Common Loon Common Loon
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Loon Migration Update: February 22, 2001

Today's Report Includes:

Welcome to the Journey North Spring Loon Migration Season!
Commom Loon Range Map
Map courtesy of MacalesterCollege

We begin our season each year while the loons are on their wintering grounds. When their migration begins in March, we hope you'll help us track their journey north.

Where Are Loons Right Now?
If you live inland where snow covers the ground and ice covers the lakes, you might be tempted to head for Florida. That's what many of our northern Common Loons do! Loons are aquatic birds, migrants that divide their time between oceans, where they usually have been considered coastal birds, and freshwater lakes. Right now, they're wintering in the ocean where they stay for several months each year. That's what we know for sure, but there's a lot more that we DON'T know! Do individual loons prefer certain wintering sites? How does weather influence the location of loons in winter? Do loons move up and down the coast as weather and food supply permit? Can they fly the whole time they are on the wintering grounds, or does molting keep them grounded?

These questions have long made scientists curious, but answers are slow in coming. That's because loons are so difficult to band; these fast fliers and deep divers are hard to catch! Now there's a new and better way to follow the movements of loons: using satellite transmitters. This is such a new and unique method that only a few loons have ever been studied. Journey North is indebted to loon biologist Kevin Kenow for sharing his data with us!

Meet Loon Biologist Kevin Kenow

Kevin Kenow

We're proud to introduce Kevin Kenow of the U.S. Geological Survey in LaCrosse, Wisconsin. In the fall of 1998, Kevin and co-investigators Michael Meyer, Peter Reaman, David Evers, David Douglas, and Jeff Hines accomplished a historic first. Taking advantage of recent technology whereby loons fitted with radio transmitters could be tracked by satellite, they used radio telemetry to track Common Loons during fall migration. Once tagged with a PTT (platform transmitter terminal), a loon can be tracked from a computer using orbiting satellites. They wondered how far a loon flies in a day, how many times it stops, or what route it travels. Last year, Kevin's team shared the data from Loon #2539 with Journey North. (Kevin told Journey North that he has had no contact with that loon since February, 1999.)

In late July 2000, Kevin placed PTTs on two adult loons, but the batteries expired before migration began. His co-investigators this time were Walter Piper of Chapman University in Orange, CA and Michael Meyer of Wisconsin DNR. One more loon was radiomarked in September 2000, and you'll meet that loon today. These scientists have generously chosen to share data from this single loon with Journey North so YOU can join in this groundbreaking research. It's almost as good as flying with a loon!

What are Kevin's goals for the study? "The objective in marking this bird was to assess the feasibility of capturing and radiomarking a juvenile common loon with the intent of conducting a large scale study of movements and survival of juvenile loons."

One Loon On-Line: #15746

Radiomarked Juvenile Common Loon
Photo Courtesy K.P. Kenow, USGS

Kevin and his co-investigators developed the techniques to radiomark a juvenile loon. This photo shows a juvenile loon with a PTT. You can see the aerial for the transmitter, but take a closer look at the loon's bill. Kevin says, "Please excuse the blue fingernail polish." Why do you suppose you see fingernail polish on the bill?

The loon in the current study was captured on Lost Lake, Vilas County, WI on September 26, 2000. Kevin and his co-investigators fitted the bird with a PTT--and it became Loon #15746. (No photo of Loon #15746 available.) Then the scientists released it and watched their computers to see what happened. While Kevin had hoped track the bird through spring, the battery signals grew very weak. At this writing, Kevin is still receiving data from #15746, but says, "Some of the sensor data is non-sensical and indicates to me that the battey voltage may be critically low."

But here's ONE thing Kevin discovered with the help of Loon #15746: "After reviewing the bathymetry data it appears that this bird has been in water depths of 20 feet to 120 feet." Read on to see how you can use the migration data in today's report to make some other discoveries for yourselves!

You're the Scientist: Challenge Question #1
Map for Loon #15746
click on the image to enlarge

Where is Loon #15746? How far and how often did this loon move? You're the scientist, and your job is to make a "winter home range map" for Loon #15746 using the data provided. Or, simply print and analyze our map, which appears to the right.

Then take a good look at the map. Look at the data for dates and distances traveled when this loon moved. Think about facts shared by Kevin above, and research what food this loon might be eating on her wintering grounds. Your challenge is to measure Loon #15746's "winter home range," and to analyze her movements. (See Teacher Tip below.) Remember to create a clear topic sentence for your paragraph and try to write the best verbal description you can.

Challenge Question #1:
"Based on the data and map, how would you describe the winter home range of Loon #15746?"

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

Range and Territory: Some Definitions
When a bird species is migratory, its range is customarily divided into breeding range, where the species nests, and winter range, where the species resides between fall and spring migrations. Here are some definitions that should help with your work today:

Home Range: The area a species occupies in the course of its normal daily activities.

Territory: The portion of the home range that an animal defends against intruders. (The intruders may be of the same or of a different species.)

For this report, we are calling the locations occupied by Loon #15746 a "winter home range" on the individual level.

Teacher Tips: Using Satellite Data
Depending on the age of your students, the skills you want to teach (and your own comfort level with satellite data!), you may want use the migration data in different ways. Here are some tips and background lessons to help you get ready:

Make Your Own Migration Map, Or Print and Analyze Ours
The satellite data provides an excellent exercise in use of latitude and longitude, and plotting the data develops students' mapping skills. We provide the same data points that Kevin Kenow receives from the satellite. However, if mapping is too difficult or laborious (or if it simply doesn't meet the skills your students are learning), you can skip the mapping step completely and simply print out our maps for analysis. Our Challenge Questions usually refer to the interpretation and analysis of data, so even if students do not make their own maps, they won't miss this important component.
  • How to Map Satellite Telemetry Data
    This lesson includes charts with step-by-step instructions for pinpointing an eagle's latitude and longitude on a map, but you can use the same procedures for the loon data. By putting a transparency on top of their map, students can draw on it to find the exact location more easily.

Calculating the Wintering Range
The lesson below will help you get comfortable with satellite data, so you'll have a feeling for the distances involved when a bird's latitude and longitude readings change. This lesson will help students determine the wintering range of Loon #15746 to answer this week's Challenge Question #1.

Try This!
The map in this report makes it clear that loons migrate between freshwater lakes and saltwater oceans. Ocean life is very different from the freshwater lakes where a loon hatches and begins life. Suddenly, loons are drinking saltwater and eating saltwater fish. When it rains, a loon can drink fresh rainwater dribbling along its beak. While it's raining, it may also drink from the water's surface before the lighter fresh water gets mixed in with salty ocean water. But if days pass without rain, the loon has no choice but to drink saltwater. If you drank just half a glass of saltwater, you'd very likely vomit--a good thing because it would protect your body tissues from the life-threatening dangers of too much salt. Why is salty water so dangerous to living things that aren't adapted for it? Try this demonstration for some ideas:

Freshwater to Saltwater: Challenge Question #2
You can imagine how hungry loons may be after a long flight when they first reach the ocean. A loon's body needs to be able to handle salt immediately! How? That's the question!

Challenge Question #2:
"How do loons adapt to salt water?"

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

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-loon@learner.org
2. In the Subject Line of your message write: Challenge Question #1 (or #2).
3. In the body of your message, give your answer to ONE question.

The Next Loon Migration Update Will be Posted on March 8, 2001

Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form

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