Teaching Suggestions
Special thanks to ornithologist Laura Erickson for providing her time and expertise in responding to your questions.
Laura Erickson's for the Birds
Q: We have an all white robin in our neighborhood. Its offspring have been returning for the last couple of years. All have white splashes like a pinto horse. How common is this?
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Partial
Albinism Courtesy of R. F. Brown |
A: It's not at all common. Although robins are more likely than most species to have albinism and partial albinism, individual robins with white feathers are more conspicuous and easier for predators to target. Also, feathers without pigments aren't quite as sturdy as those with pigments, but are molted no more frequently than normal feathers. True albinos and partial albinos that don't have normal pigments in their eyes have no protection from ultraviolet light, so they are more likely to become blind. All these factors give robins with white feathers a shorter life expectancy than normally-colored feathers. Apparently the all-white robin in your neighborhood has figured out strategies to elude predators and survive despite these other difficulties. I rather doubt that it is a true albino, because blindness so often afflicts wild albinos—with no access to sunglasses— though even that is possible.
Is your robin a male or female? If you see it building a nest, it's probably a female. If it's actually sitting on the nest, it is definitely a female. Female birds are often earth tones to give them better camouflage when on the nest. Because of that camouflage coloring, I would think it would be easier for a normal-colored female to incubate. The interesting question is how robins choose mates, because they don't seem to shun potential mates that have white feathers.
Pigment production is regulated by our genes, so lack of pigment is a genetic condition. That means that any babies produced by an all-white bird would carry the gene. We'd love to see photos of these interesting and unusual birds!
From: Ann Arbor, Michigan
Emerson School
Q: How do flocks get started in the first place?
A: When a brood of baby robins fledge, they are taken care of by both parents for a few days. Then the female gets ready to lay more eggs. When she starts incubating the next clutch of egge, the male continues to take care of the first brood. At nighttime, he leads them to a nice, well-sheltered stand of trees or shrubs to sleep. Other male robins are also leading their babies to this area, which is called a roost. The young birds get used to sleeping in a big group. When the new eggs hatch, the father leaves his older babies to help feed and care for the new nestlings. The older babies are fine on their own, hanging out with other fledglings.
Q: How do mixed flocks get going?
A: If by mixed flocks you mean mockingbirds, waxwings, Pine Grosbeaks, and other fruit-eating birds that join up with robin flocks, they usually get going when the birds are searching for fruit trees. Hearing fruit-eating birds attracts other fruit-eaters, of the same as well as different species, because they all need the same food.
Q: Which groupings would "know" they could blend?
A: Fruit is a kind of food that can spoil or change in flavor over a few days or weeks, and is usually produced in huge quantities more than an individual bird could eat on its own. But depending on the time of year and the place, fruit can be hard to find. That's why birds that depend on fruit have more than one strategy for searching. Fruit trees can be colorful when the fruits ripe. Fruit-eaters are usually attracted to the colors red, yellow, and orange. They also find fruit by using their ears. Fruit doesn't make sounds, so how do they find it? By listening for the sounds of other birds that eat fruit! Those calls draw them in, and since fruit eaters aren't very territorial, they get along quite well.
Robins ARE territorial on their breeding territories, but not at their roosts, nor in feeding trees.
From: Bay Village, Ohio
Q: I live in Bay Village, Ohio about 200 meters from Lake Erie. There are four Washington Hawthorne trees on the tree lawn. Every year around January Robins come and have a feast. Where are they coming from and where do they go? I thought they flew south in the fall. Just a note, this year for the first time they did not arrive until the middle of February. Thank you.
A: You’re close to one of the most important migration routes in the world: the Great Lakes. Birds would be more likely to notice your trees than they would the exact same kinds of trees that are farther from this migration route.
A great many robins don't go very far south in winter, if they can find food. I live in Northern Minnesota, and I often see robins in December and January—always at mountain ash, crabapple, and other fruit trees. Once they clean out the trees up here, they move south. Your robins may have been able to find more food farther north this year, only moseying down to Ohio as they needed more supplies.
