You see them especially in late summer, the elegant monarch butterflies, with their large vari-colored orange and black wings fluttering by on their way 
south. They’re a fixture of the North American ecology, a common sight that's becoming less and less common, as it happens.
Researchers say that in recent years their numbers have been cut in half, due to habitat destruction both here on their summer ground and in Mexico where they overwinter.
Monarchs lay their eggs on milkweed plants, Only that species will do for this purpose. And the milkweed is in decline because of genetically-modified field crops. Farmers spray these field with herbicides that the crops are resistant to. Weeds, among them the milkweed plants that were once common in such fields, are wiped out.
On their winter ground, in central Mexico the trees on which they perch in great clusters are being cut down.
“It’s clear we’ve lost an awful lot of habitat, mostly over the last ten years,” says Orley Taylor, who heads “Monarch Watch,” based in Lawrence, Kans. “The population has declined significantly.”
His organization is trying to stop monarchs from disappearing completely. Taylor, a University of Kansas entomology professor, says we probably won’t ever see monarchs in their previous numbers, since they are fighting habitat destruction at both ends of their range.
Since the early 2000s, herbicide-resistant soybeans and corn have become widespread. A 1996 study that Monarch Watch contributed to had shown that about half of monarchs in the United States came out of corn belt in the Midwest. Milkweed had been hard to remove from corn fields, so it persisted in great numbers as ideal habitat for the butterflies.
“To lose (corn fields) as a habitat meant losing the base that sustains the population in the Midwest,” Taylor said. In Mexico and the United States the monarchs are losing habitat at the rate of about 6,000 acres a day, according to Monarch Watch.
There are several ways to reduce the threat. Monarch Watch encourages people to create monarch way stations or microhabitats with milkweed for monarch eggs and nectar plants for grown butterflies. The program has helped to start 5,000 such projects.
Monarch Watch encourages people to plant milkweed all over, including roadsides. Taylor has talked to the Kansas Department of Transportation about including milkweed in the mix that is planted on highway borders throughout the state. “We want to discourage the practice of making roadsides look like people’s front lawns.” Taylor said. “We need a new ethic in our approach to a lot more landscapes.”
Taylor and the other staff for Monarch Watch work year round on monarch conservation, but he says they need more help.
“This is a program with no end in sight,” Taylor said. “If we’re going to save this migration, we need a lot of partners.”
Jim Lovett, Monarch Watch staffer, estimates that the program sends out about 200,000 butterfly tags and 2,000 monarch-rearing kits to people across the country each year. The center sends about 100 monarch-rearing kits – including unhatched monarchs – a day in the fall because people want to raise them in time for the butterflies to make the migration.
When the program sent out news releases, asking for volunteers, Taylor said the response was extraordinary. “What we discovered is that the citizens of this country are very interested in natural phenomenon and want to contribute,” he said.
Monarch Watch’s Facebook page, launched about a year go, has nearly 6,000 followers from across the nation. They use the page to communicate their enthusiasm for conserving the species. People post pictures, trade tips and let others know when they’ve started spotting monarchs.
“As butterflies go they are large, easy species to work with, ”Taylor said, “They are exceptional and people are attracted to them.”
Visit the Monarch Watch Web site.