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Answers From The Robin Expert, Laura Erickson
Special thanks to Laura Erickson for providing her time
and expertise in responding to your questions.
To learn more about Laura, the wonderful books she's written, and a host of other information from her about birds,
go to: "For the Birds"
From: Pennsylvania
Lock Haven Junior High School
nheilman@oak.kcsd.k12.pa.us
Q: I understand that the robin is a member of the thrush family. Why doesn't it resemble a thrush more closely?
A: Robins actually DO look a lot like thrushes--at least when they're babies! They have spotted breasts just like other thrushes. Their beak and body shape are also very thrush like, and their complicated songs have many tone qualities similar to thrushes. They also hop and feed on the ground like their relatives. It's hard to say why they turned out so much more colorful than other thrushes, though the rusty on a hermit thrush's tail isn't much different than the red on a robin's breast.
Q: Why is the robin's egg greenish-blue in color? I would think that it would be safer from predators if it were not such an unusual color.
A: Actually greenish-blue is similar to the color of some leaves, especially of the spruce trees that robins often use for building their first nest of the year. Perhaps the color is used for camouflage.
Q: Can robins anticipate an early autumn and return to their wintering grounds earlier than normal?
A: Robin migration seems to coincide with the time when berries are very abundant, perhaps so that they can feed along the way. They move faster when we get high-pressure systems with cold fronts. The last half of September, 1988, there were a lot of rainy days, which kept robins from flying much. It cleared up on October 1, and that morning I counted 62,707 robins flying along the north shore of Lake Superior. They had all been waiting until conditions were right for moving.
Can they predict the future? I have a very hard time imagining how they could. But no one really knows for absolute certain--except of course for the robins. But they're not talking.
From: Wisconsin
Pidgeon River Elementary
jarnoldi@sheboygan.k12.wi.us
Q: Why do Robins have blue eggs?
A: Just about all thrush eggs are at least partly blue. It's hard to say why. Perhaps the bluish-green in the shade of the nest makes them appear camouflaged in the dappled light of tree branches. Actually greenish-blue is similar to the color of the spruce trees that robins often use for building their first nest of the year. Perhaps the color is used for camouflage.
Q: Why do the male robins always come to Wisconsin first?
Male robins return first because they are the ones in a pair responsible for establishing the territory. When they return, it is still early enough in the season that sometimes it snows and early spring storms are normal. Surviving during this time is tricky, but males can handle the stress. Females can also handle this stress, but then wouldn't necessarily have the energy to produce healthy eggs. So they conserve their energy and strength by delaying migration until the weather is warmer and more predictable.
From: Colorado
South Park Elementary
garyt@csn.net
Q: Why do some robins remain in our area all winter while most robins migrate?
A: In fall robins have two choices--they can stay or leave. If they stay, they have to face the limited food supply and cold weather of winter, and if they leave, they have to go through all the hardships and dangers of migration. But the first robins to return in spring, or the ones already there from the winter, have the first choice of territories, so if they survive, they have an enormous advantage.
Q: How do the ones that stay find enough to eat?
A: Robins that stay in cold areas eat berries and fruits left over from summer and fall. If there are underground springs, sometimes they can even find some worms. There isn't any new food growing in most northern places in winter, so if they start running out of food in one place, they move on further south.
From: Nebraska
Fredstrom Elementary School
monarch@lps.esu18.k12.ne.us
Q: Do the Robins in my yard come back to my yard after they migrate? Mrs. Hedrick's 4th and 5th grade Mrs. Thornton's science class
A: Yes, very often they do, especially if they had good luck in raising babies. Robins memorize all the safe places for building a nest and finding food and shelter on their territory. If they go to a different territory the next year, they have to start all over rather than just dong what worked the year before.
From: Minnesota
museum magnet school
lkindig@mms.stpaul.k12.mn.us
Q:Why are robin's eggs blue?
A: Just about all thrush eggs are at least partly blue. It's hard to say why. Perhaps the bluish- green in the shade of the nest makes them appear camouflaged in the dappled light of tree branches.
Q: Why are they called robins?
A: When the first English-speaking settlers came to America, they were often homesick. There's a little brightly-colored, friendly bird there called a robin-redbreast. It isn't related to our robin, and is more brightly colored than our bird, but because they both have some reddish on the breast, the settlers started calling ours a robin. "Robin" is an affectionate form of the name "Robert," and was just a nickname for their bird at first.
Q: Why do robins have an orange stomach?
A: No one knows why some birds have bright colors or bold patterns, except to make them look more attractive to possible mates and more healthy and fit than other birds. I guess they have reddish undersides for the same reason that some kids have reddish hair. When I find out why that is, it will be a great scientific breakthrough!
From: New Jersey
Iselin Middle School
susamel@juno.com
Q:How do robins find worms underground?
Q:How do they know they are present? Students of Iselin Middle School,Iselin N.J.
David Falzarano, Jenny Wade, Michael DiPrima
A: There are several theories about how robins locate worms, and the truth is probably a combination of them. Some people think robins may be able to feel subtle movements of worms underground through their feet. Some people think they may be hearing them. Others think that they may actually see them through tiny airholes or passage tunnels.
