The Monarch Butterfly Migration: A Species Survival

March 21, 2024

How To Be Part Of The Extraordinary Migration Of The Monarch Butterfly.

The irony of our situation this year has not escaped me! We, humans, are stuck at home. All of us are counting the names of people we know or world leaders who have caught the COVID 19 Virus. For a vicarious travel experience, and well suited to the interests of any gardener- we can follow the exploits of the Monarch Butterfly. Here is how to be part of it all.

Update On Monarch Butterfly Status-December 2020

On December 15, 2020, the US Fish and Wildlife Service announced that while the declining Monarch butterfly population deserved endangered status, it would not add them to the list this year. Here is a link to the blog maintained by the organization Monarch Watch with their assessment. If you love to follow the Monarchs on their journey, you may find it interesting.

Status Update The North American Monarch Butterfly Spring 2021

In February and March, the monarch begins to emerge from hibernation, seeks out a mate, and starts the long journey home. On the way, they first need fuel for the trip; they are looking for some nectar to eat and some milkweed to lay their eggs on. Every territory they cross has its own kind of milkweed, they don’t care, they just need milkweed, it has to be milkweed.

The problem is, milkweed is declining. Blame anything you want; more humans, more agriculture more construction, the weather. Less milkweed shows up as fewer Monarch butterflies! This winter was not a good one.

The Mexico overwintering population that we see emerging now is reduced by 26% from last year! Source, Monarch Watch. The California population that travels from west of the Rockies north to the southern California coast is the worst! We are told that the population of California Monarchs is under 2000. Source, Xerces Society. We also hear that there are now fewer Monarch butterflies in the golden state than there are Starbucks!

The Monarch Butterfly Migration: The Survival of a Species

The monarch is the only insect we have ever found that can migrate as larger animals do. This is a complete migration; it’s a spring and fall, north and south round circuit. Each tiny butterflies’ trip can be as long as 3,000 miles.

Monarch Butterflies In Flight

In some parts of the world, the monarch lives in warm climates. In North America, they spend the summer in cool territories as far north as Canada but move for warmth and food to places in the sun.

I live in South Florida, and, sadly, my seasonal neighbors are hesitant to trave this year. Not the monarch butterfly! They are on the road now, in a migration that began in mid-august. We know this because we are tracking them. Large volunteer organizations dedicated to the monarch are keeping records, These records are fueled by the sightings of citizen scientists all over North America. People like us are all watching, from Canada to Mexico.

How Can This Happen?

We are talking about a creature that spans three to four inches, weighs about half a gram, and has a brain about the size of a pinhead. Its average lifespan is two to six weeks. Yet it crosses North America in a complex migration that NONE of its millions of participants have ever done before! Yes, birds live for years, they know where they are going. Not one butterfly, ever, on their migration has done the trip before.

We are trying to get to Italy for a belated anniversary visit. We want to experience the Veneto; mountains, art, wine, Palladio; the works. What the monarch is doing is like climbing in the Dolomites with a blind guide who has never been there before!

How Do They Make This Work?

Well, we are not totally sure. Loads of people, from scientists to farmers watched but couldn’t figure it out. We began tagging monarchs with little numbered stickers in the 1950s but did not even retrieve a full distance traveler until 1975.

Think of it this way, we put a man on the moon before we figured out what the little butterfly was up to!

Navigation Biology

The uncanny mechanism by which the monarch navigates has baffled scientists for years. Neuroscientists are working on understanding how they travel such long distances so accurately.

The monarch has an internal compass that integrates the time of day and the sun’s position on the horizon. They use large, complex eyes to monitor the sun and they have an internal clock on the antenna.

The antenna and eye send information to the brain using two neural mechanisms. The balance between these two mechanisms helps the butterfly decipher the right direction.

Both of these mechanisms can reverse themselves, which explains why the monarch can travel in two directions.

Essentially the butterfly has a navigation system not unlike that used by the early navigators in wooden ships long before we figured out longitude.

When Do The Monarch’s Hit The Road?

If you are reading this before the end of November you will see them soon. If it is wintertime, the spring migration north will start in March. We are fortunate to have several months in which we can see the monarchs in flight.

How Can I Be Part Of It?

The life of the monarch is so elusive and their status along with that of other essential pollinators is so at risk today; that we have a great need to monitor and protect them.

Journey North

Citizen science is a way to encourage us to be involved. Journey North is a major organization that uses the observations of all of us, right where we live, to watch and report on the monarch migration phenomenon. They put the sightings of people who report them on an interactive map that you can follow on their website.

