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To: Journey North Students
From: Martha Fischer
Bird Education
Cornell Lab of Ornithology
Ithaca, New York
Answers to Journey North questions about the American Robin
From MAINE:
Q. How do they know when to migrate? -Nisse Greenberg
A. Birds know when to migrate by the length of daylight. Through autumn, daylight hours grow shorter. Then, when winter begins, the days begin to get longer. At mid- to late-winter, birds begin to feel restless. They have an internal clock, and they know that soon it is time to start moving north. Their restlessness (ornithologists call this pre-migratory restlessness zugunruhe) becomes irresistable depending on the length of day...but birds won't start to migrate just any ol' time. They wait for the weather and temperature to be right. Robins follow behind the spring thaw, waiting for the average temperature to reach 2=B0C. And they wait for favorable winds. They want a tail wind-for the south wind to come along and help them move north. So, knowing when to migrate involves an internal clock, a feel for temperature, and the right weather patterns that create south winds.
Q. How do they keep their feathers from getting ruffled?- Kate Healy
A. Look at a bird's feather under a microscope. What you see looks very similar to velcro. How does velcro work. How does a bird's feather stay together? Birds take great care of their feathers-they have to, because if they didn't, they would get cold and wet and would not be able to fly. Many birds have an oil gland at the base of the tail. The bird rubs its beak on the gland to get oil on it. Then it rubs the oil off its beak onto its feathers. This is called preening. The oil makes the feathers water-resistant. Birds also straighten their feathers by running each feather through the beak to make the velcro-like structures zip together to keep the feather intact.
Q. When are babies considered mature?- Tristan Birkenmeier
A. Baby robins are considered mature the spring after they hatch. Robins that hatched out last spring (1995) are mature adults this (1996) spring.
Mrs Herseys 4th grade class Bar Harbor ME.
mhg4@emerson.u98.k12.me.us
From MINNESOTA:
Q. We were wondering if the robin returns to the same nesting place year after year like the geese?
A. This question is hard to answer, because robins all look alike. If you saw a robin in your yard today, how do you know it is the same one or a different one from the robin you saw yesterday?!
In order to find the answer to this question, scientists must capture robins with a fine net called a mistnet. They carefully take the bird out of the net and place a silver US Fish and Wildlife band on one leg (this USFWS band has numbers on it that identifies that bird) Then they put a colored band on the other leg. They might even put two colored bands on the leg. When they catch the next robin, they put the silver band on one leg, and different colored bands on the other. When they let the two birds go, the scientists can tell these two individual birds apart.
By banding birds researchers find that robins return to the same nesting place year after year about 50% of
the time. They may try to get back to the same place, but another robin can get their first and claim the territory,
or something can happen to the bird during migration that makes it impossible for it to get back.
Lois Cleland cleland@anoka.k.12.mn.us
From PENNSYLVANIA:
A. We have record of one banded robin that lived for 11 years in the wild. Captive birds can live longer-a couple of robins have been known to live up to 17 years.
Q. Do robins keep the same mate and if so, and it dies do they find another mate?
A Robins may or may not keep the same mate year after year. If, during one breeding season, the male mate dies, the female usually finds another mate. If, however, the female dies, it is very unlikely that another female will take over the nest.
Q. At night we hear the cheer-up, cheerily cheer-up song...do robins sing different songs at different times of day?
A. No.
2nd grade gifted class at Oley Valley Elementary School, Oley PA Lynda Eckert,Computer Lab Instructor, Oley
Valley Elementary School
leckert@fast.net
From NEW YORK:
Q. How far do robins migrate from the NY, Long Island area?
A. In order to know how far a robin migrates from Long Island, a scientist would need to capture and band an individual on Long Island and recapture it on its wintering ground. The likelihood that the bird would be recaptured is very, very slight. Birds on Long Island probably end up wintering in Florida, Georgia, and Alabama; however, they can range over into Louisiana and Texas.
