Monarch migration across Texas smallest in 14 years


Associated Press

AUSTIN- The annual migration of monarch butterflies that crosses Texas en route to Central Mexico is the smallest in 14 years, experts say.

Hundreds of millions of the large, colorful butterflies migrate to near Mexico City from the United States and Canada each fall. But herbicides, changing farming practices and weather are apparent culprits in reducing the numbers.

“We’ve had very few reports outside that narrow band,” Texas Parks and Wildlife Department biologist Mike Quinn told the Austin American-Statesman. “The biggest single report was 5,000 in San Angelo. All along Interstate 35 from Dallas, we’ve primarily had reports of single ones.”

The migration funnels through a 300-mile-wide corridor from Oklahoma City to Del Rio before crossing the border.

The leading wave of migrating monarchs has fluttered into Mexico by now, dependent on northerly winds to help them soar as far as 80 miles a day, close to the ground or thousands of feet in the air, Quinn said.

He said that, in addition to a hard freeze last February that killed many monarchs in Mexico, the insects have been harmed by biotechnology. They depend on nectar from wild milkweed plants, which are being killed by herbicides that farmers can apply more abundantly thanks to herbicide-resistant varieties of crops such as soybeans.

Chip Taylor, an entomologist and director of the Monarch Watch  program at the University of Kansas who has followed the migrations for 16 years, said that the butterflies — weighing less than half as much as a dime — are not strong fliers despite their 3- to 5-inch wingspan.

Last summer’s weather, which was colder and wetter than usual up north, may have delayed monarchs’ reproduction cycle so more winged travelers could be seen for several weeks, he said on the group’s Web site,

Monarchs are not an endangered or threatened species, despite their diminished numbers this year. Each female lays up to 400 eggs.

“They have been introduced around the world,” said Quinn. “The migratory phenomenon is potentially endangered, but I don’t know how you could separate the phenomenon from the species.”

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