The Amazing Mexican Butterfly Migration (Complete Guide)
Every year millions of monarch butterflies migrate from North America to Mexico to escape the cold winter up north. Of all my travels around the world visiting a Mexican butterfly sanctuary is an absolute highlight.
The butterflies gather in pine forests near Mexico City and it is an absolutely amazing sight. No videos or pictures will ever do it justice and it is something that you really have to see in person to appreciate.
The Monarch Butterfly Migration is truly one of nature’s wonders. The epic journey they make all the way from the United States and Canada to Mexico is hard to believe. So keep reading to find out all you need to know about the migration and how and when to see them.
Why Do Monarch Butterflies Migrate To Mexico?
Monarch butterflies migrate south because they cannot survive the brutally cold winters up north. By traveling to the mountains of Mexico they can stay warm enough to survive the winter before returning home.
The butterflies will gather in enormous numbers on tree branches which helps them keep warm. Sometimes there are so many butterflies on a branch that their combined weight can cause the branch to snap!
Even though they weigh under 1 gram each, up to 200,000 can gather on a single branch. So the total weight of the butterflies can reach around 200kg! This a great example of how small things can accumulate into something big (in life).
The Mysterious Monarch Mexican Butterfly Migration
Every year hundreds of millions of butterflies travel from Canada and Northern U.S.A. to spend winter in the mountains of Mexico. Some butterflies also migrate to the coast of California but in much lower numbers than the Mexican butterfly migration.
The journey is up to 4,000km or 2,500 miles long and takes the butterflies up to 2 months to complete. Wow! And it gets even more fascinating than that.
In order to make the journey Monarch butterflies are able to extend their lifespan. Usually, a Monarch butterfly only lives for 2-6 weeks. But at the end of summer, a generation of butterflies is born that lives for up to 9 months.
This special generation of butterflies is the one that makes the journey south and spends winter in the mountains of Mexico. Then at the end of winter, the butterflies mate and then begin the journey north for the summer.
The butterflies that make the journey north only have a lifespan of 2-6 weeks. So they stop along the way to reproduce. This ability to suddenly increase their lifespan is quite unique and a bit of a mystery to scientists.
What is also a mystery is how the butterflies find their way to Mexico. Because the butterflies that begin the journey south are the great-great-grandchildren of the butterflies who made the journey the year before. So this means that butterfly that migrates to Mexico has never been there before! 🤯
There are a few theories that scientists have to explain how they find their way to Mexico. Some think that they may navigate by using the sun while others think they may use the earth’s magnetic field.
When Do Monarch Butterflies Migrate To Mexico?
The butterflies that migrate to Mexico generally start to migrate in Autumn. Every year the exact time may vary because it depends on seasonal variations such as temperature and weather conditions.
However, the Monarch butterflies that are migrating from the farthest north usually start traveling south around August. Then by the end of October, all of the butterflies have already left their northern summer homes.
When Is The Best Time To See The Monarch Butterflies?
The butterflies begin arriving in Mexico around November and leave in March. The peak times to see the butterflies are in February and the end of January.
The reason that the end of January and February is the best time is that the temperature starts to increase. As the temperature increases the butterflies are more likely to take flight.
If you visit in November and December the butterflies will have started to arrive but may stay on tree branches to keep warm. Even in January and February, the butterflies are much more likely to be flying around on sunny days.
When we visited the sanctuaries as soon as clouds appeared most of the butterflies stood still. But as soon as the sun came out thousands were flying everywhere!
So if possible make sure that you visit the sanctuaries on a sunny day end of January or in February to get the best out of your experience.
Day Of The Dead And The Mexican Butterfly Migration
The monarch butterflies arrive in Mexico at the start of November which is also the date of Mexicos Day of the Dead celebrations.
The Day of the Dead is a holiday in which Mexicans show respect and remembrance to deceased friends and family members. The celebration is particularly important in the state of Michoacán, which is where the butterflies migrate to.
Due to the fact that the butterflies start arriving on the same date as the Day of the Dead many locals believe that the butterflies are the souls of their relatives returning to them. So in Michoacán butterflies are extra special for many people.
Even amongst prehispanic cultures in the region, people believed that the butterflies contained the souls of ancestors visiting from the afterlife. So the butterflies have been a special symbol for people in the region for hundreds of years.
Where Do Monarch Butterflies Migrate To In Mexico?
Another interesting fact about the monarch butterfly migration is that they only travel to a very specific area of Mexico. That area is the pine forests in mountains west of Mexico City. These forests are found in Michoacán and the state of Mexico.
