Why San Antonio and South Texas are critical to survival of monarch butterfly population

South Texas is critical breeding ground for monarch butterflies

SAN ANTONIO – The monarch butterflies have a special meaning in Mexico and parts of the United States, including South Texas.

The butterflies are not just beautiful to look at, as millions of monarchs begin to appear in Mexico around Day of the Dead, they are believed to hold the spirits of lost loved ones.

They migrate to Mexico in the fall, passing through South Texas, but their population is slowly dwindling.

A study published in March showed a 53% decrease in areas in Mexico occupied by monarch butterflies last winter.

In the 2019-2020 wintering season, the area of forest occupied by monarch butterflies was determined to be 7 acres, down from 15 acres the season before.

RELATED: Monarch butterfly migration is unique and amazing phenomenon with Dia de Muertos symbolism

According to the study, lower-than-normal temperatures in South Texas when monarchs arrived in March and April of 2019 led to a slow growth of eggs and larvae during the Spring. This resulted in fewer monarchs to produce the following generations, including the one that migrates from Canada through the US to Mexico.

“We’ve been seeing more butterflies this year (2020) definitely because the weather was finally better in Texas,” said Ellen Sharp, co-owner of J.M.'s Butterfly B&B in Cerro Pelon, Mexico. “Whatever happens in Texas is super important for the Eastern monarch migration. The drought’s ended and there are more wildflowers. The population really kind of rebounded.”

Monarch butterfly migration is unique and amazing phenomenon with Dia de Muertos symbolism

Monarchs make one of the most unique migrations in the animal kingdom. They are the only butterfly known to make a two-way migration as birds do, according to the U.S. Dept. of Agriculture. But conservation groups fear their migration and the population is in danger.

The use of pesticides, deforestation, loss of habitat and more droughts caused by climate change are believed be the primary reasons for their population decline.

Texas plays a critical part in their conservation. According to the Parks and Wildlife Dept., Texas is situated between the principal breeding grounds in the north and the overwintering areas in Mexico.

San Antonio is currently seeing the fall migration take place. By the third week of October, most have passed through into Mexico. Conservation groups say an easy way to help the monarch population survive is to plant milkweed.

“Plant milkweed, preferably native. Whatever is native to your area and provide nectar plants,” said Darlene Burgess, Monarch Watch conservation specialist. “They build their nectar as a caterpillar and as an adult coming through all the way south through Texas. Nectar plants is just as important as milkweed.”

(Day of the Dead Monarch Butterflies)

The TPWD has also launched a new license plate campaign to raise money to help conserve monarch butterflies and other non-game, at-risk species native to Texas.

The public can vote in an online survey for their favorite design for the new monarch butterfly conservation license plate.

“The monarch butterfly is a species that is beautiful and iconic in that it is one of nature’s great migration stories,” said John Davis, TPWD’s Wildlife Diversity Program Director. “This great migratory story is in jeopardy with the overwintering population experiencing precipitous declines in the last decade. By adding the monarch to our family of plates, we hope to increase support for this beautiful migration event.”

In San Antonio, the annual Monarch Butterfly and Pollinator Festival is tagging and releasing monarchs in honor of those lost. Click here to learn more about their initiative.

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About the Authors:

RJ Marquez is co-host of KSAT News Now and reports for Good Morning San Antonio. He's been at KSAT since 2010 and covered a variety of stories and events across the San Antonio area. He also covers the Spurs for on-air and digital platforms, including his Spurs newsletter. RJ has reported stories for KSAT Explains.

Misael started at KSAT-TV as a photojournalist in 1987.