Monarchs are magnificent orange-red butterflies that capture our imaginations and require our protection. Their caterpillars feed on Asclepias genus plants and a few others in the milkweed plant family. To survive, the Eastern U. S. and Canadian Monarch populations must make a migration journey of more than 1,000 miles each way, taking up to four generations to complete. Western population may not take 4 generations and non-temperate zone monarch populations worldwide do not require any migration.
To support the monarch’s life cycle and fall rearing, several species of milkweeds are maintained in the public gardens, greenhouses and non-public areas of the Virginia Living Museum, which has been a certified Monarch Waystation since 2005.
The Museum has reared the migrating generation of Monarch butterflies since 1988 and has tagged and released migrating adults since 1996.
You can follow the monarch migration on two web sites:
Watch a monarch emerge from its chrysalis:
Monarch Watch tags are about 1/4 inch round, made of weather proofed paper with a strong adhesive. Each has a code number and Monarch Watch address printed on them. Scientist and citizen taggers gently catch monarchs, place a tag on the lower part of a hind wing and release them unharmed. The tagger records the tag code, date and location tagged, then sends in the sheet to Monarch Watch. If the butterfly is later found and its tag reported, Monarch Watch can let taggers know when and where their butterflies were recovered. The butterflies can’t be tracked in “real time” yet.
Even with over 50 years of tagging data, monarch mysteries remain. How do the Monarchs find the overwintering sites each year when they are several generations descended from last winter’s overwintering insects? Exactly how does their homing system work, especially when they are blown off course? Their journey to Mexico is like a 6-foot-tall human circling the globe 11 times in a row!
For Peninsula monarchs, migration can begin in mid-September while some breeding continues, then peaks in late September or early October and most are gone by October 20th. Monarchs arrive in Mexico beginning early November and into December.
The Monarch migration is considered to be in “grave danger,” with populations decreasing by more than 80% over the past 20 years. Scientists attribute the continuing decline in migrating monarchs to deforestation in Mexico, extreme climate fluctuations in North America and the growth of herbicide-based agriculture destroying crucial milkweed flora in the Midwest.
Three butterflies tagged by the Museum have been located along the migration route. One butterfly was found in Mexico in February 2001 and another was recovered nearby in Newport News in fall 2001. The third was photographed in a butterfly garden in Austin, Texas on October 25, 2008. It was found by a six-year-old boy doing a science project on migration. The monarch (shown here) had traveled 1,306 miles in the 22 days since it had been released by the VLM.
Neat Monarch Migration Stats
- Monarch butterflies are 3 cm long, weigh less than 1 gram, and fly on paper-thin wings up to 4600 km to Mexico.
- The furthest journey recorded of a tagged monarch butterfly was about 2750 miles from Grand Manan Island, Bay of Fundy, New Brunswick, Canada to Mexico.
- Monarch migrants move 10 to 15 miles per hour for 6 to 8 hours per day, depending on wind speed, average 44 miles per day but can move up to 200 miles per day.
- Glider pilots have seen monarchs as high as 11,000 feet above the ground.
- Radar has picked up monarchs flying as high as 5000 feet off the ground.
- Monarchs can’t fly below temperatures of 57°F (unless they bask in the sun or shiver to warm their flight muscles).
- It’s been estimated from tagging studies that 25-50% of monarchs survive the fall migration.
- Migrants from northern sections of N.A. take 8-10 weeks to reach Mexican overwintering sites, while those from further south take 4 to 6 weeks. Migrants arrive at the sites in November and continue to the end of December.
How Can I Help Conserve Monarch Butterflies?
Plant milkweeds and butterfly nectar plants in your yard. This creates a nursery for the summer generations and a “fast food” stop for migrating monarchs. For more information on certifying your yard as a Monarch Waystation, go to www.monarchwatch.org/waystations. Plants suitable for a Monarch Waystation are sold at the Museum’s spring and fall plant sales (the last two weekends of April and September).
If you find a tagged live monarch, CONGRATULATIONS! Your options: catch it carefully or photograph the tag. If you catch it, write down all the tag information, the date and time you caught it, leave the tag on the butterfly and let it go. If you photograph it, get the same information from the photo. Contact Monarch Watch by the email or phone number on the tag and leave the tag letter/number code, your phone number and the information you gathered. You would gather and send the same information from the tag of a dead tagged monarch. If the person who tagged the butterfly turned in their data sheets then Monarch Watch will be able to give you information on where it came from. These “citizen science” data help piece together how a monarch makes its long journey to Mexico.
Links for Teachers
- The Magic of Monarch Butterfly Migration Teacher Guide from Journey North
- Core Teaching Resources from Journey North
- Symbolic Monarch Migration
- Monarch Watch in the Classroom Home Page
- Monarch Teacher Network
- U.S. Fish and Wildlife Service’s Monarch Information