American Robin Migration Update: April 6, 1999
Today's Report Includes:
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
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,
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:
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:
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.
The next Robin Migration Update will be posted Tuesday, April 20, 1999.
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