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Robin Migration Update: March 6, 2001
Today's Report Includes:
- This Week's Migration Maps and Data
- More Robins Heard Singing First Songs (and That's Not All!):CQ #7
- Still feels like Winter: Challenge Questions #8 and #9
- Northern Observations Posts: Looking and Listening for Robins Changing
- Changing Seasons, Changing Behaviors: Challenge Question #10
- Geography, Tulips, Robins: Discussion of Challenge Question #3:
- Temperature and Migration: Challenge Question #11
- Teacher Tip
- Discussion of Challenge Questions #4, #5, #6
This Week's Migration Maps and Data
The weather was unseasonably cool last week across the Central USA, where we're still waiting in earnest for the robins to push northward. The biggest storm of the year is now blasting the East Coast, so there won't be any migration there until that storm moves on! Next week is mid-March, so the robins are surely getting restless. We expect to see a big migratory push just as soon as weather permits. Let's see what next week's weather brings.
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More Robins Heard Singing First Songs (and That's Not All!)
Our song map is filling in as the spring air fills with robin songs. How often DO robins sing their song anyway?
Challenge Question #7:
"Counting the first spring song--and all the times your backyard robin sings until the end of the season--how many times do you think your robin will repeat its song? (In your answer, explain how you arrived at your estimate.)"
(To respond to this question, please follow
the instructions below.)
Northern Observation Posts: Looking and Listening for Robins
Once the migration spreads north of the U.S. border, willing volunteers will help us track robins all the way to Alaska. Look for the yellow stars on the map above and you'll see our Northern Observation Posts.
One of them said, "We are more than willing to help, but don't hold your breath. We rarely see them before the beginning of May." We'll be hearing more updates from all our northern observers soon.
Still Feels Like Winter
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Mrs. Kloewer's class in York, Nebraska wrote about several robins they just saw. " We don't know what they're going to eat because the ground is still way too frozen for worms to come up."
In Durham, NC, an observer said, "The weather took a real tumble and we had snow, sleet, freezing rain--and what did I see the most of? Robins!"
From Merrimack, NH, Ms. LaCroix of Mastricola Middle School wrote, "Winter in New Hampshire has been very snowy and cold all winter...not the place for these migrants to return to yet with the ice storm we had last night!"
This makes us wonder how you would answer:
Challenge Question #8:
"Which would be worse for robins in March: a blizzard dumping over a foot of snow, with temperatures dropping below zero, or an ice storm dropping a half-inch of sleet, with temperatures in the upper twenties? Explain your answer."
Challenge Question #9:
"In cold weather, which is more important to a robin: food or shelter?"
(To answer these questions, please follow the
instructions below.)
Changing Seasons, Changing Behaviors
Observers have been reporting robins behaving just as expected during the winter. For example, a Texas observer this week reported "large flocks vacuuming the lawn," while a former resident of Rochester, New York wrote,
"Of course many robins left for the winter, but those that stayed on simply changed their habits. They move deeper into the heavy cover in wooded ravines with small patches of open water and lots of fruit. People weren't seeing them as readily and assumed they were gone."
When breeding season comes, will robin behaviors change? The answer is yes, and the changes are so obvious that
you could identify the season by simply watching behavior. Read the list of reported behaviors below, and tell
us your answer to:
Challenge Question #10:
"Which behaviors listed below would you NOT see during the breeding season? Explain."
(To answer this question, please follow the instructions below.)
- looking for rosehips on rose bushes
- eating dried leftovers from apple and crabapple orchards and grape arbors
- searching for any berries that remain on sumac and mountain ash
- flitting about in holly bushes next to a house
- flocks of robins eating berries off pyracantha or firethorn bushes
- 10 to 20 robins in every tree
- sitting evenly spaced about 3 feet apart
- flying in large flocks overhead
Geography, Tulips, Robins: Discussion of Challenge Question #3
Last week we compared maps and found that robins seem to be singing in the same places where tulips are up. We asked: "What is it about the geography of North America that you think causes this pattern? In your answer, describe where robins are singing and tulips are emerging this week. Why do you think this is so?"
