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Nearing the finish line: Delmarva Peninsula fox squirrel recovery.

A member of the class of 1967, the Delmarva Peninsula fox squirrel (Sciurus niger cinereus) was among the first animals considered to be threatened with extinction. Now, after 40 years of federal protection, the fox squirrel's population is increasing, its range expanding, and the prospect for recovery is bright. A 2012 status review found that the species has rebounded so well, that the U.S. Fish and Wildlife Service (Service) is preparing to propose to remove the squirrel from Endangered Species Act protection.

Catching a glimpse of this large, silver-gray tree squirrel was once rare within the forests connecting Delaware, Maryland, and Virginia. By the time the fox squirrel was protected by federal law in 1967, it was found in only a handful of counties in Maryland--just 10 percent of its historic range. Today, the squirrel's range has increased to 10 counties, with a current population of about 20,000.

Distinguishing the Delmarva fox squirrel from the common grey squirrel is not difficult after you have seen a few. This Delmarva Peninsula native can grow to be nearly twice the size of its common relative, with a broad head, short ears, and a wide fluffy tail. It prefers mature forests of mixed hardwoods and pines, especially those bordering farm fields--a rural landscape that is still abundant on the Delmarva Peninsula.

The squirrel's decline in the mid-1900s was fueled by many factors; forests were cleared for farms and development, and short-cycle timber harvests depleted mature woodlands. Over- hunting of Delmarva fox squirrels may have also played a role in the species' decline.

After the species was listed as endangered, federal and state biologists, researchers, conservation groups, and private citizens worked to boost populations, monitor progress, develop new conservation tools, and conserve habitat. State and federal biologists focused on increasing the squirrels' distribution by establishing additional populations within its historic range, and officials closed the hunting season to reduce the threat of over-hunting. Several private citizens owning large farms played a key role in these efforts.

"We've worked with several landowners who were more than willing to have squirrels translocated onto their property," says Glenn Therres, Associate Director of Maryland Department of Natural Resources Wildlife and Heritage Service. "We have been monitoring the squirrels for many years now, and they have really done well."

National wildlife refuges were also instrumental to the recovery. Chincoteague NWR in Virginia and Prime Hook NWR in Delaware both host translocated Delmarva fox squirrel populations. Maryland's Blackwater NWR, which is in the heart of the Delmarva fox squirrel distribution, was the source for many of the translocated animals, and continues to provide sites for long-term monitoring and research.

Trapping and camera surveys have recently led to the discovery of new Delmarva fox squirrel populations, indicating that the species' range is expanding--covering nearly one third of the Delmarva Peninsula. The animal has also been spotted by knowledgeable observers who live and work in the area. A network of state and federal biologists, foresters, hunters and other knowledgeable citizens has been critical to understanding the range.

"Being a forester allows me to be in the woods more than most people, and so it's not uncommon to occasionally bump into a fox squirrel," says Dan Rider of the Maryland Department of Natural Resources. "About 10 years ago I saw one where I knew none had existed previously. That was exciting. Even more exciting has been watching that small group of squirrels increase in numbers each year."

While some of the forest occupied by the squirrel is on federally or state-owned land, more than 80 percent of this squirrel's home is on private land. Fortunately, this animal can thrive on the working landscapes of farms and woodlands that are common on the Delmarva Peninsula. It is commonly seen along forest-field edges where it can help itself to the harvest. It also can tolerate some timber harvest, as long as sufficient acreage of mature forest remains nearby.

"We keep our fields in production and in our forests we routinely harvest timber and do other intermediate practices," says Lin Spicer, a long-time resident of Maryland's Eastern Shore. "We've enjoyed seeing the fox squirrels year after year, and regard them as something unique to our area. It's sort of a badge of honor. We can keep our land productive while giving these unique animals a home."

Mature forest is the key habitat component for this species, but maps of this mature forest habitat were not available until a recent collaboration of scientists from the Service's Chesapeake Bay Field Office, the Goddard Space Center, and skilled contractors from Sewell. Light Detection and Ranging (LiDAR) data was used to construct maps that delineate mature forest, suitable for fox squirrels, from young regenerating stands.

It also helped that the timber industry on Delmarva Peninsula changed from short rotations to produce pulp and paper to longer rotations to grow sawtimber. This preference for older, more mature trees created more suitable habitat for Delmarva fox squirrels. In addition, 58,000 acres (23,471 hectares) that were once industry owned and managed for small trees, are now owned by the state of Maryland and managed for sawtimber with specific management to benefit the Delmarva fox squirrel.

Over 90 percent of the forest that was occupied by Delmarva fox squirrels as of 1990 continues to be occupied 20 years later. The range of Delmarva fox squirrels is now large enough and well distributed to withstand current and future threats. This success story simply would not be possible without the combined efforts of the citizens of the Delmarva and the many partners committed to recovery.

Caption: Delmarva fox squirrels inhabit mature forest of mixed pines and hardwoods and a relatively open understory.

Caption: U. S. Fish and Wildlife Service biologist Cherry Keller sets up a Delmarva fox squirrel monitoring site. These squirrels are primarily surveyed with remotely triggered cameras, or trail cams.

Caption: A motion-triggered camera captures the image of a Delmarva Peninsula fox squirrel.

Editors note: Learn more about this species' remarkable recovery at the Delmarva fox squirrel website.

Cherry Keller, an endangered species biologist in the Service's Chesapeake Bay Field Office, may be reached at cherry_keller@fws.gov or 410-573-4532.

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Author:Keller, Cherry
Publication:Endangered Species Bulletin
Geographic Code:1USA
Date:Jan 1, 2014
Words:1042
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