Wall Street Journal:
The sighting didn’t occur in some flower-filled field but in Queens, perhaps better known for shopping malls than wildlife. When I heard that an employee of New York City’s Department of Environmental Protection had discovered three chrysalises in a planting bed near 97th Street and 63rd Road, I boarded the M train to join the festivities.
“They were munching on Asclepias incarnata,” otherwise known as milkweed, the species’ favorite food, said Maria Corporan, the supervisor gardener who discovered them earlier this month. “I always look at the plants to see if there’s any diseases. I was like, oh my God, I guess we’ve got monarchs here.”
She wasn’t referring to fully formed butterflies but the humble caterpillars that precede them. The caterpillars create chrysalises, or pupas, the cases that protect and envelope them as they transform.
Ms. Corporan showed me a picture on her phone. To my surprise, the caterpillars were rather attention-grabbing on their own—large and with a monarch’s characteristic orange, black and white pattern.
She pointed out two of their chrysalises in the planting bed. I was surprised she found them, even though she saw the caterpillars at work. The chrysalises hung like jade-colored dewdrops, hidden on the underside of a dogwood shrub’s leaves.
Ms. Corporan feared that the third one, hooked onto a sweet pepperbush, was too close to the bed’s guardrail and could get knocked loose by a passerby. She took it back to her office, hoping it would emerge there.
I assumed that the butterflies would require a habitat at least the size of a vest-pocket park, but the planting bed appeared to be no more than 20 feet long and less than 10 feet wide. And butterfly habitat wasn’t even its primary purpose.
It was a bioswale, a piece of land designed to filter silt and pollution from surface water that might otherwise overwhelm water-treatment plants during heavy storms. “We’ve built over 2,500 around the city,” with thousands more planned, said Vincent Sapienza, the Department of Environmental Protection’s acting commissioner.