Catching, and Releasing, Monarchs as They Flutter Down to Mexico

Corey Kilgannon/The New York Times Tim Walsh holding a monarch butterfly in Riverside Park that he was tagging as part of a conservation project.

Tim Walsh, 67, saw the fluttering orange and black wings on Tuesday afternoon among the flowers near the Riverside Park tennis courts, around 96th Street on the West Side of Manhattan.

“This is the latest in the season I’ve ever seen one here,” said Mr. Walsh after deftly scooping the monarch butterfly into his net. “They’re usually not around after Columbus Day.”

He gently pulled the butterfly out, and from a small kit that he had stuffed in his backpack he peeled off a tag â€" an adhesive disk smaller than a dime bearing contact information in tiny lettering â€" and gently pressed it onto the butterfly’s right rear wing.

For years, in September and early October, Mr. Walsh, who lives near the park on West 93rd Street, has been prowling this area, which he calls a favorite stopover spot for monarch butterflies during their long migration every year between Canada and Mexico.

“My theory is that they float down along the Hudson River, and the conditions are ideal today: warm with a gentle wind out of the north,” he said.

“They come down when they smell the flowers here,” he said, pointing out the purple-flowered butterfly bushes as well as the milkweed - a main source of food for monarchs â€" near the courts.

Mr. Walsh has always stood in wonder of the monarchs’ annual multigenerational migration, fluttering on the air currents for thousands of miles, Canada to Mexico and back. He marvels at how they mysteriously seem to find the route, by the millions, to specific forest spots in the mountains of central Mexico, where they survive the winter by roosting together.

“It takes four generations to complete the round trip,” Mr. Walsh said. In Mexico, the butterflies are a major tourist attraction, even as their numbers have dwindled in recent years as a result of extreme weather and a decline in milkweed.

“I used to be an avid fisherman but I get a lot more pleasure out of this,” said Mr. Walsh, who six years ago, became a volunteer tagger for Monarch Watch, a program based at the University of Kansas that relies on butterfly lovers across the country to catch, tag and release monarchs in order to gather migratory information.

Mr. Walsh submits a detailed list of the butterflies he has tagged and hopes that the tags - each has an individual code and a Web site address and a phone number â€" will be found in Mexico.

“They spread the word in those regions that they’ll pay five bucks for each tag that’s turned in,” he said. “Five bucks, in that part of Mexico, goes a long way.”

Mr. Walsh, an avid painter and fluent Spanish-speaker who teaches language teachers, said, “Years ago, when I was teaching English in Guadalajara, I painted a mural of monarchs flying over the curvature of the earth with no borders.”

“It said, in Spanish, ‘Art, like the monarch butterfly, knows neither boundaries nor nationalities.’”

Mr. Walsh said he had a 1967 Volvo station wagon with 230,000 miles on it, “and my dream is to, one day, paint some butterflies on it and go on the road following the migration.”

As he held the butterfly on Tuesday - the 17th monarch he has tagged this season and the only one he has spotted in the past week - he said, “You hold it by its thorax, for its strength, and by the front of their wings with its wings closed.”

“Sometimes people get very hostile, and say ‘What are you doing to those little butterflies?’” he said. “I have to explain I’m not bothering them in any way.”

“This one was probably up in Tarrytown this morning,” he said, making sure the sticker was firmly affixed. Then he let the butterfly go, and it drifted up into the breeze and over the tennis courts.

“I love that - whenever you let them go, they always fly south,” he said.