Number of Monarch Butterflies Down as They Leave Michoacan and Head through Texas

The Monarch butterfly population status report was made public this week. Given last year’s perfect storm of bad conditions–late freeze, historic drought, raging wildfires–butterfly followers were expecting bad news.  It was.  Overall Monarch butterfly numbers were down 28%.

Monarch butterflies are leaving Michoacan and heading to....Texas!

Monarch butterflies are leaving Michoacan and heading to Texas.

The much anticipated document issued each spring by the World Wildlife Fund assesses the overall health of the migrating population by calculating the physical space they occupy in the Oyamel fir forests of Michoacan, Mexico.  This year, the millions of butterflies occupied a little more than seven acres.   The average is almost 18 acres.

Monarch Watch, a Monarch butterfly monitoring program based at the University of Kansas at Lawrence, put a positive spin on the findings, tagging the report “relatively good news,”  given dismal expectations.  “Nevertheless, this represents another low population – one well below the long term average near seven hectares,” the citizen scientist and academic collaborative reported.

The report was issued especially late this year, on March 15, an act that aggravated scientists and left others wondering why it took so long.  “The international scientific community is baffled why it  took so long for WWF and others to release the colony data for the current overwintering season,” wrote renown Monarch butterfly scientist Dr. Lincoln Brower in an email to the DPLEX list, a butterfly listserv followed avidly by

Monarch butterflies are on the move in Texas

Monarch butterflies are on the move in Texas

butterfly enthusiasts and scientists.  “The long delay actually hampered research planning for important molecular studies by the scientific community.”   Brower challenged WWF officials on the reasons for the decline, suggesting that while crazy weather and habitat loss tied to herbicide tolerant crops are factors, illegal logging and “severe degradation of the Oyamel forest ecosystem has been and still is occurring.”

Interestingly, a spokesperson for PROFEPA, the equivalent of the Environmental Protection Agency in Mexico, said earlier this year that illegal logging at the roosting grounds had been contained to 3.7 acres.

The good news is that the butterflies have left their Mexican roosts and are coming our way. Reports from Twitter, Facebook and butterfly listservs detail FOS (first of season) sightings of the migrating butterflies flitting through Texas, laying eggs on native and tropical milkweed plants, delighting gardeners and butterfly fans.

Kip Kiphart, a volunteer for the Monarch Larvae Monitoring Project at Cibolo Nature Center in Boerne reported via email that he found 27 eggs on his native milkweed plants in Bergheim, Texas this week.  Others chimed in:   “Saw two in my  yard in southwest Austin,” said Helen Boudny Fremin. “We’ve had a couple in Marathon this past week,” reported Mathew York.  “Pretty sure I saw a Monarch butterfly yesterday,” tweeted Mike Leggett, an outdoor writer in Austin. Those migrating Monarchs presumably will visit San Antonio’s local colony over at the Museum Reach Milkweed Patch for some mixed company nectar sipping.

Monarch butterflies have left Michoacan and been spotted all over Texas

Monarch butterflies have left Michoacan and been spotted all over Texas

Texas has been called the “most important state” to the Monarch butterfly migration because of its strategic location between the roosting grounds and the milkweed beds and nectar prairies that serve as hosts and food sources for the famous insects.   Millions of Monarchs pass through Texas each spring and fall as they make their multi-generation migratory flight from the Mexico to Canada and back.  Spring in Texas is a critical time for the Monarchs, as they seek out milkweed plants–their host, and the only plant on which they will lay eggs–to continue their multi generation migration north.

With our exceptional and well-timed South Texas rains this winter, the Monarchs will have plenty of wildflowers for nectar and milkweed  for reproducing. Time to plant more milkweed in our gardens to get the migration off to a good start.

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15 thoughts on “Number of Monarch Butterflies Down as They Leave Michoacan and Head through Texas

  1. Cannot wait for them to arrive in NC! But then again, I hope they wait until there is some milkweed sprouting….I’ve not seen the first sprig, even though we have had record high temps.

  2. Pingback: Here they Come! Monarch and Other Butterflies Passing Through, Laying Eggs and Sipping Nectar | The Rivard Report

  3. Great read, Monika, thanks.
    Re rains, I just saw this at

  4. I keep reading the pleas to plant milkweed to help save the monarchs but the A. viridis in my DFW garden is only barely poking up from the ground right now. Every year it seems that by the time the plants are large enough to support caterpillars, the monarchs have already passed by. Should I focus instead on early bloomers for nectar?

    • If you’re not a native plant purist (and I’m not), you can have Asclepias curassavica in your yard or in pots. Monarchs gravitate to it. Read the article on our resources page to see what you think. Good luck!


  5. Monika,
    My Monarch caterpillars are doing well! I have noticed lately though that there are a pair of Green Aeroles hanging around the caterpillars. Will the Aeroles eat the caterpillars? The caterpillars are pretty big and it seems unlikely, but I really don’t know. Looking forward to your response. thanks.

    • HI Cathy,
      Thanks for writing. I’m afraid I don’t know what you mean by Green Aeroles? Is it an insect?


        • I don’t think the lizards will eat them, but I supposed it’s possible. I would bring them (the caterpillars) inside for safe keeping if you have any doubts.
          Let us know what happens!


  6. Pingback: Here they Come! Monarch and Other Butterflies Passing Through, Laying Eggs and Sipping Nectar | Rivard Report

  7. I have seen about four caterpillars on my milkweed right now. The milkweed is covered with aphids and black insects, etc… Will these insects eat the monarch eggs and/or caterpillars. The milkweed at our elementary school (zilker Elem.) and there is quite a bit, does not seem to have any eggs or larvae. We are worried that this is all we are going to see this year. What do you think? We do a big study of the life cycle of the Monarch every year. I would love for our school to be part of a study with you.

    • Hi Ann,
      APhids don’t eat Monarch eggs but they attract wasps, ants and beetles. Their excrement is sweet and known as “honeydew.” It ends up smothering the plant and making it unhealthy, in addition to attracting many Monarch predators.
      So what to do? You can spray them off the plant with a strong gush of water from a hose or spray bottle. I prefer to squish them between my fingers (it will leave your fingers all orange).
      A few aphids are fine and suggest a plant that has not been sprayed with pesticides; but too many degrade the plant and are not a good situation, so try to rid the plant of them as best you can.
      The other option is just bring the caterpillars inside and raise them as I describe in the article. That way you can witness the whole process, which is so educational and such fun.

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