The monarch butterflies you see in the fall are long distance travelers, biologically and behaviorally adapted to make the long flight to the same mountain forest in Mexico where their ancestors spent the winter.
Monarchs are the only butterfly known to migrate long distance and roundtrip. It takes four generations to complete the journey and this fourth generation will live the longest and travel the whole distance to Mexico. They will neither mate nor lay eggs until their spring return, conserving their strength for the more than 2,000 mile flight. The monarchs innate ability to integrate the time of day and the sun's location in the sky is a modern navigation marvel. Their large complex eyes monitor the sun's position in the sky and their internal clock is centered in the antennae. Eyes and antennae send information to the brain. Scientists and engineers at Michigan and Massachusetts universities believe they are close to cracking how this information is processed by monarchs travelling to the same destination year after year.
Monarchs will stop to nectar for fuel along the way to last through winter. They will ride air currents to conserve energy. In the spring, they begin the journey back north through successive generations. This return trip requires milkweed plants. These are the only plants where monarchs will lay their eggs and hatching caterpillars will feed. Their children’s grandchildren, the fourth generation, will make the return trip the following fall.
How to Help Monarchs
The monarch migration is a natural wonder, yet their numbers are in serious decline from weather events, habitat loss and other factors. You can help by planting native milkweed plants and other nectar sources in backyards or back forties, at schools, businesses, parks, roadsides and other open places.
- A truly effective monarch habitat will be at least 100 square feet.
- Monarch plants need lots of sun; therefore, monarch habitats need to be located in an area that receives at least six hours of sun a day.
- Native milkweeds and nectar plants will do best in relatively light (low-clay) soils.
- It's best to have at least 10 plants with two or more species that flower at different times of the season.
- Good drainage is needed to avoid root rot and provide good aeration of the roots. Areas with poor drainage may need more tolerant species such a swamp milkweed and New England aster.
- To assure that the maximum number of monarchs survive in your habitat, the plants should be relatively close together. However, they should not be crowded.
More tips for Monarch Habitats
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