|
When
Will Robins Reach the End of the Trail?
Making Predictions Using the Plant Hardiness
Zone Map
Background
Short-distance migrants, such as American robins, are usually not winter-hardy
enough to stay in northern regions during the cold winter months. Robins
normally winter in the southern U.S., from Washington to California and
into northern Mexico. Unlike hummingbird or oriole migration, robin migration
is tightly connected to weather.When will the robins reach their northernmost
breeding territories this spring? To let us know, and to ensure that the
first robins to reach far north are properly noted and welcomed, Journey
North has set up northern observation posts where observers will report
their first robins. While we wait to hear from them, you can make your
own predictions with the help of a special map that shows climate bands.
In this lesson, students will consider climate as a factor in robin migration
and use the plant hardiness zone map to predict the FIRST robins and the
robin SONG for Journey North's 20 Northern Observation Posts.
Activity
1. Click to enlarge the righthand map below
and explain that Plant Hardiness Zones divide the United States and Canada
into 11 areas. The divisions are based on a 10 degree Fahrenheit difference
in the average annual minimum temperature. (You may want to discuss
these terms to be sure students are clear about their meaning.) For example,
the lowest average temperature in Zone 2 is -50 to -40 degrees Fahrenheit,
while the minimum average temperature in zone 10 is +30 to +40 degrees
Fahrenheit. The colors on the map give a picture of "climate bands"
and show how cold it gets. Growers and gardeners use this information
to know which seeds will grow well in their region. NOTE: When you click
to enlarge the map, the top of the new page includes a link to an enlarged
map key. You will find it helpful to print out the key.
2. Locate your community on the Plant Hardiness Zone Map
and find the minimum temberature ranges for your zone on the key. Discuss
when you see your first robins, and when you hear the first true songs
of males back on territory.
3. Print out the map of the 24 northern observation posts.
Locate them on the Zone map. Explain that students will use the climate
information on the Plant Hardiness Zone map to make predictions about
first robins and songs for each of the posts. You can download reproducible
recording sheets to help keep track of predictions:
4. Keep an eye on the weather maps and upcoming robin
reports for news from the northern observation posts to see how your predictions
turn out!
Try
This! Discussion
or Journaling Questions:
- Audubon officials say their annual Great Backyard Bird
Count (done in February each year) has indicated bird species that usually
live year-round in Canada and the northern U.S. are spreading south.
What are some reasons why this might be happening?
|