Q. Where do they migrate to?
A. See above.
Q. Why are robins red-breasted?
A. From all the literature I have read, it seems to be a mystery as to what makes the "red" color in robins. Their breasts and bellies are not actually red. If you were to examine one feather from a robin's breast, you would find it a cinnamon-brown color. We do not know how that color is formed.
Q. How long do robins live?
A. See above answer.
Thank you for considering our questions.
Mrs. Drew's fourth graders at the Covert Avenue School, Elmont, NY
K12ELPZR@vaxc.hofstra.edu
From The MARSHALL ISLANDS:
Questions from Hali, Meria, and Travis in Mrs. Doherty's class.
A. The answer to this questions is unknown. Scientists have noticed that birds that nest in cavities and other dark places have eggs that are all white. Birds that lay their eggs in open nests on the ground tend to be camoflaged...they match their background. What caused blue eggs? Good question.
Q. Is there any specific tree they nest in?
A. Nests that are built early in the breeding season tend to be built in coniferous trees. In general, robins build their nests in either coniferous or deciduous trees.
A. A robin was clocked flying at 36 mph.
George Seitz Elementary School popejoy@ALOHA.NET
From NEW YORK:
Mrs. VanDusen's kindergarten class asks:
Q. Why are robin's eggs blue?
A. See above answer
Q. Do they remember their babies after they are grown?
A. There is no evidence that shows that parent robins remember their offspring after they are grown.
regards
Ann VanDusen AVANDUSE@erie.WNYRIC.ORG
From WISCONSIN:
Q. What do the robins eat when there is snow on the ground? They came Sunday and we had snow and no worms.
A. When snow is on the ground, robins resort to eating berries.
Q. What could we put out to feed them?
A. You could put out raisins and dried currents, small bits of dried apple.
From MINNESOTA:
We would like to know the following:
Q. How many feathers does an adult robin have?
A. According to feather counts, they have up to 3,000 feathers.
Q. Do their feathers change color from winter to spring when they're migrating?
A. No. They change feathers (molt) at the end of the summer, but they do not change colors.
Q.. Do they lay eggs more than once a year and if so how many eggs do they lay each time?
A. Robins lay two or three clutches of eggs, most often two clutches. Each clutch contains an average of 4 eggs.
Thanks for answering our questions.
The robin group from room 62
Yolanda,Meta,Adam,Feng,Brian,Sara
(Rita Christenson) rchriste@ties.k12.mn.us
From WISCONSIN:
Q. Why do robins migrate leaving the warm regions to go north?
A. One theory offered by ornithologists is that birds that nest up here in the north are actually tropical birds that move north to take advantage of the long days, abundant insects, and more space (ie they don't have as many other birds to compete with for the insects.)
Still seems like a silly thing to do, to leave Florida when there is still snow in Wisconsin. But think about this: In the winter-time, many birds exist together in the warm parts of the US and Mexico. That means a lot of birds are competing to find enough to eat. Now comes spring and these birds want to raise young, which means they need to feed not just themselves but from 4 to 6 other hungry mouths. To raise youngsters, parent birds must be very efficient-they must be able to find LOTS of high-quality food (lots of protein for the growing chicks) in as LITTLE time as possible. They'll have to hunt longer and harder in the south where more birds are looking for the same thing. When they move north, they have fewer birds to compete for lots of insects over long periods of daylight. This enhances the chance for the survival of the young.
Q. If some robins overwinter in northern lattitudes and stay there year-round is the robin considered a true migratory bird?
A. The word "migration" refers to any regular movement from one place to another. American Robins are migratory in that the species as a whole regularly moves north and south. A few populations or groups may stay year round in one location, but the species as a whole is considered migratory.
