The 2019 Monarch Migration Report
Updated on September 13, 2019
The Monarch migration is now surging across the Midwest and here in the Northeast, with reports of huge numbers and impressive flights this past week, particularly along the Great Lakes.
I’ve transformed this post, first published as a forecast in August, into a progress report. As it turns out, my initial forecast, certainly here in the Northeast, was spot on. We’re seeing more Monarchs in migration than we have in many years.
Examples include reports of “many thousands” passing by the north shore of Lake Ontario near Toronto on September 8, and 4,000 at the tip of Pt. Pelee National Park on Lake Erie on September 4. Here in Vermont, hawkwatchers at Mt. Philo in Charlotte reported Monarchs heading south in numbers “too many to count” on Thursday, September 12.
I’ll be out today (13 Sep) to update conditions in Vermont’s Champlain Valley. But needless to say, we’re having a banner migration across much of the Northeast. We should be seeing good numbers heading south well into October, with stragglers into November.
Nobody tracks this great autumn event better than the folks at Journey North (where you can follow the fall migration) and Monarch Watch (which runs a citizen-science tagging program). Each is a source for my own forecast here. I’ll part ways, however, with Monarch Watch, which had predicated migration in the Northeast would be on the “low side” of normal years. I predict it will be on the high side. Very high.
My evidence for this good season had been crawling on milkweed from Maine to Vermont and elsewhere online. We’ve been lousy with Monarch caterpillars here in Vermont. And up until early August, I was seeing summer Monarchs breeding to produce the migratory generation.
Assuming we have normal temperatures, reasonably healthy milkweed, and no major outbreaks of predators, parasitoids and parasites, we should see lots of Monarch adults in New England and much of the Northeast this fall. (By the way, all sorts of organisms attack Monarch eggs, caterpillars or pupae, including nematodes, mites, spiders, lacewings, wasps, fire ants, tachinid flies, hemipterans, and a panoply of microbes.)
Yes, my evidence is anecdotal. Very much so. But my gut is strong. And it’s hard to argue with lots of people reporting online across northern New England that they’re seeing more caterpillars than ever before — or at least in a very long time. I’m among them. iNaturalist has been lit up with larvae from New England and Quebec since August 1. Those caterpillars, munching your milkweed right now, will become migrants.
Elsewhere, Monarch Watch is predicting good prospects for a “normal” migration across much of the Monarch’s range and a “robust” winter population. In the Pacific Northwest: “After the lowest overwintering population in California ever recorded, the western monarch population is struggling to bounce back,” according to the status report, which predicts another poor year for the western wintering population. In the Southwest, they’re expecting a “low to modest fall migration,” according to the report, but the breeding was mixed across the West this year, so observers remain hopeful for Monarchs in the area this fall.
So, unless I’m wrong (and I may very well be), I’m preparing for a Monarch monsoon here in New England. Some welcome news, for a change, on a planet we’re warming and destroying by many means. And with Monarchs and so many other wild things at risk or imperiled, it’s nice now and then, even rejuvenating for us, to pause and enjoy nature before it’s gone. Let’s do that. (Heck, they even announced a cure for ebola this week!)
You can give back to Monarchs: I’ll be tagging them by the hundreds this fall. You can also report your sightings to Journey North or iNaturalist. But by all means, as I advise in my essay Butterflies and Joy, take some time to sit with these animals and witness their spectacular journey to Mexico. It might, at least for a while, make you feel good — and ever more eager to carry on the fight for nature.
Butterflies and Joy
Two hundred orange butterflies in a meadow of purple wildflowers. It reminds me to slow down, lose the gadgets and find the joy.
"To Pimp a Butterfly"
Sorry, Kendrick Lamar. You may have won a Grammy, but you got beat in the "pimping" by a lawn-care company.
Migrate or Die
The fate of late-season Monarchs in migration on the East coast. Many may not make it to Mexico.