American
Robin Migration Update: April
27, 2004
Today's Report Includes:
- Latest Migration News: Robins in the Home Stretch
- Eggstra, Eggstra! Link to Lesson
- Egg-to-Fledging Robin Cam and Journaling Questions
- The Scoop on Poop: Link to Lesson
- Counting Survivors: Challenge Question #9
- Robins in Anchorage: Early Bird Contest Results
- News From the Northern Observation Posts: Only a Few Still Waiting!
- Tracking Temps and Robins: Compare This Week’s Isotherm Map
- Weighty Stuff: Discussion of Challenge Question #8
- Year-end Evaluation: Please Share Your Thoughts!
Latest
Migration News: Robins in the Home Stretch
Things are slowing down! This week’s maps are dramatic signs that
the robins are mostly home and busy establishing territories.
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In many place, Robins have begun nesting:
- “In the past couple of days, American Robins have been observed by our naturalists here at the outdoor school with nesting materials in their bills.” (April 13, Sonora, CA)
- “Found a robin sitting on a nest with 2 eggs. There are many other signs of nestbuilding all through the yard.” (April 22, Clarksburg, PA)
- “A robin has built a nest in the wreath on our front door and as of tonight has laid two eggs. We really want her to be able to hatch the eggs and for the birds to be okay. We hope the opening and closing of our door now and then will not disturb them too much…” (April 16, Highlands Ranch, CO)
What's going on in those nests? You'll find out in this week's report!
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Eggstra,
Eggstra! The Story of Robin Eggs
The main purpose of a robin's life is to make more robins. Migration,
territory, courtship, nest building, egg laying, incubation, and care
of the young--all are parts of the breeding cycle. These activities happen
so robins can pass their genes on to new generations. Robins instinctively
know the best ways to accomplish that. YOU may not know the answers to
all these questions, but robins do:
- Why is it important for mother robin to keep her brood patch hidden when she's not sitting on eggs?
- Why do you think most birds lay their eggs in the morning rather than in the afternoon or evening?
- Why do you think four is the best size for robin clutches?
- Can you think of a reason why robins' eggs might be blue?
- What reasons can you can think of to explain why robins time egg incubation different from hawks and owls?
Curious? Find the answers here as you read the story behind those little
blue eggs:
Egg-to-Fledging
Robin Cam and Journaling Questions
At Upland Hills School in Oxford, Michigan, a pair of robins nested on
a ladder in a geodesic dome greenhouse being constructed by students.
The students at the school made a wonderful compromise so they could continue
to build the dome without disturbing the robins. Meanwhile, one student
studying the babies produced a video showing the baby robins at every
stage from egg to fledging. Upland
Hills School Nest Cam video clips bring the nesting process to life!
Watch video footage of the mother robin incubating her eggs:
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Then see the video clips of (a) the first baby to hatch; (b) one of its first meals, and (c) how many brothers and sisters hatch out.
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After viewing the videos, how will you answer these questions in your science journal?
- What do you think made the mother robin choose this nesting spot, on a ladder inside a partly-finished geodesic dome, for her nest site?
- Why does the mother wiggle back and forth as she starts incubating? Why don't the eggs break under her?
- What is the mother feeding these tiny nestlings?
- Why does the female open her beak when the male flies in?
- Why doesn't the male feed the babies?
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Empty
and Clean! Photo Julie Brophy |
The
Scoop on Poop: Link to Lesson
Take a close look at this robin's nest after the babies have fledged.
Would you expect it to be this clean? Baby robins remain in their nest
for about 13 days. Just about every time the nestlings gulp down some
food, they poop. Let's see--that's 13 days x 4 babies x 356 insects and
worms on average each day--that's a LOT of poop! How on earth do robins
keep their nest clean? Find out here:
Counting Survivors: Challenge Question #9
Whew! Now you know that building nests, incubating eggs and feeding babies is a lot of work. Last time you read Be Mine! Robins and Their Mates. We said that one scientific study showed that about 75% of all fledgling robins die before November their first year. Of those that survive that long, about half die before the next November. About half of all 2-year-old robins die each year, and about half of all robins of every other age die each year, too. If this is true, what’s the answer to...
