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Monarch butterflies
 Page updated on 03.10.2015
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Michoacán State is famous for the Monarch Butterflies. They migrate from the North every year and stay from October to March to protect themselves from winter and to breed. The state is also famous for its craft.

monarch butterfly Located in the State of Michoacán, 115km (72 miles) from Morelia, the Mariposa Monarca Biosphere Reserve occupies 152,461 acres close to the province of Mil Cumbres and is comprised of a group of mountains and hills. The highest points culminate around 3,600 m (11,800 ft) of altitude. The soils are made of light volcanic ashes whose water retention capacity is very high. In the lowest part, at 1,500m (4,920 ft) of altitude, some conifers start to grow and they are more and more as you go up. From 2,400m (7,870 ft), there are oyamel firs (Abies religiosa), cedars (Cedrella odorata) and cypresses (Cupressus sp). Higher, at 2,900m (9,515 ft) of altitude, the cedars disappear to allow room for ranges of oaks (Quercus sp), oyamel firs and pines (Pinus sp), and above 3,600m (11,800 ft), the oyamel firs are the dominant vegetation with a few bushes, mushrooms and epiphyte plants. The conifer species “Abies religiosa” holds a very high humidity level and is able to resist low temperatures, which is the preferred habitation for the Monarch butterflies. This phenomenon of migration of the Monarch butterflies intrigued the entomologists and biologists :

Why thousands and thousands of orange and black Monarch butterflies migrate from Canada and North of the United States (Rocky Mountains) to Mexico and back ?
When the nights become longer and the temperatures colder, this famous migrant butterfly flies thousands miles from Canada to Mexico. There, it spends the winter before going back, during the spring, to the northern countries to lay their eggs. The cities of Angangueo, Ocampo and Zitacuaro house the most important sanctuaries. The migration is estimated to 20 million butterflies per season !

     Above picture : monarch butterfly

July 2008 : The Monarch Butterfly Biosphere Reserve is a new Mexican natural site inscribed on the UNESCO World Heritage List.

Extract of the UNESCO site : "The 56,259 ha biosphere lies within rugged forested mountains about 100 km northwest of Mexico City. Every autumn, millions, perhaps a billion, butterflies from wide areas of North America return to the site and cluster on small areas of the forest reserve, colouring its trees orange and literally bending their branches under their collective weight. In the spring, these butterflies begin an 8 month migration that takes them all the way to Eastern Canada and back, during which time four successive generations are born and die. How they find their way back to their overwintering site remains a mystery".

monarch butterfly The Monarch Butterflies were born around the Great lakes, in the farming regions of the Canadian South-East and the north-East of the United States, in the corn and soy fields. Here, grows a perennial plant called Asclepias. It is a plant with clusters of yellow flowers and reddish peduncles linked to a stem filled with latex, a toxic substance stored by the butterflies in order to protect themselves from the predators.
Because it is an Asclepias, this plant is also called milkweeds and it has been used for thousands of years in the countries as a poison against the rodents and in herbalist’s shop as antiseptic and to cure constipation. It is also known to relieve rheumatism and tooth pains or provoke vomiting. The Monarch Butterflies lay their eggs on only 27 over the 108 species of Asclepias studied in North America. These species are able to bring the defenses and energy needed to make their annual migration.

     Right picture : monarch butterfly

The confirmation of this migration was confirmed only in 1975. The Odyssey lasts one month. They fly several kilometers a day, up to 130 km (80 miles) when the winds are favorable, before reaching one of the thirty overwintering zones located in central Mexico. They use the atmospheric currents that allow them to plan for 3,900 km to 4,500km (2,400 to 2,800 miles).

When the sun warms the winter, thousands of butterflies cover the trunks and branches, creating a mobile sky and ground made of tiger aisles, breaking the profound silence of the forest.
The scientists explain that the Danaus plexippus (scientific name) leave grease on the bark of the trees and on the ground to attract the next generations of butterflies. The Monarch Butterfly migrates only once to Mexico. According to the studies, it lives about 9 months while other butterflies live only a few weeks, or even a few days. The scientists haven’t figured out yet the mystery of orientation to go from one point to the other !
In the spring, the butterflies naturally make their migration to the Canada and go back to Mexico in the fall.

The Purépecha Indians interpreted the arrival of the butterflies as a visit from their deceased because it happened just before the ceremonies celebrated to venerate the ancestors, ritual linked to the Christian celebrations during the reign of the Spanish viceroyalty. The Mazahuas and the Otomís called this insect the Cosechadora (combine harvester), referring to the cycles of farming production.

A lot of butterflies died because of the natural elements like cold and snow falls as well as the deforestation and the spreading of pesticides. The government of President V. Fox (2000-2006) became aware of the importance of the protection of theses butterflies and decided to establish more reserves. The preservation of the sanctuaries is also one of the priorities of the actual government of Calderón (2006-2012). The conservation of this Biosphere Reserve is the result of intense efforts conjugated from the local and federal governments, the States, the WWF-Mexico, national and international organisms financed by private companies and community organizations of the region. As part of the reconversion of productive activities, huge efforts have been made during the last past years to encourage the biggest number of families, especially from an indigenous origin, really understanding the durable development (their economy was based, still recently, on the mining industry and the forestry plantation). It is only if they are educated and aware of the many opportunities offered by a protected place such as this one that they will be able to harmonize their efforts with the actions of conservation.

Read a beautiful and very complete article "Hinterland Who’s Who” about the Monarch Butterfly : . Canadian website in English/French.

There is also an interesting article from "Parks Canada” : (article in english/french).

Consult also the Website of Kansas University :

You could see then flying in huge clusters and always reaching the same isolated parts of Michoacán. They take flight in September/October for breeding during the dry season. When they reach the neo-volcanic axis, they establish themselves in hibernation colonies, using branches from the oyamel (Mexican conifer tree) in the Southwestern sides of the forests, where they stay for 5 months from when they arrive in October until they leave the end of March. After a mating period of one month, the butterflies that survived the wintering go back from where they came.

Visita al Santuario de Mariposas Monarca "El Rosario" en Michoacán, Mexico. Visit of the sanctuary of monarch butterflies in the state of Michoacán  

Take a tour from Morelia to get there more easily and to get good information about this mysterious migration (entrance fee: $25 plus tips for the guides; open 10 AM-5 PM, daily from mid-November to March). Allow a full day.


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