Friday, March 5, 2021

2021 outlook for monarchs in the Adirondacks

monarch butterflyThe size of the overwintering population of Eastern monarch butterflies was just released on Feb 25, and the number shows yet another decline (to a total of 2.1 hectares/ 5.2 acres; details are shown in the figure below). What does this mean for the Adirondacks this coming summer?  Monarchs were abundant in the Adirondack region in 2018, just as they had been decades ago, but 2021 will be a year of many fewer, just as it was in 2020 and most recent years.

Monarchs are in decline because of multiple threats throughout their life cycle: the loss of milkweed because of industrialized agriculture in their main midwestern breeding area; logging of the overwintering forests in Mexico; drought and loss of nectar sources due to climate change; and increasing severity of killing storms.

Recently the US Fish & Wildlife service declared monarchs to be “warranted but precluded” for listing under the Endangered Species Act. That decision is well explained at: It means that the federal government will take no actions for the time being to reverse this decline even though the current figure of 2.1 hectares is much below the estimated number of 6 hectares required to sustain monarch migration.

overwintering chartThere is uncertainly, of course, about what we will we see this summer. Will the severe cold in Texas of the past two months further depress this year’s monarch abundance by slowing the growth of milkweed and nectar sources needed for the northward migration? Will summer weather in the Adirondacks be moderately warm, which is ideal for monarchs to lay many eggs and increase the numbers we see? Although our area is not the region of most reproduction, milkweed grows well here. Will warmth in the fall delay the return migration, giving us late sightings into October?

Here’s a reminder of when we’ll first see monarchs. Those butterflies that survive the winter in Mexico begin migrating northward in February and March and lay eggs in Texas and the southern tier of states. Monarchs that emerge from those eggs complete the northward migration into the breeding region of the central U.S. and southern Canada. Their offspring spread out in multiple directions where there is milkweed, including the Adirondacks, and that is the generation we usually first see. Additional generation(s) add to overall abundance, so we see more monarchs in August than at any other time of year.

Keep an eye out for monarchs this summer. Those you see reflect underlying changes in the environment around us.

The above figure of overwintering monarch abundance is courtesy of the Monarch Butterfly Fund ( Photo at top by Ernest H. Williams


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Ernest Williams is an ecologist who taught at Hamilton College for 34 years. He has a summer camp on Twitchell Lake.

16 Responses

  1. Nathan says:

    modern herbicides, mainly glyphosphates are killing off most milk weed. milk weed likes to grow in “disturbed soil” that is mainly ground thats been dug up in recent years. Thi is most common along edges of corn fields. i started growing milkweed patches and i have two totaling about an acre of land. I discovered one important factor for monarchs, they like semi-shady patches of mild weed. i have one patch that gets about sun from dawn to dusk, i rarely find monarch catapillars in it. I started a second patch that is half shade to 3/4 filtered sunlight( under some loose pines). there i find monarch catapillars by the dozens in summer. I rototill the land about every 3 years, and i brush hog or mow the patch down when seeds goto fluff. this knocks down competing plants and keeps seeds in area.
    Want to help the monarch plant a 10×10 patch in flower bed, or any semi shady part of your land, give the guys some food to multiple , plants some flowers and bushes for feed, butterfly bush works great. Give nature a helping hand

    • Boreas says:

      I agree. I have been sowing milkweed species around my property for the last decade. Last year was a bumper crop of Monarch caterpillars. Unfortunately, most of my property is wooded, so it limits how much I can plant.

      • Ernest Williams says:

        Thanks to Nathan and Boreas for suggesting the creation and maintenance of milkweed patches. Don’t forget nectar sources. Habitat is important, and milkweed is also a good nectar source. Please avoid using pesticides, and if you obtain plants from garden centers, make sure they have been grown without pesticides. But plantings should be with native species. Although butterfly bush is attractive to insects, it is not native; better nectar choices include purple coneflower, sweet pepperbush, ironweed, joe-pye-weed, and a number of other native plants.

        • Boreas says:


          I have about 1/4 acre worth of wildflowers and bushes with a preponderance of pollinator species. I love coneflowers, but my deer love them more. If I don’t spray them with noxious repellent weekly, they are decimated by deer. Deer and pollinators also love my garden phlox which grow prolifically in my gardens.

          My gardens are mostly shaded and very sandy, so many species do not do well here, like joe-pye weed and a few other native species. I continue to sow what grows and is deer-resistant. Perennial “wild” sunflower does pretty well here as does lupine and viburnum. I recently planted some ninebark and spirea that pollinators seem to like. Deer like the ninebark.

          I am also lucky enough to have a small brook running through my property. Although 95% of it is under heavy canopy, the section out by the highway is open to the sun. A decade ago the village installed a water line and disturbed the area. With the help of the DEC’s Buffer In A Bag program, I am trying to naturally re-vegetate the area to maintain a riparian character with an emphasis on native fruit-bearing shrubs to help birds. Much of my milkweed has been planted in this disturbed “wetland”.