The forests in this region are all at quite high altitudes and many of the butterfly colonies are above 2,500m. The forests here are just the right temperature to make sure that the butterflies do not get too cold. There are also freshwater supplies in the region so the butterflies can find water to drink.
Another crucial factor that makes these forests a good place to spend winter is that there are no predators of the butterflies. So they can rest on the trees without fear of attack.
The Monarch Butterfly Biosphere Reserve
Because the Monarch butterflies all migrate to a very specific area of Mexico they are very vulnerable to deforestation. Because of this, the Mexican government recognized the need to protect the Mexican butterflies’ migration areas.
So in the 1980s, they set up the Monarch Butterfly Biosphere Reserve. This reserve covers an area of over 56,000 hectares and is now a UNESCO world heritage site.
There are 14 colonies of butterflies that overwinter in Mexico and 8 of them are found within this reserve. It is also estimated that 70% of the butterflies that migrate to Mexico are found within the reserve.
The aim of the reserve is to protect the habitat of the butterflies by preventing illegal logging. This has been a struggle as locals and organized crime groups still cut down trees to make money.
Monarch Butterflies And Milkweed
Although a lot of efforts are being made to reduce deforestation in the biosphere reserve the biggest threat to the butterflies is outside of Mexico’s control.
On their way to and from Mexico monarch butterflies only eat a particular type of plant called milkweed. The butterflies eat this plant and lay their eggs on it on their journey back north.
But there has been a drastic reduction in milkweed because of the overuse of herbicides and the destruction of its habitat. Milkweed has been treated as a weed in America’s farmland. So farmers rip it out and spray it with herbicides which caused a drastic reduction in butterfly numbers.
But efforts have been made in recent years to plant more milkweed and hopefully increase butterfly numbers.
There is a Mexican milkweed also known as the Mexican butterfly weed. But this plant can also cause harm to the butterfly migration.
People often buy Mexican butterfly weed to put in their gardens and attract butterflies. There was actually an increase in demand for the plant because people were concerned about the decrease in monarch butterfly numbers.
But the problem with Mexican butterfly weed is that it does not go dormant in the winter. This causes butterflies to stay close to the plants and not complete the migration to Mexico.
So the monarch butterflies in Mexico face a number of threats but it is good to see that efforts are being made to ensure their survival.
How To See The Monarch Butterflies In Mexico
In order to see the butterflies you will have to visit a sanctuary. All of the Mexican Monarch butterfly sanctuaries are within the Monarch Butterfly Reserve.
There are five colonies that are open to the public to see. Two are located in Michoacán and they are the Sierra Chincua and El Rosario Sanctuaries. These are the most popular sanctuaries in Mexico and also the ones we visited.
Then there are three other sanctuaries in the State of Mexico which are La Mesa, Piedra Herrada, and El Capulin.
The Mexican butterfly sanctuaries are all within a 2-3 hour drive of Mexico City. So you can visit any of them on a day trip from Mexico City.
But we recommend traveling to a town nearby and staying a night or two to get the best experience. That way you can also help the local economy which hopefully will discourage people from illegal logging.
Where To Stay While Visiting The Mexican Butterfly Sanctuaries
We stayed for 3 nights in Angangueo to visit the Sierra Chincua and El Rosario Sanctuaries. In both these reserves, there are millions of butterflies and it is worth visiting both as they give you a different experience.
Angangueo is also a peaceful little town in the mountains of Michoacán that is great to stay for a couple of days and relax. You can read all you need to know about Angangueo here.
If you would like to visit the Piedra Herrada Sanctuary then the closest town is Valle de Bravo. Valle de Bravo is another beautiful Pueblo Magico and is definitely worth staying for a few days.
Is It Safe To Travel To See The Monarch Butterflies In Mexico?
Some people may have questions about safety because the butterfly sanctuaries are located in Michoacán and the State of Mexico.
Both of these states do have problems with crime in certain areas. But if you are staying in tourist towns such as Angangueo or Valle de Bravo you will be safe.
But you of course should follow usual common sense and not wander around at night. Also while traveling through Michoacán you should avoid traveling at night in many areas.
We have been to all the places mentioned and never had any issues. The opposite happened, we met the most amazingly friendly people in those areas. You can read about how we made a new friend and our local experience in Angangueo here.
Now You Know All About The Mexican Butterfly Migration
Without exaggeration, it is one of the coolest things I have ever seen. No video or picture will ever do it justice. It is so magical seeing thousands of butterflies fly over your head and witnessing a part of their mysterious journey.
If you are living in Mexico City or are in the region during January or February you have to go see it. Out of all of the amazing things we have seen in Mexico it is right at the top of the list!
If you found this guide helpful or have any more information about the migration that you think I should add, please leave me a comment below.