Monarch butterflies
About Monarch butterflies
Each year millions of Monarch butterflies spend the winter clustered in the humid pine-oak forests of the Sierra Madre Mountains on the border of Michoacán and Mexico State. They have flown from as far aways as southern Canada, as much as 3000 miles, to reach their winter habitat, where they will form huge clusters that hang like ornaments from the trees.
Once the days lengthen and the air warms in early spring, they mate, and the females begin their long migration north. During their journey they are supported by nectar from flowering plants. Breezes and thermal winds help them on their flight.
As soon as they reach Texas, the females begin laying their eggs. This first generation to be born fans out across the southern U.S. laying eggs along the way. The second generation born, fly even further north, laying eggs along their way. The third generation to be born can reach as far as southern Canada. By this time, the Monarchs are present throughout the territory east of the Rockie Mountains. In the fall, the fourth generation of Monarchs returns to México, flying in large groups until they reach their winter habitat and the cycle begins again.
Monarch butterfly migration
The annual migration cycle of the Monarch butterfly has been described as the most spectacular in the insect world, and although factors that affect this incredible journey are still being discovered, many consider it a “threatened natural phenomenon” attributed to human interference, whether it be habitat loss, pesticides and insecticides; captive-rearing; mis-informed planting of tropical milkweed; the spread of parastites affecting the health of the Monarchs, or all of the above.
“Butterflies… flowers that fly and all but sing.”
– Robert Frost
Migration Map
Help Monarchs During their migratory journey
“Waystations” are places that provide nectar and shelter for Monarch butterflies as they migrate between their northern and southern habitats.
To create a waystation you need a sunny site, plants providing year-around blooms, close spacing between plants to create shelter and refrain from pesticide use (see our page on Nature-friendly Pest Control).
Check our list of plants for nectar-producing plants for butterflies.
Franke’s Vivero can provide you with most, if not all, the plants you need.
Create a Puddle for butterflies
Perhaps you’ve seen butterflies gathered around a damp spot on a dirt path or beside a stream? Those butterflies aren’t thirsty. They are puddling. Butterflies “puddle” when they are in search of minerals, especially salt. Sometimes they puddle when nectar food sources are not plentiful.
Place sand and a few flat rocks in a shallow dish, set in a sunny area of your garden and keep moist with water. Overripe fruit can also be placed in the puddle to offer another source of nectar. They are particularly fond of sliced rotting oranges, grapefruit, strawberries, peaches, nectarines, apples and bananas (you don’t have to have a puddle to set out fruits, just make sure it’s really ripe so it is at its ultimate sweetness.)
Tropical milkweed (Asclepias curassavica)
important information About tropical Milkweed
OE – a Harmful Parasite
After years of maintaining a small plot of tropical milkweed (Asclepias curassavica) at our pollinator garden at Parque Juarez, to support our local population of Monarch butterflies, we have recently learned that this practice is enhancing the spread of a parasite Ophryocystis elektroscirrha, or OE, which “weakens the infected butterflies (if they live to their adult stage), reduces their lifespan, and it is now spreading into the rest of the N. American population, and hindering the famous migration to Mexico.” Source Article
– Monarchs have a growing disease problem. This disease is wiping out tens of millions of migrating monarchs, leading to smaller than normal winter colonies.
– We know this increase is not being driven by any natural environmental factor, which argues the cause is humans.
– The timing of the increase coincides with the rise in collective efforts to save the monarchs in the last 15-20 years, including mass-rearing of monarchs and planting of tropical milkweed.
Tropical Milkweed in Mexico Threatens the Migration
People have reported clusters of migrating Monarchs in San Miguel. These butterflies can be lured off their migratory journey by the presence of Tropical Milkweed, which can cause them to become part of our local sedentary population, threatening the crucial migration cycle and the welfare of U.S. and Canadian Monarch populations.
We are in the process of identifying milkweed that is native to Guanajuato that will support our local population, but in the meantime we encourage you to cut back this milkweed species during the migratory season. October 15-Decemember 1 and February 15 – March 10.* The milkweed will regenerate quickly after being cut back, so make sure there are no blossoms during this time.
You can calculate the time to cut back more accurately by visiting the Journey North’s live maps: https://maps.journeynorth.org/
Planting milkweed in the U.S. and Canada
If you want to help the Monarchs by planting milkweed in your garden, it’s critical that you plant the variety that is native to your location. This is a good article that spells out at least part of the problem with planting non-native milkweed in the United States. Science
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