On this site-Journey North-monarch migration– you can follow the migration through its various stages. Pick a circle and click on it, you can read what the butterfly spotter said and where he saw the butterflies.

On the home page, you can follow all of the news in the migration, as it happens and it tells you how to sign up if you want to report your sightings. If the kids are bored this could make your day!

Monarch Watch

Monarch Watch is a valuable organization which actually captures, tags and releases monarch as they fly. (People who do this say that they can do a catch and release in 30 seconds!) This means that they can tag a butterfly with a code indicating its origin. Recaptured, temporarily, the butterfly reveals the place it was first, caught and tells us about its journey.

The first butterfly was tagged in the 1950’s. So far 1,000,000 monarch butterflies have been tagged. Of these 16,000 have been captured along the way and at their final destination. Today the butterflies are still telling us the story of their journey.

Monarch Watch publishes a map which shows us the direction of the flight. Here it Is.

What We Learned From The Butterfly Tagging

If you like a good mystery, the journey of the monarch is a dilly. In Canada and The US, we have always known we have these brilliant orange and black butterflies in the warm seasons and then they just took to the air and disappeared!

Likewise in mountainous parts of western Mexico, their residents welcomed the monarch into their lives in winter. Here, instead of being spread out as northern people saw them, they hung in mountain forests in great walls of wings on large trees. Then in spring, they took to the air and just disappeared!

Fred Urquhart, (1911-2003) a renowned monarch researcher in Canada, devoted his life to solving the mystery and devised the first tagging system. The organization he founded became Monarch Watch. There is a charming film about his lifelong devotion to his cause.

This video is the trailer for the film. It is a nice one-minute introduction with really helpful imagery; you can watch the whole film on you tube. It is well worth your time.

Flight Of The Butterflies

How does this help me take part?

If you are along any of the routes shown on the map you can spot some monarchs in flight or even, taking a break in your backyard.

How can I encourage the butterflies to stop along the way?

Plant some milkweed!

Plant some milkweed. Go to your local garden center, buy your own local variety of milkweed. Ask for plants not treated with pesticides. Put them in a sunny place in your backyard. The monarchs will smell the milkweed from a long distance. You will also attract them with nectar-producing flowers. The flower nectar, stored in their bodies as fat is the fuel they need to survive the journey.

To survive the trip the butterflies need lots of the milkweed plant and it needs to be everywhere. The national academy of science dates the decline of both monarchs and milkweed to the 1950s. It continues today.

Why Is This So Important?

A Flagship Species

The butterflies have been on earth for the last 175 million years, and they bring us a unique value as we try to live on a healthy planet. Because the insect is both beautiful and delicate, it is an ideal forecaster of the health of the world we live in. Scientists use them as indicators of biodiversity and call them a Flagship Species to signify their importance.

This is because butterflies throughout the globe are appreciated by the people who live near them. They are today’s application of the “canary in the coalmine”. When the butterfly population anywhere on earth is failing people notice it! They are telling us whenever something is wrong in the environment.

The Butterfly’s Value As A Pollinator

Monarch Butterfly Busy
Monarch Butterfly Busy

Three-quarters of the world’s flowering plants and 35% of the world’s food crops require animal pollination to reproduce: USDA. We know that the bee is essential to pollination but the butterflies are responsible for 20% of global pollination. They are important in our lives.

So, Is There A Problem?

Oh yes! Throughout the world, we are losing pollinators. Pollinators are suffering the same losses as other species. They are disappearing because of habitat loss, degradation, and fragmentation. They suffer from the same disease and pollution as other creatures.

The monarch’s specific problem stems from habitat loss; milkweed, which grew everywhere in the pastures of my childhood, is disappearing all over the world, and the monarch can’t reproduce without it.

Enter The Backyard Gardener

Here we have a prime example of the value of digging in the dirt. It doesn’t take much. Plant your garden just as you like it. Grow what you want, enjoy the pleasure and the exercise, and the beauty that you create. Just add something for the pollinators. This is pretty easy; add flowering plants for nectar, some branches for shelter, and plants for the butterfly to lay her eggs on.

People like to talk about making a difference. Well planting for the pollinators is not grandiose but anybody can do it and it works!

What The Butterfly Needs

Bee Balm

This is Bee Balm, an all purpose pollinator plant which will attract bees, butterflies, and hummingbirds. Not only is it a garden “Hat Trick” but when our early American ancestors rashly dumped the British Tea into Boston Harbor they learned to make tea out of this!

