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By Jill Austin
As the chill hits the northern United States and Canada every fall, monarch butterflies begin a migration south that launches a remarkable lifecycle.
“They are the Methuselahs of their species,” says wildlife biologist David Cook, comparing the 969-year-old Bible patriarch to this butterfly's lifespan that is up to eight times the length of fellow monarchs emerging at other times of the year.
The Monarch Relay
- A monarch flies south with the first cold snap, resting along the way, until it finds a sheltered, warm place to spend the winter.
- In spring, it migrates northward, stopping to drink from the emerging flowers, mate, lay eggs and then die, having lived for a total of 7-8 months.
- The new monarchs that emerge from these eggs fly north as well, but only travel a relatively few miles.
- They mate, lay eggs and die, having lived for about one month.
- Their eggs emerge and repeat the one-month lifespan. Up to five generational waves continue north until the weather signals the return.
“The whole phenomenon is amazing. This last generation finds their way to Mexico and they’ve never been there before. They end up in the same spot,” says Cook, a Tallahassee biologist with the Florida Fish and Wildlife Conservation Commission.
Protected Areas Provide Safe Passage
Millions of monarchs east of the Rocky Mountains overwinter at a specific forest in central Mexico—encompassing just 70 square miles— every year and to get there, they use Florida’s river corridors and coastal barrier islands.
On the Conservancy’s Cumberland Island Preserve in Georgia, groundsel bushes scattered among the dunes drip with migrating monarchs when the wind is out of the northwest, says Conservancy ecologist Malcolm Hodges.
The Nature Conservancy in Florida has helped protect almost 40,000 acres in this Panhandle pathway, including its Phipps Preserve and two additions to St. Marks National Wildlife Refuge where monarch tagging has taken place since 1988.
Counting Butterflies
Small stickers are gently applied to the wings of monarchs captured in the cool pre-dawn by volunteers headed by Cook.
“The secret is to find the trees and shrubs that are their overnight roosts. We shine the flashlights to count them as they are closed up and sleeping and then capture them with nets,” Cook explains. “We go on Saturdays so the public can join in, but days associated with cold fronts we go out too.”
On a total of nine mornings last fall, Cook and his volunteers counted 2,865 monarchs in St. Marks and tagged 2,584. They hear back about only a handful of their tags each year.
“We get a few reports of the butterflies ending up in Mexico, but we don’t get a lot of feedback,” Cook says. “This year we are using blue tags so it will be easier for people to spot and report a monarch tagged at St. Marks. I’d love to get more information from other groups tagging in Florida. I bought more tags for this fall if people want to help.”
For more information about the monarch’s migration or to volunteer, contact Cook at david.cook@myfwc.com.
Jill Austin is a senior conservation writer with The Nature Conservancy in Florida.
Nature picture credits (top to bottom, left to right): Photo © Ingo Arndt/naturepl.com
(monarchs); Photo © James F. Flynn Jr. (monarch on flower).
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