From MINNESOTA:
Q. How long do they live?
A. See above.
A. Some robins can fly 200 miles. Their average flight speed is 20-30 mph.
Q. How many days can they travel?
A. Robin migration is slow, and can take many days. Because they move north following the isotherm or spring thaw, movement is sporadic. They might go 200 miles one day, and then rest and feed for the next two days before moving another hundred miles. Their migration can take two, three, even four weeks.
Chris Phetprasith at Lakeview Elementary
kstone@metro2.k12.mn.us
From NEW YORK:
Q. How are robins' mates chosen?
A. Surprisingly, very little is known about American Robin courtship behavior. This is because they have very subtle "displays" and it is difficult to tell whether or not these activities are geared for choosing a mate. Robins do seem more wedded to their territory than to each other, so it might be safe to guess that a female robin chooses a male by choosing his territory first.
Q. Why do robins return to the north when they do, or at all? Isn't in nicer down south?
A. See above question.
Q. How do they track down, or sense, worms? Aaron Card
A. They use their eyes. Have you noticed robins in your school yard hopping from place to place, cocking their head this way and that? Because their eyes are on the side of the head, they must tilt the head to see objects directly in front of them. They do not use their sense of smell-like other birds, robins have a terrible sense of smell. Experiments have ruled out the possibilities that robins feel vibrations that worms make or that robins hear worms moving.
Rosymary Mauer maurerr@sued.syr.edu
From MINNESOTA:
Hi! Here are the questions my science students had about robins:
Q. How well do robins see and hear in comparison to other birds?
A. I did not find information to shed light on a comparison on hearing. However, in the reading I have done about eyesight, robins seem to have average eyesight. All birds have a structure on the retina call the fovea that serves to magnify objects. Because robins feed on worms which move very slightly, the robin needs a slightly larger fovea than say, a goldfinch which eats just seeds.
Q. Is there any advantage to having blue eggs?
A. See answer above.
Q. How many worms does the average robin eat per day?
A. I honestly don't know.
7th Grade Science Students, Fosston High School, Fosston, MN
Margaret Menzies,rjohnso@informns.k12.mn.us
From PENNSYLVANIA:
Our team of fifth graders is responsible for getting the information about Robins to the first graders in our
building. Thanks for helping us with these questions.
Q. Why don't robins eat bird seed?
A Robins do not eat seeds because their digestive system is not designed to work on seeds. Seed eating birds have well developed gizzards where the seed is ground by the muscle and grit in the gizzard. The gizzard is not as well developed in robins.
Q. Why are they called American Robins?
A England has a bird that looks something like the robin. They call it "Robin". When the English came to North America centuries ago, the named the similar bird "Robin" also. These two robins are different species altogether. The scientific name for Europe's Robin is Erithacus rubecula. The American Robin's scientific name is Turdus migratorius. Ornithologists in the U.S. use the the formal name "American Robin" to be clear that they are talking about the Robin of Europe.
Q. What kinds of insects do they eat?
A. American Robins eat caterpillars, ants, termites, cutworms, cicadas, weevils, to name just a few of the insects they eat.
Sharon Chambers schamb+@pitt.edu
From ALASKA:
Q. Would a robin stay for the winter in Alaska? Would it survive?
A. I checked Christmas Bird Count data in Alaska, and found a few records of robins being found around Fairbanks, Anchorage, and Glacier Bay during December. The likelihood of these birds surviving a winter of sub-zero temperatures is very slim. They need to eat to stay warm. The only food they would find is berries. It would be very difficult for them to eat enough during the short day light hours to stay warm through the long nights.
Q. Why would it stay here? What are it's chances of living?
A. See answer above.
Roger Post,Weston Krizan, Jessica Halliwill, Zachery Dunlap, Sand Lake Elm.
Anchorage, AK "W. Mike Sterling" sterling@corcomsv.corcom.com
Martha Fischer
Project PigeonWatch Coordinator
Bird Education
Cornell Lab of Ornithology
Ithaca, NY
**Visit the Cornell Lab of Ornithology Website
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