American Robin Migration Update: March 4, 2003
Today's Report Includes:
- This Week's American Robin Migration Maps and Data
- Diet of Worms? Challenge Question #3
- Do Robins Really Follow the 37-Degree Isotherm?
- Announcing Journey North's 2003 Early Bird Contest! Challenge Question #4
- News from the Northern Observation Posts
- Tracking Individuals: Discussion of Challenge Question #1
- Winter Robin Variables: Discussion of Challenge Question #2
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Why does this robin look bigger and fluffier than summer robins? Is it a male or a female? Or is it possible to tell? Notice how tiny the pupil of its eye is. What color is the iris? Copyright by Ann Cook |
Lots of people have been noticing robins! Robins have been seen in the Winnipeg, Manitoba, area all winter and at the University of Guelph in Ontario during a snowstorm. But they've also been found in big numbers in Florida and Texas. Children at the Poquoson Elementary School in Poquoson, Virginia, wrote on February 12 that "Last week we noticed individual robins singing and eating earthworms. It has been very cold and it snowed this weekend. I have seen one or two robins at one time at the birdfeeder. They have been trying to get worms from the ground which is saturated with rain and cold. We are wondering if the cold snap will harm the robins?" Fortunately, robins do just fine in cold weather as long as they have fruit, and when they eat up all the berries or crabapples in one spot they just move on.
On February 27, Ruth wrote from Hoagland, Indiana about seeing a robin: "She was sitting in the Sunset Maple just looking at all the snow...four foot drifts...and thinking she made the wrong turn!!" Sometimes robins do look a bit befuddled when the snow comes down. Maybe they feel the same way we do when we're yearning for spring. But they're not saying, so how could we ever know?
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We've also been getting our first questions from people who have problems with robins bonking into their windows and patio doors. What causes robins to do this? What can we do to stop it? Learn all about it here:
Diet of Worms?
Do you have any favorite foods that you can get only in summer? Are there other foods that appear on your plate mainly in winter? As seasons change, diets may also change--not only for people but also for robins and other animals.
Robins eat animals 42 percent of the time and plants 58 percent of the time, say researchers Martin, Zim, and Nelson in their book American Wildlife and Plants; A Guide to Wildlife Food Habits. So, what's on the menu for American Robins? Find out here:
Think about what clues robins might pay attention to that make them switch their diet, and then answer
Challenge Question #3:
"List at least three different environmental clues that might tell robins it's time to switch from eating fruit to worms."
(To respond to this question please follow the instructions below.)
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Right now worms aren't available except where the soil is unfrozen. Northern robins may wander from one feeding area to another during winter, but they aren't set on their spring migratory course until they can eat worms. Take a look at the map to see where people are reporting worms now, and if you want to dig deeper into worms, take a peek at our worm resource page.
TEACHER TIP: Before reading "A Robin's Menu Through the Seasons," create a concept map to organize facts about a robin's eating habits. Write the topic question on chart paper: What's on the Menu for Robins? List two categories below the topic: Animal Foods and Plant Foods. Use the chart prior to reading the selection to record students' predictions and questions. (This is just one idea from a menu of options in our new Reading and Writing Connections for this nonfiction selection. Check it out! You'll find the lesson link right on the page: A Robin's Menu Through the Seasons.
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Average
Temperaure Week of February 23-March 1, 2003. Which color shows the 30-40 degree isotherm? Photo Courtesy of NOAA Climate Prediction Center. |
Many ornithologists, and Journey North's science writer Laura Erickson, say that robins follow the 36- or 37-degree isotherm during migration. But how can that be possible? Right now many robins are in the north where the average temperature is still much colder than 36 degrees. Try a hands-on experiment to see if robins really do follow the 37-degree isotherm with this lesson:
Announcing Journey North's 2003 Early Bird Contest!
