Could it be they're not smart enough to realize the danger, or clever enough to remember they can get a free meal of corn in the cage and suffer no real harm? Whatever the case, over time they've spread out to where they now cover 28 percent of Delmarva, and more sightings come in every year. Wildlife officials estimate there are 17,000 to 20,000 Delmarva fox squirrels on the peninsula, and believe now that their habitat is sufficiently protected to ensure that the species has a promising future.
Not everyone is convinced. Noah Greenwald, endangered-species director with the Center for Biological Diversity, said that while he's glad the squirrel has come back, he believes it "premature" to declare victory.
The environmental group would support a more gradual easing, he said, by "down-listing" or reclassifying the squirrel as threatened, a less severe status.
"But given the ongoing threats from urban sprawl and sea level rise," Greenwald added, "it doesn't make sense to remove protections altogether."
Keller said sprawl and sea-level rise, which is expected to inundate much of the Blackwater refuge, could put a serious dent in the population, but federal biologists have concluded neither would threaten the species' survival. State laws, land acquisitions and easements on private land mean much forestland is preserved, and the squirrel has spread into areas less vulnerable to rising waters.
The wildlife service is preparing to formally propose de-listing the squirrel, possibly as early as this summer, Keller said. A final decision will be made after receiving public comment and further reviewing the situation. Even then, she explained, plans are to continue monitoring the population.
The squirrel's recovery is evidence that the often-controversial Endangered Species Act can work, said Joe Roman, a researcher at the University of Vermont and author of a recent book on the law's application. De-listing doesn't happen often, he pointed out, and experts believe that the vast majority of listed species have such small numbers or so little viable habitat left that they'll need constant help to survive.
There are more than 600 animals listed as endangered or threatened and hundreds more proposed or candidates for listing, according to an online "box score" kept by the Fish and Wildlife Service. Only 20 have recovered enough to be taken off the list, such as the bald eagle — though it still enjoys legal protection under different laws.
"We're looking for success stories," Roman concluded. "If the Delmarva is one of them, I think wildlife biologists would be happy to have it."
Delmarva Fox Squirrel
Habitat: Farms and forested areas of Delaware, Maryland and Virginia, including Blackwater National Wildlife Refuge, Chincoteague National Wildlife Refuge and Prime Hook National Wildlife Refuge
Status: Listed as endangered in 1967
Description: Gray coat, short rounded ears; can grow up to 30 inches long
Of note: Spends much of its time on the ground instead of in trees; quieter than most squirrels
Sources: U.S. Fish & Wildlife Service, Maryland Department of Natural Resources