Mass Migration in California
But Were They Monarch Butterflies?

March 15, 2005
Suddenly, migration reports began to appear like a rash on the map on the edge of the Mojave Desert, near San Bernardino, California. One person reported a "massive swarm of monarchs" and a boy said "about ten butterflies bumped into me." Here's how others described what they saw:

Comments from Observers in California

(Click map for more comments.)

But were they monarch butterflies?

Try This!

Do YOU think the massive migration in California was of monarch butterflies?

1) First, find out what monarch butterfly migration looks like in the spring. Read:

2) Explain whether you think the California butterflies were monarch butterflies or not. Give evidence to support your view.

3) Then read what the experts had to say:

National Science Education Standards

  • Use data to conduct a reasonable explanation.
  • Think critically and logically to make relationship between evidence and explanations.
  • Science investigations involve asking and answering a question and comparing that to what scientists already know about the world.
  • Scientists develop explanations using observations (evidence) and what they already know about the world.

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