From: Florida
Largo High School
shapiroa@concentric.net
Q: Where do they live?
A: Robins live everywhere in America north to just beyond where trees can grow. They sleep in trees, usually on branches close to the trunk where they are safest from predators spying on them. They spend their days in trees and shrubs and on the ground.
Q: What is the role of the male and female robin?
A: Male and female robins have very similar lives except when nesting. During this time, they share some jobs and assign others to one or the other. The male is responsible for keeping other male robins off the territory, for finding nesting materials for the female, and then for finding food and feeding the babies. The female is responsible for keeping other female robins off the territory, laying and then incubating the eggs, and finding food and feeding the babies.
Q: How much do robins weigh on average?
A: 64.8 - 84.2 grams, which is 2 1/3 to 3 ounces. That means a robin would balance three good-sized birthday cards.
From: Illinois
James Hart Junior High
ghuizinga@kiwi.dep.anl.gov
Q: Why do robins chase each other during mating?
A: Usually any chasing that happens between robins is between two males or two females, since they are highly territorial when nesting. Pairs are very private about actually mating.
Q: When do robins make their nests?
A: Female robins start building very soon after returning in spring, which is usually before the trees leaf out. To protect the nest from rain or even late snow, she usually builds it in a spruce or pine tree, or on a building. After the first batch of babies grows independent, the pair will usually build a second nest, which is more likely to be in a deciduous tree (that is, one with leaves, like a maple or oak), and raise a second brood. In some places, robins will even nest a third time in the season.
From: Texas
Saint Andrew's Catholic School
muffett3@standrewsch.org
Q: How large are their babies when they are born?
A: The babies are very small--remember--they were just inside an egg, in which they were cramped but still fit okay! They grow very quickly, so that they are almost as heavy as their parents in just about two weeks.
Q: How do they protect themselves from predators?
A: Robins have a couple of warning calls that they make when they spot a predator, which helps other robins to notice the danger. If a hawk flies over, robins sometimes freeze in position, and can hold still for a long time if necessary. One summer I spent a lot of time watching a pair of Merlins (bird-hunting falcons) who were nesting in an area adjoining a robin nest territory. Whenever the male robin sang, he sang at half volume, so he sounded very far away when he was right there!
If robins notice a cat or other mammalian predator, they usually just fly away.
If a predator is stalking near their nest, they may squawk and dart near or even at it, trying to drive it away.
Q: How do robins know when to migrate?
A: At the end of summer, there is so much food for birds that robins pig out. Their bodies start getting lots of fat tissue. At this time, the days are also growing shorter. This turns off the hormones that tell them to nest, and turns on hormones that make them grow restless. They seldom migrate on rainy days, and, based on the data I have from watching migration along LakeSuperior, seem to move most noticeably on days with high barometric pressure and northwest winds.
From: Illinois
Mike Alikonis (8th Science Teacher)
westmiddle@stlnet.com
Q: What do Robins drink when the water is frozen.
A: If they get VERY thirsty, they eat snow, but since most of the food they eat in winter is berries and fruits, they usually get enough water in their food that they can go days or even weeks without it.
Q: How can you tell how old a Robin is?
A: If it has spots on its breast, it was hatched that year. If it doesn't, you simply can't tell!
Q: How fast can Robins fly?
A: Robins fly about 20-35 mph.
From: Michigan
webercon@isd.wash.k12.mi.us
Q: According to their migration, do the robins lay their eggs earlier or later in the season?
A: Robins start building their nests as soon as the females arrive on their territories. This means that robins in the south nest earlier than those in the north. Robins will start a second or even a third nest, and sometimes northern migrating robins are starting to appear in an area while the resident robins are still raising their babies.
Q: Does the weather affect how many eggs they lay?
A: A female robin lays 3-6 eggs, but usually 4. The weather doesn't seem to affect this much. But if the weather is good and food is plentiful, the pair will raise these babies quickly and start another brood, and if the weather is REALLY good, they will even nest a third time. So weather affects how many eggs she lays over the summer, but not in a single nesting.
Q: What does affect the number of eggs?
A: If the female's body is in excellent condition, she might lay more than four. If she's been having problems getting enough calcium or other nutrients, she might lay fewer.
Q: Do robins migrate with any other bird species?
A: I have seen flocks of robins migrating in fall with grackles, red-winged blackbirds, blue jays, kingbirds, and warblers. But most of the robin flocks I've watched were of just robins.
Q: Do they share interact in any way with other species?
A: They eat earthworms, insects, centipedes and spiders. They get eaten by some predators, and try to drive away other predators, especially near their nests. They pay attention to the warning calls of many birds, and when a crow or blue jay starts yelling, they investigate and sometimes join a mob of birds trying to chase an owl or other predator away.
Q: We saw two robins chasing each other with their wings flapping in the air. They were on the ground when they were doing this. Do you know what this means?
A: They were probably two males or two females trying to keep each other off their territory.
Laura Erickson
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