SPRING FEVER

Spring temperatures can be used to help forecast some signs of spring.

Your class can test whether it's true that robins arrive on your lawn when

the "isotherm" reaches 36 degrees.

Here's how:

Measure the daily high and low temperatures every day for seven days.

(You can do this using a special thermometer called a "maximum/minimum

thermometer". If not in stock at your local hardware store, ask them to

order one for you.) At the end of 7 days, average these 7 daily averages.

The result is the "isotherm" for that week. When the isotherm reaches 36 F,

robins should appear on the lawn! Here's an example for one fictitious week:

Day M T W Th F S S

H/L 40/20 32/20 29/15 26/15 34/20 40/20 42/28

Av. 30 26 22 21 27 30 35

To calculate the isotherm for the above week, just average the above averages:

(30 + 26 + 22 + 21 + 27 + 30 + 35) divided by 7 = 27 degrees F.

No robins yet!

Masses of robins usually move north as the temperatures reach the above averages, but some will be "early birds". To standardize observation methods when testing the isotherm theory, watch for robins to appear on the grass. (Obviously the isotherm theory won't apply to robins that over-winter in your area.)

Extensions:

1. Watch for the first earthworms and note the isotherm when worms appear.

2. Contact a school in a different city and see if you can predict the arrival of their

first robins and earthworms based on temperature. (You can find high and low temperatures of their city on the Internet or in the newspaper.)

3. Test this rule of thumb:

"It will snow 3-4 times each year after the first robins return."

Is this true where you live? Let us know at:

jn_rule@informns.k12.mn.us

4. Remember to report the FIRST robin you see this spring to:

jn_robin@informns.k12.mn.us

Where to Report OVER-WINTERING vs. MIGRATING Robins

A) As has been mentioned, this has been an unusually warm winter in many

regions and robins have remained in places they are not usually found

during the winter months. This is why the "Winter Robin Round Up"

conducted by 7th graders at Wisconsin's Valders Middle School

is so important.

Report robins that have WINTERED in your region to them at:

ddill@earth.execpc.com

B) Remember that you must watch for robins regularly so that the FIRST

robin you report is a meaningful observation.

Report sightings of FIRST robins to: jn_robin@informns.k12.mn.us