American Robin Migration Update: April 15, 2003
Today's Report Includes:
- American Robins All Over the Place! This Week's Maps and Data
- More Sightings from Northern Observation Posts
- Do Robins Really Follow the 37-Degree Isotherm?
- Robin Hood Returns: A Joyful Reunion: Challenge Question #10
- Fright Distance: How Close Is Too Close? Challenge Question #11
- Worming Their Way Up the Food Chain: Discussion of Challenge Question #8
- Energy from the Sun: Discussion of Challenge Question #9
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Julie Brophy's "Robin
Hood" is back in Julie's yard! |
Robins seem to be turning up just about everywhere now. In Gowganda, Ontario, this year's first robin turned up on a woodpile on April 10. In Colonsay, Saskatchewan (one of our NOPs), Cathy Weir writes, "After a very nasty snow storm last Thursday and Friday we thought that it would still be awhile until we saw robins. We were wrong though and two of our students saw a robin in their backyards on Sunday, April 6th." On April 10 in Glace Bay, Nova Scotia, Sandra LeBlanc noticed from our maps that neighboring provinces had reported robins, and asked her students if any of them had seen any. Two students said they'd seen them two weeks before (the last week of March). Once robins are back, they quickly start showing territorial and nesting behaviors. So once you've seen your first, keep watching! There's plenty more to observe!
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Jill Rogers took this
photo in mid-March. Some of this snow has melted, but they're still
getting new snow! No wonder she hasn't seen any robins yet. |
Robins have now been reported from half of the Northern Observation Posts. Mike Sterling wrote from Anchorage on April 7, "I was sitting in my chair at school doing a spelling pre-test with one of my classes when I saw a robin flutter from one tree to another. I feel sorry for these earlybirds. They get here WAY before the bugs hatch, and the ground is still frozen solid. I hope they know something we don't."
Of course, if robins have arrived in half the NOPs, they still haven't arrived in the other half. Jill Rogers from Corner Brook,Newfoundland, reported on April 12, "No robins to report yet. Still lots of snow, however, it is melting. They are forecasting 15 cm (snow) and strong winds again tomorrow! We have had snow on the ground since October 26th. We are tired of it and anxious for green grass. I'll let you know when we see the first robin."
When will Jill and the other final NOPs see their first robins? Check your predictions and keep up to date with news from the NOPs here:
Do Robins Really Follow the 37-Degree Isotherm?
Have you been trying to learn whether robins follow the 37-degree isotherm? Here's a new map to check out. Compare the maps below and answer these questions:
- What color is the part of the maps showing the average 37-degree isotherm?
- Has the 37-degree isotherm moved in the past 2 weeks?
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Average
Temperature in United States Week of March 23-March 29, 2003, compared
with Week of . (No map available of entire continent.) Did the isotherm move DOWN this time? What color is the 37-degree isotherm? Have robin movements shown a pattern similar to the change in the 37-degree isotherm? Photo Courtesy of NOAA Climate Prediction Center. |
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Do the changes in where the 37-degree isotherm is correspond to where robins have been singing? Compare these temperature maps to the migration maps above. Do you think the migration is following the isotherm?
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Robin Hood at Julie Brophy's
special feeder. What's he eating? |
For the past several years, Journey North's Julie Brophy has been visited by a special robin that she could recognize individually. Julie lives in Victoria, Minnesota, and keeps a special "feeder" on her deck for her special robins, orioles, and other birds that don't eat many seeds. First it was Buddy, and then it was Robin Hood. And now Robin Hood is back for the third year in a row. How does Julie recognize him? Why does he call when he wants Julie to come out? What does she feed him? Learn all about these things at
Once earthworms are available, robins can get plenty of natural food in Julie's yard. How does her supply of mealworms and fruit improve Robin Hood's chances of successfully raising babies?
Challenge Question #10:
"Name three ways that Julie's supply of food helps improve Robin Hood's chances of successfully raising his own babies."
(To respond to this question please follow the instructions below.)
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How close can you get
to a robin before it flies away? |
Did you ever try to sneak up on a bird or other wild animal? We humans look like big predators, and in fact, some humans hunt some animals. So it makes sense that wild creatures don't let us get too close. Some birds can recognize individual humans and allow some people to come much closer than others. Robin Hood, for example, allows Julie Brophy to come very close, but he's as wary as any other robin about other people. Many people get chickadees or other birds to take food from their hands, but those same chickadees will fly away from other people without ever getting within an arm's reach. And they will even fly away from people the know and trust sometimes, and will not allow themselves to be caught. Journey North's science writer Laura Erickson has visited many hummingbird feeding stations where the hummers would fly in and feed before the feeders were set up, while the feeders were still being carried by people. But those same hummingbirds would never get that close to people in other settings.
So how close IS too close? You tell us! When robins move in to your neck of the woods, get out there and see how close they allow you to approach. You'll need a long tape measure, a study area (a nearby park or school playground where robins spend a lot of time or someone's yard), a pencil with a point or a stick or tent stake, and a field notebook and pen. Students should work in pairs. One person will be the "fright tester," and the other will be the "recorder." The recorder's job is to stay focused on the robin while the other student moves toward the robin. When the robin flies, the recorder goes to the spot where the robin had been, marks the spot with a pencil , stick, or tent stake, and measures to where the other student is standing. Record the distance in the field notebook. Students can take turns doing each job. In pairs, try these experiments:
- Find a robin searching the ground for worms. The fright tester should slowly walk toward the robin, looking straight at the robin. When it flies, recorder measures and writes down the distance. Do this at least 5 times. Calculate the average fright distance for this hunting robin.
- Try this same experiment walking at the same speed, only this time the fright tester should look away from the robin. Do this at least 5 times. Does the fright distance change when the person is looking away?
- Try this same experiment walking faster, and then running. Does the walking or running speed change the fright distance?
- Try these same experiments with a singing robin. How does fright distance
of a singing robin compare with that of a feeding robin?
Challenge Question #11:
"What is the average fright distance your class observes when students slowly approach a hunting/feeding robin? What is the average fright distance your class observes when students slowly approach a singing robin?"
(To respond to this question please follow the instructions below.)
Worming Their Way Up the Food Chain: Discussion of Challenge Question #8
Last time we asked,"If a Peregrine Falcon killed the hawk that the fish ate, why isn't the Peregrine part of the food chain?"
Food chains are simple ways of showing how energy moves from the sun to plants to animals. They are ways of showing how calories go from on trophic level to the next. The Peregrine that killed the hawk didn't take any energy from the hawk, and so we don't count it in the food chain any more than we count a truck in a food chain that is following the transfer of energy from a squashed rabbit to the vulture that eats it.
Energy from the Sun: Discussion of Challenge Question #9
We asked, "How does the energy farmers use for planting and harvesting come from the sun? How does the energy that runs airplanes, trucks, and trains come from the sun?"
The farmers' personal energy comes from their food, made up of plants and animals that were part of food chains beginning with the sun and ending with the farmers. The energy they used in running their tractors and other farm machinery, and the energy that runs planes and trucks, comes from petroleum products, which are called fossil fuels. Fossil fuels are called that because they come from fossilized plants and animals from millions of years ago. These plants and animals were preserved and then compressed in rock over millions of years. Nothing ate them, so the energy in these fossilized plants and animals has been stored. But they, like all plants and animals, were part of a food chain that started with the sun.
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-robin@learner.org
2. In the Subject Line of your message write: Challenge
Question #10 (OR #11).
3. In the body of your message, give your answer to ONE of the questions
above.
The Next Robin Migration Update Will Be Posted on April
29, 2003.
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