          I also recently became a NWF Certified Habitat sponsor. It is pretty simple to certify your property as wildlife-friendly. I did it primarily to buy a sign to install by the road so that passer’s-by become aware of their project and consider doing the same. My next project is to turn at least 50% of my remaining lawn into pollinator habitat. I have purchased my last lawnmower.

  2. Vanessa says:

    This is indeed a real bummer :(:(

    But per above, growing milkweed in your yard is a great way to help, yup! We even grow a bunch in our city park.

    Also, a beautiful fictional look at this topic is Barbara Kingsolver’s “Flight Behavior” – it’s a whole story besides for butterflies, but lends wonderful backdrop to the science.

  3. chris cohan says:

    ADKAction with Paul Smith’s College, Lake Placid Land Conservancy and The Wild Center, successfully increased native pollinator plantings throughout the BlueLine over the past years. 2021 plans are for free distribution of milkweed and wildflower seed; expanded plant sale this spring of the best pollinator plants at great prices as well as other initiatives.

    Please get involved. A little bit by many will help to save and expand Monarch populations. Spread the word and spread native pollinators, too.
    See this link for more details-

    • Boreas says:

      What I would like to see, but don’t know how to go about it, is a program developed by P-S or someone else with an easy way for some of us to approach private landowners and local governments to allow or mandate planting wildflower/pollinator species on recently disturbed land. Construction like powerlines, pipelines, reclamation, roadwork, etc. are all met with sowing often non-native grass species. Why not specify say 1/4 of those projects to be sown with native pollinators? The only problem would be the cost of the seed and the delay in mowing (if even necessary) until a killing frost. There are acres of potential wild plantings in my little hamlet alone. Any native pollinators are better than turf.

      • chris cohan says:

        Boreas- Where do you live?

        Private landowners and municipalities are becoming more aware and approachable.

        Municipalities, I believe, are more receptive when this is framed as a way to for them to save time/money/resources by reduced mowing. Then only mow right of ways after monarch have left. Also, they are able to claim they are environmentally sensitive while being economically conservative.

        We have found these arguments are best made by local residents/voters to their local municipalities. ADKAtion has online resources and wants to encourage efforts like yours. I am not in a position to confirm what they may be willing to do. So, please contact ADKAction about your local effort and opportunities.
        Like the saying goes, ‘Many hands make light lifting.’

        • Ernest Williams says:

          In our region, roadside (and field) mowing is fine up until early July and then again after mid September. Monarchs aren’t here in any numbers before early July, and adults produced from any caterpillars present after mid to late September will not survive the migration. Mowing in some patches in June can actually be beneficial, too; cut milkweed regrows, and regrowing milkweed stems are more attractive to egg-laying females than are old stems. Best of all is a mosaic of patches of young and old milkweed. Get your highway departments to understand this; they can mow early on and late in the summer to keep roads open but stop during the 2 1/2 month monarch season of July, August, and the first half of September.

        • Boreas says:


          I live in the Town of Chesterfield.

          I will take your suggestion and look at ADKAction. Thanks for the help.

  4. Tom Vawtee says:

    Thanks for posting this here. You are certainly correct that the damage to the migration has largely been done before Monarchs reach the Adirondacks in the summer. Thanks also for pointing out that Milkweed is common here, and it’s probably not important to plant more. What we can do is refrain from destroying the abundant Milkweed we have. Locally, here in the Town of Webb (Old Forge area), the Highway Department, under Superintendent Casey Crofut, holds off mowing Milkweed from roadsides and other Town lands until most of the fall migrants have left.

  5. chris cohan says:

    It was really great to read that Town of Webb understands proper mowing to maximize milkweed value! Here’s to other municipalities, Counties and State doing the same.

  6. Charlie Stehlin says:

    This is so very sad! The bees are having problems, bats, birds…. wolves lately! I’m not religious but I sure do hope there’s an enlightenment soon! Thank you all for your efforts. We need more good souls that care enough to take action!

      • JB says:

        You know, Boreas, there is an interesting rabbit hole that you can go down about the Holocene megafauna extinction related to the focus on North American megafauna being wiped out by humans, while there is relatively little talk of human influence on the concurrent extinctions in Europe. And then there is the whole thing about Clovis tool culture (from some of the first Native Americans) resembling closely the concurrent tool cultures from France–and that, combined with greater Atlantic sea ice extents, is the foundation of a theory espoused by a few fairly well-credentialed archaeologists that the some of the first Native Americans may have actually been European (the large-statured Dorset who went extinct circa 1500 in the Eastern Canadian High Arctic come to mind). I remembered you had mentioned Euro-centric bias a few articles back…

        I, too, am anti-lawnmower to a large extent. There is a place for that type of thing immediately around the house, but it is a travesty in my opinion to destroy all of that native habitat, instead opting for non-native grass seed! There is a whole other history there–what do you think that non-royalty did before lawnmowers? They certainly did not have manicured lawns!

  7. chris cohan says:

    ADKAction plant sale ( )features a few deer resistant plants for sun or shade.
    Blue Wood Aster, Columbine and Beebalm all handle part shade well and have been shown to be deer resistant.

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