This website last updated December 1, 2014

Fall Migration is ending, but some are still here!

While most migrating monarchs have reached their winter homes, our warm weather has invited a late generation to stay in the lower deserts of the southwest. As long as we do not have a hard freeze, we may be lucky enough to see them flying and nectaring on flowers. Please report all monarch sightings so we can learn more about those who spend the winter here. Join the Southwest Monarch Study team!

You asked, we listened. Through your encouragement, We are now a federal 501(c)(3) non-profit organization. Your donation helps us purchase tags and print educational brochures as well as offer milkweed seasonally. We are grateful for your financial support of monarch conservation in the southwest. Donations are now tax deductible.

Over 300 Citizen Scientists have tagged monarchs for the Southwest Monarch Study and you can, too! Look at our map of Wild Monarch Recoveries. There is so much more to learn! Join a tagging trip or tag on your own. No effort is too small - we never know who will discover a new piece in the monarch puzzle. How to tag? Take a few moments to read this link. Tagging season usually begins around August 15 and continues through October.

Contact to reserve your tags today! Keep an eye on our FB page for impromptu taggging events when monarchs are moving in to new locations.

Visit /SouthwestMonarchStudy for up to the minute monarch news!

The Southwest Monarch Study is researching the migration patterns of monarch butterflies in Arizona and the Western United States. It was once believed that monarch butterflies East of the Rocky Mountains flew to the mountains near Mexico City for the winter and monarchs West of the Rockies flew to the coast of California. Through Fall tagging in Arizona and the Southwest (Nevada, New Mexico, Southern California deserts), we have learned that this is not always the case.

There is much more to learn about the wild monarch migration in Arizona and throughout the Western states. If you love monarch butterflies, consider joining our study.

Our Mission:

  1. To identify and describe the migration and breeding patterns of Monarch Butterflies (Danaus plexippus) in the Western United States.
  2. To provide a meaningful research project for citizen scientists of all ages.
  3. To encourage and monitor Monarch Butterfly conservation.

How do we do this?

  1. We tag Monarch Butterflies during their Fall migration from August through November.
    See how to tag a Monarch. Click here
  2. We monitor milkweed populations throughout the West. Why is milkweed important? Click here
  3. We look for habitats that attract Monarch Butterflies.
  4. We actively support the North American Monarch Conservation Plan (NAMCP).
  5. We encourage the development of monarch habitats and Monarch Waystations. For information for planting in your area, download one of our publications (PDF reader needed):
  6. We provide educational programs to raise monarch awareness.

Who can participate?

Everyone! All ages can learn to tag monarchs!

Since 2004, citizen-scientists have tagged thousands of monarch butterflies in Arizona. Some of these monarchs flew to Mexico, and others to the coast of California. We have discovered monarch breeding habitats and we are also learning about monarchs who spend the winter in Arizona. We are very excited by these recoveries (a recovery is a tagged monarch reported in a distant location), but we need more. Come and join us in some of the most beautiful parts of Arizona and the Western United States, have fun, and contribute to the understanding of one of the world's most spectacular natural phenomena, the monarch migration.

If you are interested in joining this exciting research, or would like more information about our recoveries, email:

Data Access Policy

Unless specified otherwise, all data Copyright 2014 Southwest Monarch Study Inc.

The Southwest Monarch Study Inc. (SWMS) encourages researchers to share our findings in appropriate publications, based in whole or in part on SWMS data. Researchers accessing the data should realize that some data may not have been vetted, and may contain inaccuracies. Therefore, SWMS requires that anyone using the data for scientific purposes contact SWMS for permission to use any data. SWMS will contact you and discuss the validity of the data you request. If your request is approved, you will receive written permission to use our data.

To request permission to use our data or for other information please contact us at

Through the National Audubon Society's "Pennies for the Planet" campaign, Southwest Monarch Study has been awarded $7,000 to be used for the monarch butterfly overwintering habitat at Rio Salado Habitat Restoration Area in Phoenix. If you would like to be part of this exciting project, email Gail Morris, project coordinator.
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Unless specified otherwise, all data Copyright 2010-2014 Southwest Monarch Study Inc. Information from this site may not be copied or distributed without prior written approval from Southwest Monarch Study