300 Million Butterflies Will Fly Through Texas This Spring

Monarch populations are in decline, but a surge is expected for the 2019 spring migration.

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Apr 3 2019, 8:17pm

Image: Shutterstock

An estimated 300 million monarch butterflies are expected to fly through Texas this spring, an increase of 144 percent from last year.

Monarch butterflies migrate southward in the autumn, from the central United States toward Florida and Mexico, and back up north in the spring. Over the last 20 years, populations of monarch butterflies across the North American continent have dropped by approximately 90 percent, according to the US Fish and Wildlife Service, largely due to urban development.

A 144 percent rise from the previous year’s migration is very promising, Craig Wilson, senior research associate in the Center for Mathematics and Science Education at Texas A&M, said.

“Figures show the highest number of hectares covered [by monarchs] since at least 2006,” Wilson told Texas A&M Today. Monarch numbers are usually estimated by how much ground they cover, in hectares.

Andrew Rhodes, Mexico's national commissioner for protected natural areas, announced in January that approximately 6.05 hectares (15 acres) of monarchs have been measured at their overwintering grounds in Mexico. Only 0.65 hectares (about 1.65 acres) of monarchs were measured in 2013-14, making for a record low.

Wilson estimates 50 million monarchs per hectare, resulting in a total population of about 300 million passing through Texas.

Texas has recently seen its biggest bloom of bluebonnets in a decade in and around Big Bend National Park, and the plant is known to attract monarchs during their migration. Additionally, the milkweed plant that monarchs rely on for food is currently in plentiful supply in central Texas, according to Wilson.

Conservationists and enthusiasts have already started taking action to ensure a successful migration across Texas—personnel around Easterwood Airport in College Station have agreed are delaying grass mowing around areas where milkweed grows, for example. Wilson also told Texas A&M Daily that over 500 students are involved in monarch community projects such as milkweed across local gardens and parks.

“Texas is a crucial place for them” Wilson said. “They have to pass through the state on their way north in the spring and lay eggs."

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