Challenge Question #9:
"If 200 robins were fledged in a town one year, how many of the fledglings would be alive in November? How many would be alive the following November? How many would be alive the November after that? How many years would it be before all these fledglings had probably died?"
(To respond to this question, please follow the instructions
below.)
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Photo
Anne Cook
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Robins
in Anchorage: Early Bird Contest Results
Back in our March 2 report, we asked Challenge Question #4 to launch our
Early Bird Contest: “When do you think the first robin will be spotted
in Anchorage, Alaska (61.22 N, 149.90 W)?”
The long-awaited official word came on April 22 with this news from Sand
Lake Elementary teacher teacher Mike Sterling: “Robins
were seen in Anchorage on April 12. The first was pretty isolated, though
now the tops of every big spruce around have territorial males proclaiming
their sovereignty over all they see. The geese and ducks are here, too.
We even saw a flock of snow geese in the schoolyard last week. Woo! Lots
of snow still on the ground, though low temperatures are not dropping
much below freezing.
“The first song I heard was on April 12 as I rode my bicycle in
to school. The kids in class have noticed robins in their yards every
day since them. Now there are robins all over the place.”
Hooray! No one had a bulls-eye on the date, but Iselin (NJ) Middle School
7th graders Najea, Brett, Melissa F, and Richard were
the closest to winning the contest with their April 7 prediction. Congratulations!
Thanks to Javed, Gabriel, Justin M, Shivam, Eliott, Om, Mark,
Rima, Sinnamon, Jennifer, Mihir, Josh, Nick S, John and Lukasz for
entering the contest with their predictions too!
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Photo
Marc Landry |
News
From the Northern Observation Posts: Only a Few Still
Waiting!
At Sterling, AK, Elementary School, Sara Heppner said,
“This morning (April 21) a robin greeted me from the top of a tree
in my yard. He was singing loudly and happily, maybe because for once
it wasn't snowing or raining on him!”
How many NOPs have yet to see their first robin? Who is still waiting
to hear the first song? What’s the weather like? View the latest
comments of our NOPs and the charts that show when NOP robins first appeared
and when they first sang:
If you’re curious about wintry weather in parts of Alaska and Canada, take a look at this fascinating Web site:
Tracking
Temps and Robins: Compare This Week’s Isotherm
Map
Were YOUR robins home with the 37-degree isotherm? Maybe you are still
keeping track of the isotherms in your area. Compare the latest map with
the one from last time:
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| April 10 Map | April 24 Map |
- Have robin movements shown a pattern similar to the change in the 37-degree isotherm? (Compare with the migration maps at the top of the Web report.)
- Do the
changes in where the 37-degree isotherm is correspond to where robins
have been singing?
For instructions to calculate the isotherm in YOUR region, see:
Weighty Stuff: Discussion of Challenge Question #8
Last time you learned about robin nesting behavior and we gave you some robin weights. We asked: “Which are heavier: winter robins or breeding robins? Which loses more weight in spring: male or female robins? Why do you think this is?”
A look at the figures showed you that winter robins were heavier than breeding robins, and females lose more weight in spring than males do. This is all because robins are large enough that the eggs are a fairly small percentage of a female’s weight. Females wait to head north, so they don’t need as much body fat as males do. Males migrate early, when weather is colder; when they arrive, their larger size is helpful for them in claiming and defending a territory. Thus, males have an advantage if they don’t lose as much body weight. (Isn't Mother Nature wise?)
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.
In the coming year, Journey North will be fundraising to secure increased support from foundations, corporations and individuals. Your supportive comments will be a tremendous help. Thank you!
Journey North
Year End Evaluation
Please share your thoughts
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 #9.
3. In the body of EACH message, give your answer to ONE of the questions
above.
The FINAL Robin Migration Update Will Be Posted on May 11, 2004.
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North. All Rights Reserved.
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