From: Oregon, Wisconsin
Q: Hi, Robins are back in Wisconsin. I have never seen a robin eat from a bird feeder before. I thought they mostly ate worms and bugs. Is it common this time of year? March 11, 2006. Judy
A: Sometimes bird seeds get buggy, and if a robin notices a few worms (insect larvae) wiggling in seeds, it will certainly check it out! Also, robins do notice other birds at feeders, and once in a while will investigate to see if there is usable food in the feeder. Robins aren't very good at breaking open or digesting seeds, so it is very unusual for robins to visit a feeder very often unless the feeder has fruit or mealworms. The robins in my yard are used to coming to my feeder for both, so maybe when my robins are passing through Wisconsin, they check out other feeders on the way, just in case!
From: Laval, Quebec, Canada
Q: I'm pretty worried about the avian flu. Here in Canada, the authorities are nervously waiting the arrival of the birds coming from the south. Is there any risk that the Robins or any other of our fine feathered friends are in danger of carrying the dreaded virus and are they in danger of being massively killed by panic-stricken people?
A: It will be extremely unlikely that avian flu will hit songbirds in the US or Canada this year. If you look carefully at where people and wild birds have tested positive, it has always started where poultry is overcrowded and kept in unsanitary conditions. How do wild birds get the virus? When infected chickens poop or are butchered, contaminated feces or washed-away blood and body parts can flow into rivers and streams. This contamination of surface water brings the virus into the wild. That is why the only wild birds that have tested positive so far have been water birds and a hawk, which probably fed on a sick chicken.
The spread of the disease didn't at first spread along normal bird migration routes, but along human trade routes. Apparently people are still shipping infected chickens and their feathers and eggs from place to place, and that’s introducing the disease into new places. Now the disease does seem to be following wild bird migration routes, too, and that means that birds like cranes and ducks that winter in Asia and cross over the Bering Strait to Alaska may carry the disease here. There are plans to kill and test a great many of those birds this year.
It would be at least a year or two before the disease reaches backyard songbirds. Even if a backyard bird got sick, it would be very easy to protect yourself from the disease. Whenever you find a dead bird in your yard, pick it up with your hand encased in a plastic bag. Turni the bad inside out to enclose the bird without touching the bird (the way people pick up dog poop). Dispose of the bird carcass in the garbage. DON'Tthrow it in the woods where pets or other animals could eat the contaminated carcass. The people who have become sick so far have not just picked up sick or dead chickens; they’ve plucked or butchered the bodies of the infected birds, greatly increasing their contact with the sick birds' blood and infected organs.
The good news about avian flu is that it probably won't develop into a pandemic where a lot of people get sick—at least not while the disease is so dangerous. The reason people get so very sick from this virus is because it attaches to us is very deep in the lungs. Even if the virus was capable of going from person to person, people can't cough out viruses from so deep within their lungs. Before it could cause a genuine pandemic, the virus would have to mutate two different ways: to attach higher up in the respiratory system, AND to change so it could be transmissible from one person to another. But if the disease does mutate to attack higher up in the respiratory system, it probably won't be nearly as dangerous as it is in its present form.
I am very worried that people will overreact and kill birds in a panic. A great President of the United States once said that the only thing we had to fear is fear itself. If we can focus on careful science (1) to figure out how to help sick people survive this kind of flu; (2) to create a vaccination to protect ourselves and farm animals from getting the disease in the first place; and (3) to figure out how to prevent people from letting infected animals and their parts get from place to place, then we'll have a better chance of conquering the disease than if we just panic.
From: Indiana
Q: Our first robin of the year arrived last Saturday. We feed cornmeal/suet mix and the robin apparently remembered where that was! This robin has already chased away our resident cardinals and any other birds that come to the feeder. We also have bluebirds checking out nest houses. Should we try to discourage this robin from building a nest in our yard? I am afraid he will be so territorial that we will lose our bluebirds. Thanks much.
A: After the ground is nice and thawed, you might stop feeding the robin at least until after its eggs hatch. It won't trouble the bluebirds near their houses (assuming you’re not feeding the robin close to the bluebrid houses) and you can make a special bluebird feeder designed for cavity-nesters. Look here for some examples.
