Fall is when princely butterflies migrate to Mexico
If there ever was a fair weathered friend, it is the Monarch Butterfly.
You might have noticed a lot of them out and about in mid-to late-September or so and as the weather gets cooler, but after that, not a trace.
They head for Mexico.
Well, seeing as they make the few thousand-mile trek with their own wings, you could say Monarchs really earn their siesta.
Pickering Creek Audubon Center in Easton is one of several parks and other organizations that take part in a “citizen science” Monarch Tagging program through “Monarch Watch,” with their naturalist Mary Helen Gillen leading groups to help collect data.
Butterflies lay their eggs only on popular pollinator plant, milkweed, and grow quickly to larva (commonly non-scientifically called caterpillar to three year olds) to a pupa hanging in chrysalis (commonly, a cocoon hanging from a tree).
If you thought your little ones grew up too fast, think about this- the rate of growth of an egg to a caterpillar is the same, Gillen says, as “an infant turning into the size of a school bus!”
Butterflies in the generations that will do the migration have larger sized wings, usually over a 4-inch wingspan while non-migrating generation will have one of 3.5-4 inches.
The migration itself truly is a marvel.
Temperature cues as the weather turns cooler tells the cold-blooded butterfly masses it’s time to start heading south and the Monarchs will follow the same routes as their great-great grandparents, though no butterfly from the former generation is still around to lead.
The Monarch mystery goes even deeper, as not only are they journeying to a destination they have never been to before, but they can be tracked veering around a mountain that is no longer there when they fly past the Lake Superior area.
To help better understand the migration, the Monarch Watch database was launched in 1992 by long time Monarch researcher Dr. Fred Urquhart, and accessible to “citizen science” at the University of Kansas.
Taggers, who can be professionals or enthusiasts, from Canada to Mexico “tag” the butterflies with small stickers around the size of a pinkie finger.
Each tag is unique, and the tagger would record date and gender of the butterfly tagged in the field and record it in a national database, www.monarchwatch.org.
Maryland tagging typically happens in late September, while other tracking hotspots such as California have the Western Monarch Thanksgiving Count, and later the El Correo Real count in Northern Mexico.
Ideally, the same butterfly would easily flutter through the yards of multiple trackers, but in reality, a departure date from the north and a date down south is a lucky break as annually around 1 in 200 Monarchs tagged will be recovered.
Still, you can also track some of the stories of butterflies and their fate on the Monarch Watch website, such as a Monarch found the day after being tagged was discovered to have traveled 265 miles in one day.
While other butterflies and moths do head toward warmer weather in the colder months, Monarchs set themselves apart as their trip is specific and not simply following available food sources.
Siesta in Mexico
It’s not just happenstance the Monarchs end up somewhere south of the border- they actually go to roost in the same few acres and in some cases, the same grouping of trees in the transvolcanic mountains in central Mexico.
The fir and pine trees there are a popular hotspot and one branch alone can hold as many as 15,000 butterflies.
Rather than attempting to count the millions of butterflies, scientists simply use an estimate of covered acres.
After weathering through winter, the Monarchs will head back north, with generation by generation inching their way back to Maryland and beyond.
At least two generations will simply fly north, lay eggs, and die.
These populations can also be tagged to add to the critical data.
How can you help the Monarchs?
Planting fall blooming native plants that provide nectar is a great way to keep butterflies nourished on their trip.
With natural sources becoming further and further apart, this becomes more and more important. The seemingly small amount of fat stored in their abdomen powers them through the thousands of miles trip and they actually end up plumper with “vacation weight” than when they departed for their voyage. With recent major weather events damaging plants and wildlife habitat, the planting of additional nectar supply will be more important than ever.
In Mexico, especially in the sanctuary areas, efforts are being made to decrease logging.
The diminished coverage in surrounding areas from logging can also impact the temperature and coverage to the finicky flyers.
Slight temperature changes can wipe out Monarchs, such as the 1.5 million late migrators who perished in an unusual ice storm in Mexico in March 2016.
In addition to Pickering Creek, Environmental Concern Inc. in St. Michaels, who lead the Mid-Atlantic Monarch Initiative, also host a variety of Monarch centered courses in from spring all the way till winter, covering everything from butterfly gardening to rearing to tagging.
Monarchs have long been the most popular and publicly recognized butterfly, and considering their amazing migration, they are rightfully the “king” butterfly.