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American Robin Migration Update: April 6, 1999
Today's Report Includes:
- Robins, Robins, Not Quite Everywhere!
- Some Robin Events to Record
- More Things to Watch For
- Challenge Question # 12
- Things to Listen For
- Challenge Question # 13
- Keep Baby Robins Safe
- Comparing Robin Attitudes at Different Latitudes
- Challenge Question # 14
- Discussion of Challenge Question # 10
- How to Respond to This Week's Challenge Questions
Robins, Robins, Not Quite Everywhere!
Robins are arriving in good numbers in the northern states and
parts of Canada. They've even made it to a couple of our northern Observation Posts! But they're still south of
Sterling, Alaska, where Sara Hepner wrote on April 5, 1999: "No robins yet. In fact, it's snowing hard right
now...a good spring storm. An experienced birder was out over the weekend watching swans and snow geese, however,
so their migration has reached us. We'll keep looking...."And Bill Vedders wrote from Kenai, AK (near Soldatna), "Not yet. We got 4 inches of snow last night. Smart robins if you ask me!"
As we wait for robins to finish their journey north, students in places where they've already arrived can start making observations on backyard robins. Robins are abundant backyard birds, very easy to watch, yet ornithologists have a LOT to learn about them. See how many of these questions you can answer from data you collect about your own robins. You won't be able to get data for all of them unless you have amazingly cooperative robins, so don't worry if you can't figure out some dates. Meanwhile, we'll post an update next week if new northern birds arrive on territory.
Some Robin Events to Record
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date |
event |
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over-wintering robins seen |
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first male robin seen (Make sure to report this to JN!) |
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isotherm when first male robin seen |
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first wave of robins seen (3 or more together in yard) |
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isotherm when first wave of robins seen |
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first earthworm appears (Report this to JN!) |
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first robin heard singing (means your resident robin has arrived and is establishing territory) |
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first female robin seen |
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first males seen in battle |
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nest building begins (If you don't know exactly where a robin nest is located, you can watch for signs of nest building such as the male and female flying with nest materials, or the female with mud on breast. Both sexes gather nest materials, but usually only the female builds. She may begin nest building within a day or two after arriving. The nest usually takes 2-6 days to build.) |
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incubating underway (If you can't actually see the nest with the female sitting in it, you can assume she's incubating when you see her less often-she spends about 50 minutes of every hour warming the eggs.) |
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young hatch (usually about 12-14 days after last egg laid. Watch for adult flying with worm-both parents feed the babies. Broken pieces of blue eggshell on ground may be a sign of eggs hatching OR of a nest predator) |
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first young fledge (about 9-16 days after eggs hatch the young leave the nest, or "fledge." Watch for flightless robins with a spotted breast on the ground or in low branches.) |
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young first take wing ( 2-3 days after fledgling, the young are making their first clumsy flights. How long before they become good fliers?) |
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parents start nesting all over again. (When suddenly only dad is feeding fledglings, it's a safe guess that mom's sitting on eggs again. Sometimes she uses the old nest, and sometimes she builds a brand new one.) |
Robins migrate in groups, feeding together.
Individual males separate from the flock as they each find a suitable territory--this is sometimes when they begin
singing. Sometimes they don't sing until the females arrive. When you hear your first robin sing, search the neighborhood
for females. Can you find any females? In some places you can see flocks of migrating robins feeding together and
hear local territorial birds singing at the same time. Can you find both migrating AND territorial birds in your
area?Weather and food availability can influence the number of days between the arrival of the first male arriving and the first female. Sometimes the first females appear with the first big wave of robins. What is the timing between the arrival of the first male, the first wave, and the first female?
Robins usually build their first nest of the season in an evergreen or on a building. The second and third nests are usually in a leafy tree or on a building. Nests are put in places where the babies will be safest.
Challenge Question #12
"Give at least two reasons why a robin's first nest of the season is usually in an evergreen tree while the second and third are more often in a leafy tree."
(To respond to this Challenge Question, see below.)
Things to Listen For
According to Lang Elliott, an authority on bird vocalizations,
- The robin's song is a territorial declaration
- The "peek" and "tut" calls are heard in alarm situations
- The "whinny" is heard in mildly alarming situations
- The high-pitched "Seeeee" call is given in response to the presence of an aerial predator.
- The "Zeeeup" call is a contact note heard mainly during migration
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Listen to the |
Listen to the |
Listen to the |
Listen to the |
Listen to the Robin's "Zeeup!" call |
Challenge Question # 13:
"Which robin vocalizations do you think would be given by both sexes and which by only the males?"
(To respond to this Challenge Question, see below.)
Keep Baby Robins Safe
If you find a robin nest, study it at a distance! Don't make it easy for your neighborhood crows and other predators to discover the nest. And make sure to keep cats indoors during robin nesting season. When the baby birds fledge, they are like little toddlers--clumsy and inexperienced--and spend a lot of time on the ground where cats hunt. Learn more about Cats Indoors.
Comparing Robin Attitudes at Different Latitudes
While you may have already reported your first robin of the season, many other "robin firsts" are now occurring. In the wake of their migration, the following sequence of events is played out along the path:
- Males arrive and set up territories.
- Females follow a week or two later.
- Pair bonds are formed, mating, nest-building, egg-laying and incubation occur.
- The first young of the year hatch.
Depending where you live, robin families in your region are at a particular point in this annual cycle. The
timing of these activities varies with latitude. In fact, as a general rule, it's estimated that the timing varies
by 10-15 days for every 5 degrees north in latitude. (Of course, this rule is intended for comparing points located
at the same longitude. You couldn't use it for example, to compare timing in California and a location on the East
Coast, since the seasons are so different at these places.) Here's a chance for you to use this rule:
Challenge Question # 14
"If we estimate a 2-week delay for every 5 degrees north in latitude, and we assume robins in Jackson, Mississippi,
are now beginning to lay eggs, when would you expect robins in Madison, Wisconsin, to begin laying their eggs?"
(To respond to this Challenge Question, see below.)
Discussion of Challenge Question # 10
We asked, "What climatological condition might be more important than temperature for robins returning to Las Vegas?" Mim Romero, who lives in the desert, sent us this interesting response: "This year has been a very, very dry year. We had no rain this winter, no spring wildflowers. The desert is very dry. Lawns are now beginning to turn green--. I have xeriscaping in my yard, desert landscaping, so when the robins come they eat the pyracantha berries, no earthworms being available. Maybe for breeding purposes they need a different diet."
Robins can live on sugar-rich berries for their day-to-day energy, but growing robin babies need protein. They
get that from insects and, especially, earthworms. So robins don't normally return in full force to the desert
until there is enough moisture for worms.
How to Respond to Today's Challenge Question
Answer only one Challenge Question in each e-mail.
1. Address an e-mail message to: jn-challenge-robin@learner.org
2.In the Subject Line of your message write: Challenge Question #12 OR #13 OR #14.
3. In the body of your message, answer the question.
The next Robin Migration Update will be posted Tuesday, April 20, 1999.
Copyright 1999 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form
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