How long will it take robins to reach the end of the road? Once again this spring, students at Sand Lake School in Anchorage, Alaska will officiate our annual Early Bird Contest. In this contest, we challenge you to predict when the first robins will be seen in Anchorage. To enter the contest, simply answer this question:
Challenge Question #4:
"When do you think the first robin will be spotted in Anchorage, Alaska (61.22 N, 149.90 W)? Do you think it will arrive with the 36-degree isotherm?"
(To respond to this question please follow the instructions below.)
In the meantime, here are a few clues about signs of spring in Anchorage from teacher Mike Sterling: "We're seeing lots of mosquitoes and moths and other creepy-crawlies this winter, because this is the winter that never came! We had green grass in December. The little snow that fell in December is long gone, and now The Iditarod, the Iron Dog, and the Fur Rendezvous (all winter-related races or festivals) had to be moved or canceled due to lack of snow."
More clues! Dates of "first American robin arrivals" in Anchorage for the past six years are:
Year |
Robin Arrival in Anchorage |
| 1997 | Week of April 5 |
| 1998 | April 6 |
| 1999 | April 26 |
| 2000 | April 17 |
| 2001 | March 29 |
| 2002 | April 11 |
| 2003 | What's your prediction? |
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Northern Observation
Posts 2003 |
Anchorage is not the only place in the far north where people are waiting eagerly for robins. We have 18 Northern Observation Posts (NOPs) where people are watching and listening for their first robin.
As you read above, it's been a warm winter in parts of Alaska. Make your predictions of when people at the 18 NOPs will see and hear their first robin and record them on the worksheets below. Before you peek, can you guess which NOP observer already has heard a robin? This year for the first time one of our NOPs is above the Arctic Circle. Can you guess which one? You'll seem them all listed, and can compare your predictions to the actual reports, on these worksheets:
Tracking Individuals: Discussion of Challenge Question #1
Last time we asked, "Name at least one way that ornithologists could find out if the robins wintering in Towson, Maryland, are the same individuals that spent the summer there." And Journey North readers put on their thinking caps and came up with some excellent ideas. Iselin Middle School 7th graders Vandan, Laura, Patrick, and Jennifer suggested:
- Record their true song, which is their first song. Then, identify that song when the bird sings it again.
They and their classmates, Sampy, Arslan, Ashley, Adrian, Paul, Dominic, Caitlin, and Hannah, along with Georgie, also suggested:
- Ornithologists can lure robins into a big net and then band one of their legs to identify each individual by their numbers both in summer and winter.
We don't know if researchers have developed a technique for identifying individual robins by their "voiceprint," as they have for Whooping Cranes, loons and some other species, but it's sure an intriguing possibility!. Banding with a numbered band works great for recapturing birds. To be able to recognize individuals from a greater distance, researchers also put on one or two colored leg bands. Using different colors and placing bands on left or right leg, they can identify individual birds from a distance as long as the legs are in view.
Winter Robin Variables: Discussion of Challenge Question #2
Last time we asked, "How many variables can you name that affect where, when and how many robins you might see in the winter time?"
Second grader Dan suggested several:
- Whether and what kinds of fruits and berries there are. (This one is most important of all!)
- Whether and how much clean water there is. (Drinking water is essential for robins, so they are usually found where at least a trickle of open water is available.)
- What the temperature is (37 degree isotherm). (This is most important for flocks of robins during migration. During winter they often are far north of where the temperature is in the 30s.)
- Whether the ground is moist and soft for earthworms. (This is most important during migration, when robins switch their favorite food item from berries to worms. During winter many robins eat no worms at all.)
- How many trees there are for nesting. (Robins don't nest in winter, but this is a very important issue in spring!)
- How many cats there are . (If robins don't notice a cat, they might be there for a while, but that might be too long! To understand why see:
- How many other robins there are. (Often in winter when they associate with other robins in flocks, robins are attracted by other robins.)
Paul, Dominic, Caitlin, and Hannah pointed out that changes in climate or weather, habitat destruction, and food supply in their enviornment may affect where, when, and how many robins might be seen in the winter time.
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 #3 OR #4.
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 March
11, 2003 (data only).
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