10 Things You Might Not Know about the Magical Monarch Migration

Each August through October, masses of monarchs embark from the southern reaches of Canada on a journey that will take them 2500 Miles to remote mountain treetops in central Mexico. Millions of overwintering monarchs were discovered roosting there for the first time in 1975.

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:

2017 Monarch Butterfly Population Estimate in Millions
Weathering the Storm

2. The 2016 Fall Monarch Migration…the smallest in years?

Monarch enthusiasts across North America were rejoicing in February 2016 when it was announced that 200 million monarchs were overwintering in Mexico last winter…up from just 57 million the year before!

But then the unthinkable happened…

It was early March 2016 and the first monarchs had just started migrating back to the US, while most were still gathered in the Mexican forest…an unfortunate twist of fate. A wicked, wintry storm tore through the overwintering colonies. A season of high hopes was instantly toppled.

Population loss estimates were all over the place, with Mexican officials putting storm related deaths at 6.2 million butterflies.

The 2016 season started slow as a 🐢  covered in molasses…it was obvious the storm had served a devastating blow to the already-struggling monarchs. 😩

But as the season progressed, monarch sightings increased dramatically. An unseasonably warm fall produced an extra generation of migrating monarchs, which helped boost the 2017 overwintering population numbers to almost 75% of what they were before the storm

This shows that monarchs are a resilient species and that our gardening and raising efforts are making a difference…

Let’s hope the 2018 winter season in Mexico supports those efforts!

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 flowersLiatris 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.

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…

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