Good News on Monarch Butterflies, But Don’t Get Too Excited

So the good news is that there are a lot more Monarch butterflies roosting in Mexico this winter than there were a year ago. Monarch populations are measured by the size of overwintering colonies in the mountain forests of Michoacan. This year, they are covering a little over 6 hectares (or about 15 acres), a 144% increase from the 2016-17 winter, when just 2.48 hectares were occupied.


To me and many other gardeners, it did seem like there were more Monarch in the garden last year – now this perception has gotten some validation. This year’s numbers are the highest they’ve been since the winter of 2006-07, according to the above graph from Monarch Watch.

Unfortunately, one year does not make a trend, and the trend still looks negative over the longer term. Scientists quoted in a New York Times article noted that this year’s numbers are mainly due to 2018’s favorable weather conditions. The Monarch population could take a big hit if the weather turned less hospitable.

DSC_0714 Monarch
Monarch on Butterflyweed.

Still, we should never dismiss good news, especially these days. Monarch Butterflies are still imperiled by habitat loss, insecticides, etc. The work of conservation by government, non-profit organizations, and individual gardeners (plant more Milkweeds!) should continue and intensify. The New York Times quotes University of Guelph ecologist Ryan Norris on the new numbers: “It buys us time, but that’s all it does.”

29 Comments on “Good News on Monarch Butterflies, But Don’t Get Too Excited”

  1. Monarch butterflies are so common here that they have preserves. Sadly, they congregate in groves of exotic eucalyptus trees that were grown for lumber a very long time ago. While congregating in the eucalyptus groves, the neglect to pollinate many of the native flora that rely on them. When I was in school, I briefly lived in a neighborhood known as Monarch Grove in Los Osos.

  2. I’ve only been paying attention to the issues for about five years, but it seems clear to me that public awareness is increasing substantially: both about the needs of the monarchs, and the need for more native plants for pollinators generally. This past year, I certainly saw more migrating monarchs than I ever have. It was touching, really, to think of how delicate their entire life cycle is, and how easily it could be disrupted.

  3. The two hurricanes during their fall migration — Florence and Michael — may have lowered numbers a bit on the eastern route. Late- and long-blooming salvias, especially ‘Indigo Spires’, seemed to make a difference here. The monarchs finally laid eggs on the common milkweed after three seasons of only milkweed tussock moths. Hope conditions are good for them again this coming season; I’ll beef up the salvias further with such a great excuse to grow them.

  4. Jason, a relief to read your post, because I didn’t think there were as many monarchs here in Central Kentucky last year as in 2017. I work in three certified monarch waystations, one is my own garden. Let’s hope for a good overwintering in 2019/2020.

  5. The Monarchs do have a difficult life. I hope this years trend continues onward and upward. All Butterflies have a difficult life. The D@#% wall is going right through the National Butterfly Center in TX. Sigh~~~

  6. Good news indeed! I have faith that some of the increase is due to public awareness and the helping hand that individuals and municipalities are giving by planting (and not getting rid of) milkweed as well as creating monarch/butterfly friendly gardens/corridors.

  7. Hello Jason, I hope the dramatic increase is not just a one-off, but the start of a new trend. At the very least, it provides for some “headroom” for buffering a poor weather season. It’s a stunning change compares to just five or so years ago when the number was a 10th and perilously low.

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