The Virginia Department of Game and Inland Fisheries recognizes five species of squirrels within the state. There are two subspecies of northern flying squirrel (Glaucomys sabrinus), two subspecies of southern flying squirrel (Glaucomys volans), four subspecies of fox squirrel (Sciurus niger), two subspecies of gray squirrel (Sciurus carolinensis), and two subspecies of red squirrel (Tamiasciurus hudsonicus).1
red squirrels (Tamiasciurus hudsonicus) prefer coniferous forests
Source: US Fish and Wildlife Service, American red squirrel
Squirrels are famous for burying acorns and other nuts in the fall, then retrieving them throughout the winter as a food source. After initially grabbing 3,000-10,000 nuts each year, a squirrel has to decide whether to eat or cache it. An acorn from a white oak tree is more likely to sprout quickly and become unsuitable food if buried compared to a tannin-rich acorn from a red oak, so squirrels prefer to eat the white oak acorns and bury the red oak acorns.
Squirrels have excellent memories, an essential element in retrieving food buried months earlier in hundreds of different locations. They also have the ability to deceive. When a squirrel senses a competitor is observing its caching efforts and potentially steal its buried food, it can "fake" the deposit of a nut into the cache and then take the food to another location.2
the gray squirrel (Sciurus carolinensis) is easily spotted in city parks across Virginia
Source: US Fish and Wildlife Service, Eastern Gray Squirrel
The Delmarva fox squirrel subspecies (Sciurus niger cinereus) was one of the first 78 species listed in 1967 as "threatened" or "endangered.". At the time, the squirrel was found in just four Maryland counties, occupying just 10% of its historic habitat. Conversion of its preferred habitat of mature forests to farmland, and repeated harvest of trees before a mature forest could be re-established, had reduced the number of squirrels to such a critically-low level that extinction was a serious possibility.
The Delmarva fox squirrel grows to be 50% larger than a grey squirrel and can weigh up to three pounds, so overhunting may have been a significan factor in the population decline. Squirrels were beeding successfully in the remaining occupied territory, but overall populations were not increasing. As part of the recovery effort, hunting of Delmarva fox squirrels was banned in 1971.3
The primary tool for recovery of the species was to trap and transplant a group of individuals to suitable-but-unoccupied habitat. An experimental effort at Chincoteague National Wildlife Refuge in 1968-71 was successful. That led to the initial plan to remove the species from the "threatened and endangered" list:4
The 30 squirrels transplanted to Chincoteague grew to a population which exceeded 300. Squirrels were moved to 17 sites in Delaware, Pennsylvania, Maryland, and Virginia, and in 11 of those locations stable populations were established. Conservation easements on private land were acquired to protect the habitat in perpetuity.
the Delmarva Peninsula fox squirrel (Sciurus niger cinereus) prefers to den in a tree cavity, rather than build a nest of leaves on a branch
Source: US Fish and Wildlife Service, Delmarva Peninsula fox squirrel in tree cavity nest
A 1993 revision of the species recovery plan established a new definition of "success." Delisting would be suitable once 10 translocated colonies were successfully established throughout the historical range, five additional (post-1990) colonies were established, and mechanisms were in place to ensure long-term protection of those populations and the mature forest habitat they required.
By 2015, the Delmarva fox squirrel population had reached an estimated 20,000 and the species had expanded its range to occupy nearly 30% of the Delmarva Peninsula. The US Fish and Wildlife Service, the Maryland Department of Natural Resources, and the equivalent state agencies in Delaware and Virginia celebrated the "delisting" of the species in 2015.5
the once-endangered Delmarva fox squirrel subspecies (Sciurus niger cinereus), found only on the Eastern Shore
Source: US Fish and Wildlife Service, Delmarva Peninsula fox squirrel
one of the two subspecies of gray squirrel is present in every Virginia jurisdiction
Source: Virginia Department of Game and Inland Fisheries, gray squirrel (Sciurus carolinensis carolinensis) and northern gray squirrel (Sciurus carolinensis pennsylvanicus)
Delmarva fox squirrels were translocated to 17 sites, and established new populations at 11 of the reintroduction locations
Source: US Fish and Wildlife Service, Delmarva Fox Squirrel (Sciurus niger cinereus) Recovery Plan, 1993 (Figure 2)