A breeding effort aimed at increasing the population of the Baltimore checkerspot butterfly - the official state insect - has suffered a setback, in part because of some unruly Montgomery County geese.
Dozens of checkerspot caterpillars that successfully wintered at a Montgomery County farm escaped into the wild when pet geese apparently poked holes in the cages that confined the insects to the turtlehead plants on which they breed.
Meanwhile, 23 caterpillars that had been growing in a tent at the Maryland Zoo in Baltimore under the supervision of volunteers are down to just 14 insects.
"We're down to such a low number, we've got to start over," said Pat Durkin, co-founder of the Washington Area Butterfly Club and coordinator of the Baltimore Checkerspot Butterfly Restoration Project of Maryland.
This week, Durkin took the last insects from the zoo tent to her Washington home to help them breed in captivity as she made plans for another foray to capture wild adult butterflies. Later this summer, she'll return the eggs they lay to the zoo.
The checkerspot sports the red, black, white and orange colors of Maryland's founder Cecilius Calvert, the second Lord Baltimore. In recent years, a combination of development and deer has reduced the insect's turtlehead habitat and thus the checkerspot population.
Aided by several small grants and the zoo's hospitality and habitat, volunteers have managed to breed dozens of caterpillars since last summer. Some even escaped into Druid Hill Park, starting a wild colony there.
But when Durkin went to the Montgomery County farm where four or five dozen more caterpillars wintered in advance of transfer to the zoo, she found none left.
Durkin thinks pet geese poked holes in the netting over the checkerspot's host plants. The caterpillars escaped through the holes, she said, because when they are getting ready to emerge, their impulse is to move off their host plants.
"I was very, very disappointed," she said. "We'd had so many years of various failures, and we had such a great crop of caterpillars. I had every reason to believe that things were fine."
Even at the zoo, where volunteers worked carefully to catalog daily activities, feed the insects fresh leaves and protect them from predators, some of the growing caterpillars either were killed accidentally or escaped, she said.
"We'll do what we did last year," Durkin said. "Go back out into the wild, collect females and just start again. We've probably made all the mistakes we can make."