Spring 2009
Teaching Suggestions
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Why do robins hop?
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How many times will a mother robin use the same nest?
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Why do robins molt in the fall just before they migrate south?
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Laura
Erickson |
From: West Virginia
Q: Why do Robins hop?
A: Most songbirds and other birds that spend a lot of time in trees are "hoppers." Springing forward in a hop is an efficient way of getting from branch to branch. But on the ground, hopping takes a little more energy than walking or running. So robins are one of the few species that can do both!
Q: How long is the incubation period, and how long are baby Robins dependent on their parents?
A: Robins incubate for about 12 - 14 days. The record was 7 days--this must have been during a warm spell when the eggs could stay warm even when the mother was off the nest feeding. It takes the babies about 2 weeks to leave the nest, or "fledge," and then they usually stay with their parents for two or three weeks after that. The father continues to feed them while the mother starts incubating a new brood of eggs.
From: Missouri
Q: Where do robins go when they die? We hardly ever see dead birds, or robins unless there is a cat in the neighborhood. Sometimes we see dead babies if they fell out of the nest, or if they got attacked on the ground before they could fly. It just seems like there are millions of birds, but not many dead ones.
A: When people have pesticides sprayed on their lawns, they sometimes DO find dead robins laying on the lawn during the next day or two. But usually when robins get sick, their slow flight and confused actions make them easy for predators to find, so the robins get eaten rather than simply keeling over dead. Robins weigh only about 2 1/2 to 3 ounces, so when one does die of a sickness, it doesn't take long for scavengers to make it disappear!
Q: The robin updates talk about large groups or flocks of robins migrating. They say most of them are males. Where are all the female robins? Don't the males and females spend the winter together or in the same areas?
A: Although males and females certainly do spend the winter in the same general areas, some males remain farther north than the majority of robins, and all males become restless to leave earlier than females. So for most people living in Canadian provinces and in the central and northern states, the first robins they see in spring are males.
From: Minnesota
Q: Why do robins molt just before they are about to migrate south?
A: They molt so they will have fresh feathers for their flight. These fresh feathers will also be very good for insulating them from the winter cold.
Q: Has anyone ever reported seeing a midget robin?
A: No. Sometimes "midget" eggs are laid, but these are usually infertile. Adult robins seem to be just about all the same size, but under their feathers their weights can still range from 64.8 - 84.2 grams.
From: Saskachewan
Lethbridge College
Q: I was walking to school one day in the fall and I heard a Robin singing its heart out! Why was this Robin singing in the fall?
A: For some reason, some frogs and some birds have a burst of song in the fall. They don’t sing as strongly for so many hours in a day, or for so many weeks. Not so many individuals sing, as do in spring, but some do sing. As their bodies prepare for migration and migratory restlessness grows more powerful, their mixed-up hormones may give them a burst of energy to do something unusual—like singing in fall! Also, day length in September is about the same as it is in March, and although days are getting shorter in fall, they’re close enough to spring to confuse some birds.
Q: I love the song of the Robin early morning and early
night. But why does their song have an echo at these times that’s
not heard in the afternoon? At least I haven't heard the echo in the afternoon.
A: Their early song, called the dawn song, is sung with
extra excitement. It’s sung much faster than the mid-day song. What
you’re hearing as an echo is really the two separate sounds produced
by the two branches of the syrinx—the part in a
bird comparable to our larynx, where the voice is produced. Our larynx
is in our trachea—the tube running from our throat to our bronchial
tubes. In birds, the syrinx is right where the trachea branches into the
two bronchial tubes, and they produce sound from both branches, so can
make harmony or echoes with their own voice! The robin you’re hearing
is making the two different sounds with just enough of a time delay to
give it an echo sound, making its dawn song fuller and more energetic.
Q: I found a Robin using a nest without mud! Why didn't
they make one out of mud?
A: Robins usually use mud in nest construction. When
a robin can’t find mud, it has two choices—to nest in a different
place, or to build the nest with different materials. After a robin succeeds
in raising young from an “odd” nest, it may continue to build
that kind of nest again, even if mud is then available.
From: Minnesota
Q: How many times will a mother robin use the same nest?
A: Usually just once. If she was successful in raising young in a nest, she’ll often build a new floor for that nest to raise another brood, but some robins just use the same nest a second time.
Q: Do baby robins migrate by themselves? How do they
know where to go?
A: After a brood of young robins fledge (leave the nest),
the mother starts building a new nest and laying new eggs even as she
still spends most of the time each day attending to those fledglings.
The father spends all day with the fledglings and leads them to a roost
at nighttime, where they join with other fathers and fledglings. When
the mother finishes laying a new clutch (which takes usually four to six
days after her new nest is built), she starts incubating and leaves the
fledglings to their father’s care. When the new eggs hatch, the
father leaves the fledglings on their own and returns to feeding the new
nestlings. Those fledglings hang out with the other fledglings from their
nighttime roost, finding fruit trees and worms and being sociable, and
every night the fathers join them in the roost. As the last broods are
done being raised, the mothers join these flocks. So by the summer’s
end, robin flocks contain birds of all ages that start to wander, looking
for new feeding areas that provide some worms and fruit. The young birds
hang out with these restless flocks, moving from place to place in search
of food, mostly headed in a southerly direction. They don’t have
to know where to go on their own because of their need to associate with
other robins.
From: Florida
Q: I live in a rural, southeast corner of Orange County, Orlando, Florida. I usually see the Robins in our yard by this time of year but have not spotted any as of yet. I have seen them begin to pass through our neighborhood as early as November through February in years past. I was wondering if there is some change in the environment, weather, migration path, etc. or is this a usual pattern of change?
A: During winter, robins are very nomadic. In some exceptional places they may appear year after year, but their wandering may also change dramatically sometimes because of weather and food patterns farther north. For example, if fruit is unusually abundant in Georgia and Tennessee in one fall and winter, the bulk of robins might not bother to migrate as far as Florida. As temperatures grow milder, more robins may winter farther north. But as of now, the biggest February flocks of robins are usually in the St. Petersburg area of Florida, according to the Great Backyard Bird Count.
From: Rockledge, Florida
Q: Robins always come to our house by the hundreds in late January and February for our cherry, laurel and palm berries. We have had a dry year but we are always on their path. Our family is so disappointed. The migration map seems to show no sightings of robins south of Ormond Beach, Florida. They did not come to us this year. Why? (Rockledge Florida is 20 miles south of Kennedy Space Center.)
A: If your robins found abundant fruit before they reached your area, they may have stopped sooner than usual. And they usually avoid places that are having dry years because fruit is more abundant in wetter places. They’re hard to predict, which makes more special the winters when they DO show up special.
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