From: Ohio
Porter Center for Science and Math
Q: We have a robin that has been returning now for at least 3 years. It constantly pecks at our sliding glass doors. What can I do to discourage it? I have tried black paper hawk shaped cutouts. Perhaps my hawks aren't authentic enough. The windows face the east. Thanks! Carolyn
A: Your robin thinks its reflection is another robin. The simplest way to deal with the situation is to tape paper or cardboard over the whole window, on the outside, for three or four days until the robin gets busy enough with other things to forget about the "intruder" on its territory. If it's too hard to cover the whole thing, you might try papering over the area where the robin has been actually hitting, and hanging shiny helium balloons nearby. Most birds are frightened of helium balloons, probably because they act so different from things that birds encounter in nature: the balloons seem to fall up!
From: Colman, South Dakota
Q: It's March 14th, it's 7 degrees here in eastern South Dakota, and I've got a pair of robins who arrived last week during a warm spell. Will they stick around? I've got suet cakes and dry, high-protein dog food for them to eat.
A: The first robins of spring behave as winter robins, living comfortably in a flock and feeding on berries and other fruits, when the temperature drops. Sometimes a bad storm from the north or a bad drop in temperatures will send them south. Usually they’re just moving wherever they need to go to find enough food to get through the hard time. Robins don't normally eat dry dog food. They eat suet occasionally. They’re more interested in mealworms and other insects as their source of protein, and berries as a good source of vitamins. Some individuals do adapt to other food sources.
From: Swift Current, Saskatchewan, Canada
Q: I have had lots of strong wind around my area and the Robins nests were getting knocked down. Will this affect them re-nesting next year?
A: Robins have the strongest nest site fidelity, meaning the strongest urge to return to the same nest site a second year, when they succeed in bringing off babies. When nests fail because of wind, rainfall, predators, or other causes, the robins usually try a new site the next year.
Q: Can Robins build nests WITHOUT mud if mud isn't available?
A: Robins tend to select nesting territories where worms are available. The right habitat usually provides both mud for nest making and a supply of food. During periods of too much rain or not enough rain, robins will delay nest-building.
Q: My Robins came back too early and has been singing. There is still snow on the ground. Is this normal?
A: Robins usually return when the average day-night temperature is 37 degrees Fahrenheit. This is the average; some days will be warmer, some colder than that. And when a male arrives and finds a good territory, he can't help but sing. Sometimes after a male starts defending a territory a sudden bad weather system will send him off to a robin flock eating fruit. But when he can find enough food on his territory again, he'll be back. Singing is evidence that he’s got plenty of food in your yard and is ready for spring, even if the snow makes it look like winter.
From: San Diego, California
Q: I live in San Diego, CA in a community called Clairemont. We are about five miles west of the ocean. We have never seen any robins by my house even though we have trees behind my home. However, years ago when I worked at Clairemont High School in the early 1980's, I would see robins returning in the spring. And this would only be in a certain area where there were trees planted between the outside classrooms. I don't know if they continue to return to this area. Can you give me any information why we don't have them all around San Diego?
A: San Diego is fairly arid, so robins can't count on a steady supply of worms. They tend to live near trees for three reasons: shade, fruit, and a supply of caterpillars. The type of trees in an area, and the softness and moistness of the soil are critical for robin survival.
jnorth@learner.org
Q: When robins are feeding on worms one sees them lean their head close to the ground and become very intent. What sense are they using to locate the worm: sight, hearing or something else?
A: Robins are using sight. They are peeking into the tiny burrows worms make. A scientist named Frank Heppner figured this out with a really cool experiment. You can read about it here.
From: Houston, Texas
Q: Normally in January, we see robins in flocks numbering in the hundreds. This year was different. The few we saw were one or two at a time. Could the drought conditions we have been experiencing in Southeast Texas have caused the birds to go somewhere else?
A: Definitely. Drought prevents trees from producing much fruit, which is a major source of food for robins. And dry soil causes worms to burrow deeper down, where robins can't get them. Fortunately, since weather conditions vary widely from one year to the next in many places, individual robins don't return year after year to the exact same place. Their flocks wander around in search of places where food is most available right then.
From: Titusville, Florida
Q: As Robins leave Ontario, Canada in the fall, they do not seem to gather in big groups like some other birds. Do they travel in big groups? The past two winters, I have seen hundreds on our golf course in Florida. They stay for about one week, and then they are gone again. Where do they spend winters? Would our location be a feeding place or a meeting place? We have lots of holly berries here. How fast do they travel?
