The Magic of Monarchs

Butterflies
Migrating monarchs – via Flickr

This past week I saw on the news footage of millions of monarch butterflies arriving in California and into the forests of Michoacán, Mexico.

It is wonderful in the true meaning of the word – something filled with wonder. I am filled with wonder and awe whenever I look up at the night sky and consider the universe. I get that same sense sometimes when I am walking through a forest, watching a river or at the ocean, or standing on a mountaintop looking at a faraway horizon.

Those butterflies swarming like a swirling paint palette of orange and black also seem magical.

Cooler temperatures make the monarchs cluster together until it warms and they can fly again. 

Their migration began in the northern U.S. or Canada and they have traveled as far as 3,000 miles to reach more temperate winter homes.

Migration is pretty amazing. We know some things about how species make the journey. We describe it in human terms sometimes – they have built-in “GPS.” They have the knowledge from parents who passed along the knowledge. With monarchs, it is not parental knowledge. Their short lifespans preclude that. Only about one out of every five generations of monarchs migrate. Birds do back and forth migrations, but monarchs are the only butterfly species known to make a two-way migration.

The Sun has played a role in human navigation and also for monarchs. We don’t understand exactly how it works for these butterflies. I kind of like that it is still a mystery, but scientists do want to know. After all, the Sun moves, and to use it to navigate you also need to know what time of day it is when you are looking at it. How do monarch butterflies keep track of time?

Researchers have discovered that most monarchs take to the skies when the Sun is 57° to 48°. That is their window of opportunity whether they are leaving Canada or Kansas. They don’t seem to have some built-in clock but their antennae do seem to play that role in some way.

But all the science takes some of the wonder out of this. As much as I love science, the idea of researchers putting microchips on butterflies and painting or clipping antennae to study how their brain reacts in captivity to a false Sun seems cruel.

It is also sad how climate change and deforestation are negatively affecting monarchs and their migration. A recent report from the Mexican government and the World Wildlife Fund states that the amount of forest occupied by hibernating monarchs in Mexico went from nearly 15 acres in the winter of 2018 to 7 acres in 2019 to only 5 acres in 2020.

Summer Is Not Over But…

It’s Labor day weekend. Summer is not over but many people mark an unofficial end of summer with this weekend. Schools in the northern part of the U.S. head back to school and colleges start the fall semester. Families are less likely to go on vacations or even head to the beach for a weekend.

I see from my blog stats that people are once again clicking on past posts about autumn and even those that discuss the weather lore for predicting the coming winter.

I hope you will continue to enjoy summer weather for a few months, no matter what the calendar tells you. Southern hemisphere readers can really look forward to summer.

Did you know that according to the “meteorological calendar” autumn begins today, September 1, for those of us in the northern hemisphere?  The meteorological calendar uses our Gregorian calendar and splits up the four seasons into three clean month blocks to make it easier for forecasting and comparing seasonal statistics.  That makes spring March, April, May; Summer: June, July, August; Autumn: September, October, November; Winter: December, January, February.

Most of us stick to the astronomical calendar which tells us that September 22 is the start of autumn. That is when the autumnal equinox, when night and day are roughly equal length, arrives.

One of the many signs that summer is moving into autumn is the migrations of species to warmer areas.

Monarch on rough blazing star. Photo by Debbie Koenigs/USFWS.

In mid-August, I started to see some adult monarchs who are partway through their lifecycle heading south in their autumn migration.

According to the USFWS, these monarchs are different from their parents, grandparents and great grandparents who completed their life cycle in four weeks. Those monarch migrated north, resulting in four generations this summer. The ones we are seeing are members of the generation that migrates south, often called the monarch “super generation.”

It’s about 3,000 miles to Mexico guided by the sun. They do about 50 miles a day. These delicate creatures sometimes ride thermal air currents and can be up a mile high.

What triggers their migration? They are not so different from other creatures – including people – who consciously or unconsciously look for signs around them that the seasons are changing.  The monarch butterflies sense the decreasing day length and temperatures and even the aging milkweed and other nectar sources triggers the birth of the super generation and their migration.

These super monarchs live eight times longer than their parents and grandparents. That is still only 8 months, but they will travel 10 times farther.

They will conserve energy by storing fat in both the caterpillar and butterfly life stages. They will wait to lay their 700 eggs until spring.

Monarch on swamp milkweed

Monarchs are totally dependent on milkweed. Plant some! Don’t pull out the milkweed plants! The plant is their nursery for the caterpillars who only eat this plant, and the flowers are a nectar source for adults. Their population has decreased significantly over the last 20 years.

There are projects to improve habitat for pollinators, including monarchs, like planting native milkweed and nectar plants that are local to your area. Gardening organically minimizes your impacts on pollinators and their food plants. Become a citizen scientist and monitor monarchs in your area. Educate others about pollinators, conservation, and how they can help. Learn how you can play a role in reversing the population decline and save the monarch.