It is native to much of North America and should be easy to find in zones 3-9.

In terms of dinner, the butterfly is eclectic and open-minded. Plant a variety of colors, shapes, and sizes. If you like them the butterflies will too. In terms of laying eggs, however, the butterfly is specific. Each butterfly variety has a select few plants, often just one on which it will lay its eggs.

The Monarch will only lay eggs on milkweed. It must be milkweed, which contains a poison. The butterfly caterpillar doesn’t mind. He chews it up and it protects him from predators who avoid him like the plague. ( I can find only two bird species which will eat a monarch caterpillar.)

The interesting point is that as the monarch covers as much as 3000 miles in a trip, and it happens twice per year, they will use all of the many varieties of milkweed they encounter along the way. It can be any milkweed, it just has to be milkweed!

So add some milkweed to your garden.

Anybody Can Be Part Of This!

This is a cost-effective, easy, useful, productive, environmentally beneficial hobby! Yesterday I watched a video about a girl who raises monarch butterflies in her fifth-floor apartment. She has potted milkweed and some flowers on her balcony. When the monarchs lay their eggs she brings the caterpillars indoors and raises them in containers. She has a film of the little caterpillars grabbing milkweed leaves with their sharp little claws and chowing down!

When the butterfly exits the hanging crysalis she waits for it to dry off and carries it out to the balcony and it moves from her finger, on to the world.

The Benefits Of Helping Pollinators

There are a few opportunities in our lives to just step in and make a difference. Here is an example. Where we live, rapid growth and development are removing the habitat for the once, nearly extinct, Florida panther. A male panther requires 100 square miles of territory to roam, the female needs 60. Not many people can individually help the panther to remain part of the ecosystem.

Pollinators are essential to our food chain, but they are tiny. You can save a lot of pollinators with a few pots of flowers on the patio. Where else can you have that power?

A Milkweed Tip

Monarch Caterpillar
Monarch Caterpillar

The pretty little striped caterpillars are gluttons! A single caterpillar, before entering the chrysalis to become a butterfly will eat an entire one-gallon milkweed plant. That’s about 200 leaves. Your milkweed plants will each be filled with caterpillars. This feeding habit is the equivalent of a seven-pound newborn eating 1400 pounds of baby formula in two weeks!

It is a challenge to keep up with them. This is a procedure we worked out for our garden. Decide how many milkweed plants you can put in your garden. Buy three times as many. If you have room for four, you need to have twelve. Don’t plant the rest. Just stick the pots in the garden. You can either hide the pots behind other foliage or sink them in the ground.

Keep the other plants in a sunny spot where you do not expect butterflies; A screened area is ideal, you can use a vegetable screen or tunnel. You can also put them in an all green space which is not likely to attract butterflies. As the caterpillars denude your plants, remove them to your storage garden to regrow. Keep swapping. You will get several regrowths from each as they are a hardy plant.

Otherwise you will be like John Henry and owe your soul to the garden center!

How The Migration Works

Map of Monarch Migration from US Fish and wildlife

The Two Monarch Migrations

In North America there are two great migrations of monarch butterflies.

The West Of The Rockys Migration

This is the less complex one. Primarily, beginning in Oregon and Idaho, assembled like great orange clouds, the butterflies soar southbound to San Diego, Orange County, Monterey, and Santa Cruz. They form enormous, beautiful clusters in groves of trees.

Some land in coastal forests in eucalyptus trees on ocean bluffs. Others are in areas near dunes, and boardwalks or camping grounds with magnificent sunsets.

This is the destination that is easiest to see. You can have the beach and the butterflies too!

The East Of The Rockys Migration

The August 1976 issue of National Geographic Magazine lays out the basic story. It was written by the Canadian scientist, Dr. Fred Urquhart, who began working on the monarch mystery in the early 1950s. In 1976 he finally found a butterfly in a Mexican mountain forest that was tagged in Chaska Michigan by one of his own volunteers. He found it because a huge branch holding thousands of butterflies broke and fell at his feet. What are the odds of that!

This destination is in Michoacan, part of the Sierra Madre mountains in western Mexico. This is a magnificent sight, Entire, huge, oyamel fir trees are covered in butterflies. It looks like a wonderful place and is now the Monarch Butterfly Biosphere Reserve. As a traveling gardener, I would love to see it.

It’s not a trip to the beach though. First, you fly to Mexico, drive several hours into the mountains, ride one of the villager’s horses up the mountain, then where the horse has sense enough to stop you hike the rest of the way, But then you get monarchs by the millions.!