A: Ontario is a huge place. I've seen large flocks of robins flying along Lake Superior in the Fall, up in Thunder Bay, Ontario. Your specific area may be richer in the kind of habitat suitable for breeding than for autumn feeding, in which case you’re seeing just small family and local units that join larger flocks in places where more autumn food is available.
In winter, robins tend to remain in areas until they've depleted the food supply. Golf courses are beautifully green, but sometimes the pesticides and fertilizers used to maintain those green lawns kill earthworms. And golf-course ponds can be very contaminated from chemical runoff. So robins may eat the fruit in the trees for a while, but they'll want a more balanced diet that they find elsewhere.
Meeting places for robins tend to be feeding places as well. That’s why so many birds are gathered there.
Robins move about throughout the winter. They depend on what’s called patchy food supplies, and have no fidelity to a single place. How fast do they move? Flocks can easily move over 100 miles a day, but sometimes they notice a good fruit tree just five miles from where they started and stop for a few days again.
So there are no simple answers to any of your questions! Wouldn't you think such a common backyard bird would be easier to understand?
From: Lexington, Massachusetts
Q: This is not a question. March 21st is the Equinox in the Northern Hemisphere. So, somewhere in the explanation, it states that it is an equal night and day all over this planet. I beg to differ as it is fall in the Southern Hemisphere. Please clarify.
A: March 21 is the spring equinox in the Northern Hemisphere, and is the fall equinox in the Southern Hemisphere. After March 21, days grow longer north of the Equator and shorter south of the Equator. But for both halves of the globe, March 21 is the equinox.
From: Austin, Texas
Q: Here are a series of questions about the color of robin's eggs. Why are robin's eggs blue? I am told that some animals can see color and others are less able to see color. Can Robins see color? How about blue? Here in Texas, cowbirds lay eggs in the nests of other birds. Does this happen to robins? Is this why the eggs are a special color? What kinds of research have scientists done regarding the color of robin's eggs. Thank you.
A: I know of no birds that can't see color. Most birds see more colors than we do! Scientists have done a lot of research on bird egg color, but their studies seem to produce more questions than answers. The color of eggs is partly determined by pigments that are secreted by the female as her body is secreting the calcium-based shell, and partly determined by the nest materials or soil where the eggs are laid; sometimes these can stain the eggs, changing their color. Why are robin eggs blue? Scientists have noticed that birds that nest in cavities and other dark places have eggs that are all white. This may help a mother bird entering the nest see them so she won't accidentally step wrong and damage them. Birds that lay their eggs in open nests on the ground tend to be camouflaged—the egg colors match their background or surroundings to better conceal them. What might be the advantage of having blue eggs? Hard to say! They may match sun-dappled leaves. It's a mystery that no one has really found a satisfactory answer to.
Cowbirds usually choose smaller species as host parents to raise their babies. A Song Sparrow would have a much more difficult time tossing out a huge cowbird egg than a robin would! Cowbird eggs often look quite different from the natural eggs in the host nest. In Europe, where cuckoos parasitize nests, the cuckoo eggs match the host's natural eggs surprisingly well. That may be because cuckoos have been parasitizing nests for a much longer time in Europe than cowbirds have here in America. Host species in Europe have had a longer time to evolve the ability to recognize and toss out eggs that look different; in turn cuckoos have evolved to lay eggs that match their hosts. Interestingly, in America a single female cowbird may choose the nests of dozens of species for depositing her eggs; in Europe a single cuckoo tends to lay her eggs only in the nests of the one species that raised her.
From: Ferrisburgh, Vermont
Ferrisburgh Central School
Q: What makes the robin's egg blue?
A: The blue is caused by pigments in the females’ oviduct, the tube that the egg passes through on its way out of her body.
From: Hinckley, Illinois
Hinckley Elementary
Q: What causes a robin to migrate north? How do they know when it is the right time?
A: The shortest day of the year in the northern hemisphere is the Winter Solstice, around December 21. After that, days start growing longer. At first you can hardly notice it, but by mid-January, its getting more obvious. Longer days tend to make birds feel restless. While temperatures stay very cold, robins stay in their flocks and focus on getting enough food. As temperatures get a bit milder, they don’t need to shiver so hard and so they need less food each day, and they get more and more restless. Restless flocks just start moving more, and their inner urges send them toward the latitude where they hatched out—where the sky just looks right to them.
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