American Robin Migration Update: April 29, 2003
Today's Report Includes:
- American Robins Still Migrating! This Week's Maps and Data, Challenge Question #12
- Northern Observation Posts:16 Down, 4 to Go!
- Do Robins Really Follow the 37-Degree Isotherm?
- Quick as a Wink: Robins Nesting Already
- Food for Thought: Discussion of Challenge Question #10
- Fright Distance: Discussion of Challenge Question #11
- Year-end Evaluation: Please Share Your Thoughts!
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Photo by Gordon Kratzat
for The Wisconsin Society
for Ornithology |
Although American Robins are already starting to nest in many places, some of them are still on the go! William Bernard from Northfield, Vermont, took his ornithology class on a field trip in the Dog River valley of Central Vermont on April 21. He writes, "For at least an hour there was a steady stream of robins moving to the NNE. I did a few minute-counts and had numbers like 45, 62, and 70/minute flying overhead."
William did the calculations, and now it's your turn! Try your hand at this:
Challenge Question #12:
"Use Williams numbers to make these three calculations:
- What was the average number of robins flying overhead per minute?
- Based on that answer, how many robins were flying overhead per hour?
- If William Bernard was counting them in an area of the sky 200 yards across, and the actual robin front was a mile wide, how many robins were flying by per hour?"
(To respond to this question please follow the instructions below.)
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Northern Observation Posts: 16 Down, 4 to Go!
Bruce Bennett reports, "Well it wasn't a wave, but a trickle of American Robins have reached Whitehorse, YT, on April 20, 2003. The first Prairie Crocus was reported on April 21, right on schedule."
Stan White found more of a flood of them in Homer, Alaska: "Great excitement! We heard our first robin singing on the evening of the 25th (Friday), and by today (the 27th) it seems they have moved into every available place where they can claim a territory. We'll now be looking forward to our other migrants, especially the swallows, but the robins have brought us the message we've been waiting to hear: Spring has arrived!"
When will the last four 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 April 6 - 12, 2003, compared
with Week of April 20 - 26. (No map available of entire continent.) 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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To see baby robins grow
from egg to fledgling, see our Robin
Nest Photo Study! |
As soon as male robins return, they establish their territory. When the females return, they start gathering nesting materials (with the help of their mate) and building a nest (on their own). On April 20, Don Davis reported seeing one robin with nesting materials in Algonquin Park, Ontario. He notes that this is "just one day later than the earliest nest-building ever recorded in Algonquin. Algonquin is a huge provincial park 3 hours north of Toronto. A land of rocky outcroppings, dense forests, bear, moose, etc."
Not many people have the opportunity to see robins and moose in the same area, but most of us do live where we can see robins carrying nesting material. Sometimes they fly right past us and are easy to notice. But usually in order to see robins carrying building materials or actually constructing the nest, we have to pay attention. Do you have robins in your backyard? Watch them, and pay attention to their movements.
What's it like to be a robin building a nest? Try it and see!
To watch a robin's nest from day to day as they babies hatch and grow, or to see videos of a robin incubating and then see her nestlings grow to fledge, see these special lessons:
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Robin Hood at Julie Brophy's
special feeder. What's he eating? |
Last time we told you about Julie's special friend, "Robin Hood," who comes to Julie for mealworms. We asked you to "Name three ways that Julie's supply of food helps improve Robin Hood's chances of successfully raising his own babies."
Iselin Middle School seventh graders Susan, Amtul, Vandan, Patrick, Laura, Sampada, Ashley, Arslan, and Adrian discussed how important it is to allow Robin Hood time near the nest when he doesn't have to spend time searching for food. This allows him to focus on spending time with his young and watching for predators. They also pointed out that Robin Hood's babies will be able to take advantage of the food supply when they fledge.
Also, even if Robin Hood's mate never learns how to eat mealworms, there will be more food available for her because Robin Hood isn't taking any of the easy-to-catch earthworms while he's munching on mealworms. Mealworms are a unique "feeder food," because they're as nutritious as any natural food robins could find, so his body will be maintained in good order, making him strong and healthy and in good shape for raising babies.
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How close can you get
to a robin before it flies away? |
Last time we asked you to go out in pairs and measure robin fright distances. "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?"
We're still waiting to hear from you! Meanwhile, Journey North's Laura Erickson did a quick experiment with her backyard male robin. Every time she saw him feeding in the backyard, the moment she opened the back door he flew away! But when he was singing in her spruce tree, he didn't pay any attention to her as she walked out the door and approached within 6 feet of the bottom of the tree. Let's hear YOUR results!!
Year-end Evaluation: Please Share Your Thoughts
Please take a few minutes to share your suggestions and comments in our Year-End Evaluation Form below. The information you provide at the end of each year is the single most important tool used to guide our planning.
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 #12.
3. In the body of your message, give your answer to ONE of the questions
above.
The Next (and Final) Robin Migration Update Will Be
Posted on May 13, 2003.
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