For many years this place was a secret even to the monarch hunting Mexican scientists. There is a little village that welcomes the butterflies every year and sees in them, their departed ancestors as they celebrate the Day of the Dead, with fruit and prayer and butterflies. But they apparently weren’t talking!

Note that the solution to the monarch mystery came through both scientists in a wide variety of fields and volunteers also widely spread, in backyards and farm fields everywhere.

It is this fascinating confluence of a unique and charismatic insect and an innovative application of science. Then you add everyday people who plant $5.00 milkweed in pots and gardens everywhere that makes the whole thing work. It’s better than a Sherlock Holmes mystery!

Spring Migration-The Journey North

(See Green Lines On The Map Above)

In the mountains of western Mexico, now a national park, the butterflies begin to move. In February, they do a little warm-up in preparation for their marathon. They move about the mountains in great orange swaths, sweeping from one slope to another. In March, they move in earnest- tiny orange compasses with wings!

By capturing traveling monarchs, researchers have improved our knowledge of how they move and where they go. We are now aware that it takes as many as five generations of butterflies to make the trip north.

Generation One

This generation survives about another month, long enough to reach the Gulf states region. Here they lay the eggs of the next generation and die. Their work is done.

Generation Two

This group will reach a wide range of the southeastern US and produces the next generation.

Generation Three, Perhaps Four Or Five

North is the summer breeding range, within the US and Canada, this is the target of the third generation. They will lay the eggs of the fourth generation. Depending on forage, weather, wind, predators or whateve they face the trip may include from 3-5 generations born along the way.

Fall Migration-The Journey South

(Follow The Brown Lines On The Map Above)

The monarch, unlike many other butterflies, cannot overwinter. It cannot survive a cold winter in any stage of its life cycle. It migrates to survive. The journey south is the complete province of the super generation. They will make the entire journey to their southern home in one trip.

The Top Guns

Think of the generations of monarchs as coming in cycles. Winter through summer has 3-5 generations of short-lived butterflies, constantly reproducing. The super generation is very different. They have long but arduous lives. With a lifespan of about 8 months (very long for a butterfly), they are the adventure travelers.

Think of them as the Top Guns of the butterfly world! Each butterfly makes the whole journey. This is 50-100 miles per day. ( The record is 265 miles!) Rain, wind, heat, cold, predators, and no food in some places. It’s a dirty job, but somebody’s got to do it!

What’s The Trip Like?

This is a google earth Video that traces the northbound trip from The Mexican winter habitat, It is fairly long and gives you a sense of what the butterflies really do. It will show you, visually, what is happening to the monarch’s habitat.

It’s like the travel videos you watch to see if you really want to go to Ulan Bator!

Are You Intrigued?

Here are a few ways to get involved.

  • Are you near any of the likely routes? ( Do you see big black, white, and orange butterflies?) You can sign up online to enter your observations to Journey North records of the migration. Here is the link to the signup form.
  • If you live in Monarch territory (most of the US and a lot of Canada.) Plant some milkweed, plant some nectar-filled flowers.
  • Start a butterfly garden. Below are two articles that might help. Garden With A Bonus, butterfly gardens. Butterfly Garden In A Pot-for, the spacially challenged or the just plain lazy.
  • Join a butterfly count. (Yes, it’s like a bird count) These are done at set days in conservation areas or public botanical gardens or your local garden club.
  • Take a class. Butterfly gardening has become very popular. Call your county agricultural extension office. They may well be offering some classes or have university-based literature for you at no charge. I am a volunteer Master Gardener and I think you would be surprised at the resources you can find. Try also your best local garden centers, garden clubs, and your nearest Botanical Garden.


County Agricultural Extension Service- This is a place for science based information suited to where you garden. It is developed from the research of your own state Land Grant agricultural college. Here is how to find your if you don’t know it. (Very few counities in the US do not have a local office, If you don’t just use the closest one.

Florida Friendly Landscaping Guide To Plant Selection– If you live in Florida you can’t do better than this book which you can find online or in hard copy. If you don’t garden in Florida, look at it anyway. It will show you what a good plant selection list looks like!

What the Butterflies Want-this is mine, I hope it helps you.

Journey North

Monarch Watch

North American Butterfly Association-Plenty of good information online, and more.

Plant A Garden To Attract Butterflies- In A Pot-This is mine also, it should help if you want to start small, or plant on the patio.

Smithsonian Gardens-A quick outline, click through for more information

Xerces Society-This national organization is all about the pollinators and protecting the endangered ones.