Our Wonderful and Mysterious Migratory Monarchs – The Link News


The State We Are In By Jay Watson, Co-Executive Director, New Jersey Conservation Foundation – To the casual observer, the flight of monarch butterflies can seem as random as a breath of wind. In backyards and gardens, they flit from flower to flower until the wind lifts them again in a new direction.

But these beautiful insects, with their stunning orange and black wing patterns, never fly aimlessly. They are in fact among nature’s most useful flyers.

Each year, the generation of monarchs that emerges in late summer and early fall undertake one of the most amazing migrations in the animal world, traveling up to 3,000 miles from the north to the southeastern Canada to the montane forests of central Mexico. It’s a perilous journey, and all the more incredible when you know that each butterfly weighs less than a paper clip!

The long migration is just one of the many challenges monarchs face.

In July, the International Union for Conservation of Nature (IUCN) placed the monarch butterfly on its Red List of Threatened Species as “endangered”, saying habitat destruction and climate change are bringing the monarch butterfly closer together. species from extinction.

According to the IUCN, the population of migratory monarchs in North America has declined significantly over the past few decades. Forest habitat has been cleared to make way for agriculture and urban development, while pesticides kill both insects and milkweed, the host plant that monarch caterpillars feed on. Extreme temperatures, severe weather and wildfires add to the threat.

The western monarch population winters on California’s northern coast and is most at risk of extinction, having declined by an estimated 99.9% – from 10 million to less than 2,000 butterflies since the 1980s. The eastern monarch population winters in the mountains of Mexico and is much larger, but the IUCN says it declined by 84% between 1996 and 2014.

Efforts to save monarch butterflies — from planting milkweed to research to habitat protection — are underway in New Jersey and beyond, but the biggest problem is the widespread and growing use of pesticides and herbicides over vast portions of our country’s landscape. Chemical residues cause enormous losses to hundreds of pollinator species.

New Jersey plays a special role in the fall migration of monarch butterflies along the Atlantic coast, as thousands of butterflies are brought to the tip of the Cape May peninsula (as are migrating birds). There they rest and refuel while waiting for favorable weather conditions to cross the Delaware Bay.

The monarch’s annual migration provides excellent opportunities for researchers and the public to learn more about life cycles, population trends and migration patterns – and to find ways to help the butterflies bounce back.

Since 1990, the New Jersey Audubon Society’s Cape May Bird Observatory has hosted the Monarch Monitoring Project (MMP), a research and education initiative.

Throughout September and October, MMP observers conduct a monarch census, counting butterflies along a five-mile route through various coastal habitats. The annual census allows scientists to track long-term changes in monarch numbers.

MMP researchers also tag monarchs with tiny adhesive stickers that allow observers along the migration route to track their progress. Each sticker is printed with a unique alphanumeric code that indicates where and when the individual butterfly was tagged. The stickers are light and positioned on the underside of the wing so as not to interfere with the flight.

According to Monarch Watch, the national organization that oversees the tagging database, the generation of monarchs that metamorphose and emerge from their pupae in late summer and early fall are biologically and behaviorally different from those which emerge earlier in spring and summer.

While late spring and summer monarchs are genetically programmed to reproduce rapidly and lay eggs on milkweed plants, the generation that emerges in late summer and early fall does not reproduce. Instead, this group’s only instinct is to make the ultra-marathon trip south.

This genetic event and similar timed ecological events are simply breathtaking! During a nature walk in late August with New Jersey Conservation Foundation staff biologist Dr. Emile DeVito, he pointed to a tiny white monarch egg on the underside of a milkweed leaf and noted, ” This egg is programmed to fly to Mexico.

Migratory butterflies feed on the nectar of a variety of flowers as they move south. Despite the long journey, they must build up enough fat reserves during their two-month migration to feed through the winter. Once in Mexico, the butterflies will roost with hundreds of thousands of others.

Scientists believe some monarchs even find their way to the same tree their ancestors landed on in previous years. How do they know where to go? It is an enduring mystery.

In the spring, this generation will finally reproduce, but will not live long enough to make the full trip north. Rather, it will be their children, grandchildren and great-grandchildren who will live next summer.

What can you do to help monarch butterflies? You can plant milkweed in your flower garden without chemicals; Swamp milkweed and common milkweed are the best and easiest to grow, and both are native to New Jersey. Milkweed seeds are available at native plant nurseries, and many schools, businesses, and nonprofits sponsor planting programs.

If you manage a meadow, try to get surrounding landowners to reduce their reliance on pesticides. Monarchs need thousands of stopover sites that are free of pesticide and herbicide residues. Advocate with government officials to completely ban the use of neonicotinamides nationwide.

If you are spending time in or near Cape May, consider volunteering to help with butterfly counting and tagging. You can also “adopt a monarch” by donating to the MMP program.

Anyone interested in learning more about monarch tagging is invited to attend free MMP demonstrations in Cape May most days in September and October. A Monarch Festival at the Cape May Nature Center is scheduled for Saturday, September 25. For more information, visit https://njaudubon.org/monarch-monitoring/.

And to learn more about preserving New Jersey’s lands and natural resources, visit the New Jersey Conservation Foundation’s website at www.njconservation.org or contact me at [email protected]


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