While you are undoubtedly familiar with the monarchs’ fall migration, here are 10 interesting factoids you might not know:
1. The Monarchs aren’t going the way of the Dinosaur anytime soon, but…
There is reason to be concerned about the future of the monarch migration as we know it. This chart by Journey North is a sobering look at the alarming decline of what was once a booming migration:
2. The Monarch Population Estimate is Only…an ESTIMATE⁉️ 😲
After an extended fall migration (warm weather) in 2017 and reports of large numbers of migrators entering into the overwintering grounds, many were convinced this would mean a healthy increase for the eastern population in 2018.
Their impressive arrival was followed by many positive reports on the ground from those who lived near the wintering grounds and those who were visiting them. Many were surprised by the bevy of butterflies that were fluttering through the sanctuaries…a sure sign of good news to follow?!
When the population estimate was finally announced last February, I (and many others) were puzzled to learn the estimated overwintering population was down 20 million….hmmmm 🤔
As spring 2018 unfolded, the first Journey North reports from Texas were that they were witnessing perhaps the greatest coastal migration for monarchs…in decades! An increase in sightings followed all through spring and summer…
It’s become clear the 2017-18 monarch population estimate wasn’t even close to accurate, so now we’ve got to stop and wonder…Why? A few questions to consider:
Was the population concentrated in an area that wasn’t covered during the count? Are there additional winter populations located between the southern US and central Mexico? Is there political motivation (endangered species list inclusion) for underreporting? How accurate are current counting methods?
Regardless of the reason, it appears safe to say the eastern monarch population has been growing in the right direction since its low point in 2013, including an estimated 144% increase for the 2019 season.
Your gardening and raising efforts are making a difference…even if the ‘numbers’ don’t always agree. 😒
Keep doing what you’re doing, and let’s challenge the science community to figure out a more accurate method for measuring the true state of the butterfly population.
3. Fall Blooming Plants can Attract Hundreds of Migrators!
Some luck is involved in enticing mass monarchs through your garden gates, but by planting flowers like Mist flowers, Liatris ligulistylis, and the Mexican sunflowers in the following butterfly video, living this dream is a distinct possibility…
4. Monarchs Roost on Trees in Clusters that can Number in the Thousands
This culminates in the roost to end all roosts at their Mexican wintering grounds where they number in the millions. Coastal California also has overwintering roost sites in the thousands. The trees are literally covered in a blanket of monarchs.
Back in the northern US, monarchs also form nightly roosts as they make their way down to Mexico. This one was formed in our Minnesota garden:
5. Some of the Western Monarchs DO Migrate to Mexico
It was reported at the Monarch Biology and Conservation Meeting (2012) that butterflies tagged out west have been found on the forest floors of the Mexican wintering grounds.
6. Monarch Butterflies Glide in Upper Air Masses called Thermals to Conserve Energy
They ride these thermal waves all the way to Mexico. They fly at speeds ranging between 15-25 mph…one tagged butterfly was recently reported on Journey North to have traveled 265 miles in one day.
Recent flight study results posted on journey north revealed that a monarch with 140mg of fat to burn could fly for 44 hours when flapping, but 1,060 hours when soaring and gliding!
7. Monarchs Mysteriously Arrive at the same Remote Wintering Grounds Season after Season
Strangely, none of the returning monarchs have ever been to the wintering grounds before. If there are maps from ancestors in their genetic coding, imagine what this could mean for your monarch butterfly garden at home. Once they find you…
8. The Mexican Forest is NOT a Safe Haven!
It’s estimated that more than 15% of the overwintering population will fall victim to predators that pluck them like berries from trees. These predators include black-backed orioles, black-headed grosbeaks, and black-eared mice. See how these predators are a danger to monarchs in two ways:
9. The Monarchs that Migrate to Mexico in Autumn are the Same Ones Returning to Lay the Foundation in Spring
These mature ladies will be seeking fresh milkweed in the southern US to start a new season filled with the magic of monarchs.
10. Migration Monarchs are Massive
While the wingspan of earlier monarch generations is generally 3.5-4″, most of the migrators have wingspans over 4″…no doubt they’ll need the super-sized wings for the long journey ahead…
Did you know these 10 things about the monarch migration? What are your favorite facts and factoids about the great fall migration? Post your Monarch Migration questions and comments below: