The Biggest Spring Migration Of Monarch Butterflies In Years Is Passing Through Austin

Mar 20, 2019

The annual return of the monarch butterfly is underway. They started showing up in Austin about a week ago, according to the crowdsourced online tracker at Journey North.

And, if you catch a glimpse of their orange and black wings over the next few months, you could be witnessing part of the biggest migration of monarchs in recent memory. 

Things have been going uncharacteristically well over the last year for the butterflies, which pass through the central part of the continent every year.

In 2018, they enjoyed good weather in the Midwest, where many monarchs lay their eggs on milkweed plants during the summer. 

“[The number] is going to represent as many monarchs as we can produce with the current amount of milkweed and the absence of weather disasters,” Tierra Curry, a scientist with the Center for Biological Diversity, told KUT at the time.

The creatures appeared to fare well during their fall migration to Mexico, too. Once back in Mexico the insects covered 15 acres of land – up from a low point of under 2 acres during the 2013-14 winter season. That could mean the number of monarchs could be up as much as 144 percent, according to a Texas A&M University report.

But that doesn't mean things still couldn't go wrong. 

Too Early for Milkweed

"This is an unusual spring," says Chip Taylor, the director of Monarch Watch at Kansas University. "You’re seeing an unusual number of monarchs in Texas for this time of year. What I would like to see is the monarchs really confined to Texas and Southern Oklahoma for the next four weeks."

The reason, Taylor says, is that the butterflies arrived in Texas "a little too early" for the milkweed to come up.

To ensure the biggest number of butterflies return north, he says, they should stay and lay their eggs on milkweed in Texas and Southern Oklahoma for the next few weeks.

"The butterflies develop a little bit faster down in Texas and Oklahoma," says Taylor. "So we want to see them stay put ... then send the first generation north in May and early June. When we see good numbers coming out of Texas in May and early June that usually means the population is going to go up."

Long Term Threats

Even that wouldn't assure a bright long-term future for monarchs. While the population that winters in Mexico saw an increase last year, another population that migrates to California almost vanished.

One good year for the Midwestern migratory monarchs also doesn't mean the factors that contributed to their decline — like habitat destruction — have improved. 

"We have to face the facts that climate is changing," says Taylor. "This whole migration is in jeopardy given the loss of milkweed and the fact that climate is changing in an unfavorable way to sustain this population."

Taylor expects a final big wave of monarchs to enter Texas from Mexico by the end of the week. So, if you want to help the butterflies, the time to plant milkweed is now. That will allow them to reproduce as they move north.

In the fall, Texans are encouraged to remove non-native milkweed and provide the insects with other nectar flowers to encourage their southern journey.

If you think you see a monarch, you can report it online at sites like Journey North.