagine how hungry loons may be after a long flight when they first reach the ocean. Suddenly the only things to eat and drink are salty fish and salty water. Their bodies must be able to handle salt right off the bat! Luckily, loons have a built-in adaptation: salt glands in their skull between their eyes. Dr. Judith McIntyre, an authority on the Common Loon, found that "even young chicks, no more than two weeks old, are competent to remove salt if they are fed saline (salty) solutions." (In the photo, the skull on the left shows the depression where the salt glands were removed.) Photo Quiz: Response to Challenge Question #2 Photo: Woody Hagge "At what time of year was this picture taken, and how do you know?" This picture shows a loon in summer or fall. The two clues are the loon's black-and-white breeding plumage--and its red eyes! "Loons only have red eyes during the summer," says biologist Dave Evers. In winter, while they are in their grayish plumage, their eyes are not red but gray. Sometimes an answer leads to another question! Dave Evers continues, "Maybe their red eyes are part of attracting mates. Or, perhaps loons have red eyes because any other color would be a disadvantage in deep water. You see, visible light really has many colors (like a rainbow) and red is one of the first colors of the rainbow to be filtered out by water. In other words, beyond a certain depth (like 15 feet) the red part of the light is no longer there. (Blue and indigo colored light travels deepest and that's why you see blue water reflected back to your eyes.) This suggests red eyes might help loons see under water, but then why don't the loons retain their red eyes in the winter when they need to dive in deep ocean water? Also, why don't other diving water birds have red eyes? (Exceptions are birds called grebes.)" What do YOU think? It's Time to Watch for Loons! Report your First Loon to Journey North Do you live where loons nest? In many places, this is a good time to start watching for loons. Go out to large, open lakes to look and listen. Please remember to report any loon sightings to Journey North! 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-loon@learner.org 2. In the Subject Line of your message write: Challenge Question #3 (OR #4 OR #5) 3. In the body of your message, give your answer to ONE question. The Next Loon Migration Update Will be Posted on March 23, 2000 Copyright 2000 Journey North. All Rights Reserved. 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