|
|
CMSE Online Front
Page |
|
"Birds of a feather flock together." This old proverb isn't literally true most of the year, but for most birds it is true in the winter. On a gray winter day, with a cold wind sweeping across our back yard or school yard, we may not see any birds at all for long periods of time. And then, all of a sudden, we see quite a few. If your classroom has a feeder, your students are likely to notice that often there are no customers, but sometimes six or ten birds will show up at the same time. Birds flock in the winter for two main reasons. First, food is obviously harder to find in the winter. Most of our winter birds fall into one of two groups: berry-eaters (waxwings, bluebirds, mockingbirds) and seed-eaters (blue jays, chickadees, sparrows). For both groups, food resources are usually scattered and short-lived. To find them, the birds work together, traveling in flocks and calling continuously to each other. The other reason is less obvious to us, but painfully obvious to the birds. Birds are much more vulnerable to predators in the winter, because the trees are bare, there aren't as many places to hide, and what food there may be is often exposed to the view of passing hawks. There are several species of hawk in our area during the winter, as well as the American kestrel (a small falcon). But for small birds, the most dangerous predator is probably Cooper's hawk, a medium-sized, long-tailed, swift-flying hawk that tends on pounce on birds as they feed on or near the ground. Cooper's hawks often concentrate in suburban areas during the winter, visiting feeder sites in hopes of a quick meal. Flocks are a good defense against predators, because in a large group somebody is likely to spot the hawk in time to sound the alarm. Furthermore, if a hawk swoops in and everyone flies at once, either everyone will get away or all but one will get away. Keep your eyes open, and try to open your students' eyes as well. You'll see flocks of snowbirds crossing the school grounds, small groups of bluebirds flying through the woods, big flocks of waxwings swarming around berry-laden trees, mixed flocks of sparrows at your feeder, and noisy flocks of chickadees, titmice, and kinglets in the pines. If you have a classroom feeder, there are opportunities for students to make observations and collect data about these flocks. What birds appear together? Which ones come singly to the feeder? Are there birds who only appear when other birds are present? What causes all the birds to fly away at once sometimes? Can you distinguish between the different notes the birds use, and identify the alarm notes? In the depth of winter, most of nature is dormant. Birds and people are the most conspicuously active animals, and it seems we keep one another company until the spring comes again. Internet Sources
|
Cedar Waxwing
Eastern Bluebird
White-throated Sparrow
Cooper's Hawk |
FEEDBACK: We'd be happy to have your comments and suggestions.
Posted January 2, 1997. Features remain online as long as they remain current; they may be updated if new information becomes available.
Copyright © 1997, Center for Mathematics and Science Education. Teachers have permission to duplicate this page for use in teaching their own classes. All other rights reserved. You are welcome to link to this page, but do not copy its contents.
|
http://www.unc.edu/depts/cmse/nature/wntrbirds.html Center for Mathematics and Science
Education PHONE: voice (919) 966-5922; fax (919) 962-0588 |
CMSE Online Front
Page |