The maps you saw in last week's Update showed robins singing and tulips blooming along the coasts. It will help you to know that the climate of North America illustrates what's called "continental effect" and "maritime effect." Springtime temperatures are warmer along the coasts due to the moderating influence of the ocean. (Since water warms and cools more slowly than air, water has a more constant temperature year-round than land does. This means that land near the ocean has a more constant temperature than land at the same latitudes mid-continent.) Because winter temperatures are not as cold near the ocean, spring events occur earlier in those areas. This means that spring doesn't just move north, but it moves north FIRST along the COASTS. Both tulips and robins respond to those warmer temperatures--first near the coasts, and then inland. If you're curious to learn more, do a Web search using the words "Continental Effect" or "Maritime Effect."
Temperature and Migration: Testing a Theory
As long as temperatures are on your mind, here's another challenge! You can test an age-old theory about robin migration by asking, "Is it true that robins arrive when the isotherm reaches 36 degrees F?" The word "isotherm" means same "temperature." The isotherm is an imaginary line that connects places having the same average temperatures.
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The isotherm moves across the continent as temperatures warm in the springtime. You can test whether robins travel with this imaginary line of same temperatures by following the steps in this lesson:
Then come back and see if you can answer:
Challenge Question #11:
"Why do you think it would make sense for robins to migrate with the 36-degree isotherm?"
(To answer this question, please follow the instructions below.)
Teacher Tip
If your robins are already back, students can still enjoy the challenge of figuring out whether the 36-degree isotherm applied to your area by going back to records of daily high and low temperatures. OR, you may wish to test the isotherm theory to see whether it applies to the appearance of earthworms in your area. You can also choose another location farther north and watch for correlations between the 36-degree isotherm and the arrival of robins in that geographic area.
Low-Flying Flock: Discussion of Challenge Question #4
We asked you to think about this: "What are some reasons why robins might fly at a different altitude than hawks? What are some reasons why nocturnal migrants might fly higher than day migrants?"
Let's hear it for the fourth-graders from Ms. Sheer's class, the Fifth graders from Tom Longboat P.S. in Scarborough, Ontario, and seventh graders from Iselin Middle School in New Jersey. These good thinkers covered lots of reasons! Here's a summary what they came up with, plus a few more ideas from our Robin expert, Laura:
Robins flap constantly while flying, unlike hawks and eagles, which soar and rely on thermal air currents or updrafts to hold them aloft. Thermals can carry hawks and eagles very high in the sky. Since these birds aren't doing as much work as flapping robins, they can more easily handle the thin atmosphere at high altitudes. Nocturnal migrants can't see where they're going, and navigate by the stars. They need to be above low clouds to see the stars, and need to be high enough up that they won't collide with hills, mountains, and other obstructions that robins flying in the daytime can easily see. Day-flapping migrants have no great reason to be up high, and just in case a Sharp-shinned Hawk or other predator suddenly drops in, they probably feel safer when not too far above a sheltering tree.
Feeding and Foraging: Discussion of Challenge Question #5
"Why might worms be available earlier in a bare cornfield than on a lawn?"
"Robins can easily spot worms in a bare area rather than in a lawn filled with grass," said Mahak, Melissa, Louis, and Joe from Grade 7 at Iselin Middle School. The worms very likely rise to the top quicker on fields than they do on lawns because the bare soil is darker than grass, collects more sunlight, and therefore warms up faster.
Seeing Isn't Always Believing: Discussion of Challenge Question #6
Last time we wondered: "Why would robins be drawn to feeders with birdseed even though they don't eat birdseed?"
Hooray for Iselin Middle School seventh graders (Giana, Danielle, Robert, and Anthony) who thought insects were the answer! Yes, the robins are probably eating worms or insects in the seeds. Snow on frozen ground might be all the more reason birds would look in the birdseed for insects.
If you want to feed robins during cold or stormy weather, better offerings are frozen cherries, blueberries, or strawberries, or live mealworms. (But because most robins never eat at birdfeeders and don't expect handouts, some never do figure out how to take food from people.) See more about this in last fall's Journey South Report:
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 #7 (or #8,#9, #10 or #11).
3. In the body of each message, answer ONE of the questions above.
Please Report the First Robin you SEE, the first robin you HEAR singing, and other interesting robin observations.
Your reports will be incorporated into these Robin Migration Updates.
The Next Robin Migration Update Will be Posted on March 13, 2001
Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form
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