Mammals at
Blackwater National Wildlife Refuge:
Blackwater National Wildlife Refuge is located on the Eastern
Shore
of Chesapeake Bay in Dorchester County, Maryland, about 12 miles south
of Cambridge. Established in 1933, the Refuge consists of over 22,000
acres of brackish marsh, freshwater ponds, and brushy and timbered
swamps.
The wooded areas are predominately loblolly pine and mast producing
hardwoods;
three-square bulrush is the dominant vegetation in the marsh. 
Although the mammals of Blackwater are often overlooked in
favor of
the more abundant and conspicuous bird life, the Refuge hosts a wide
variety
of opossum to the hoofed white-tailed deer.
One species worthy of special note is the large, grizzled
gray Delmarva
fox squirrel. Currently listed as an endangered species, this squirrel
is found only in a few localities on the Eastern Shore. Common on
the Refuge, it is occasionally observed in the woods bordering the
Wildlife
Drive. Forest management programs at Blackwater are oriented toward
perpetuation of this handsome squirrel.
Two other rather unusual residents are the nutria and sika
deer.
The nutria, a large aquatic rodent introduced from South America, is
present
throughout the marsh. Brought into Maryland in the 1940's for use
on fur farms, the nutria eventually reached the wild where they adapted
to the climate of Blackwater. The nutria population continues to
increase and compete with the native muskrat, waterfowl, and other
marsh
residents for habitat resources. They are causing considerable damage
to the wetlands through their feeding activities.
The sika deer, actually an oriental species of elk, was
introduced onto
James Island in Chesapeake Bay about 1916. They are quite common
in southern Dorchester County. Smaller and darker than the white-tailed
deer, often retaining their spots as an adult, this animal prefers the
more secluded areas of the Refuge. 
The following list of 30 species is based on observations by
Refuge
personnel and a report prepared by John L. Paradiso of the U.S. Fish
and
Wildlife Service. Eight additional species are listed as hypothetically
existing on the refuge since it is within their range. Scientific
names and order in which they appear follow Miller and Kellog, List of
North American Recent Mammals (U.S. National Museum Bulletin 205),
while
common names were taken from Burt and Grossenheider, A Field Guide to
the
Mammals. More detailed information on the following species may be
obtained from Paradiso, Mammals of Maryland, North American Fauna, No.
66(U.S. Fish & Wildlife Service, April 1969).
Annotated List of Mammals of the Blackwater National
Wildlife
Refuge:
Opossum
(Didelphis marupialis)
Common in wooded areas and wood margins. Occasionally seen along
roadsides at night. Omnivorous - eats both plant and animal
food.
Masked Shrew
(Sorex cinereus)
Uncommon.
Least Shrew
(Cryptotis parva)
Common in the marsh.
Shorttail Shrew
(Blarina brevicauda)
Common in damp woodland soil habitats.
Starnose Mole
(Condylura cristata)
Common in damp soil.
Eastern Mole
(Scalopus aquaticus)
Common in cultivated fields.
Little Brown Bat
(Myotis lucifugus)
Common. Roosts in hollow trees.
Red Bat
(Lasiurus borealis)
Common in woodlands.
Eastern Cottontail Rabbit
(Sylvilagus floridanus)
Very common in brushy thickets bordering roads and dikes.
Frequently
seen during spring and summer.
Gray Squirrel
(Sciurus carolinensis)
Common throughout Refuge woodlands. Prefers nut-producing
hardwood
trees. More arboreal than the Delmarva fox squirrel.
Delmarva Fox Squirrel
(Sciurus niger cinereus)
Common in wooded areas that contain little or no underbrush.
Distinguished from gray squirrel by its larger size. The
coloration
varies but is usually light gray. This squirrel spends more time
on the ground than the gray squirrel and often feeds in corn and
soybean
fields.
Southern Flying Squirrel
(Glaucomys volans)
Seldom seen because of its nocturnal habits.
Rice Rat
(Oryzomys palustris)
Common throughout the brackish marshes.
White-footed Mouse
(Peromyscus leucopus)
Abundant in wooded and brushy areas.
Meadow Vole
(Microtus pennsylvanicus)
Abundant in marsh where it will build its nest in muskrat houses.
Pine Vole
(Pitymys pinetorum)
Common on all dry land habitats.
Muskrat
(Ondatra zebethicus)
One of the most abundant mammals at Blackwater. Their large
dome-shaped
houses may be seen throughout the marsh.
Nutria
(Myocaster coypus)
Abundant throughout the marsh. Larger than a muskrat, it is sometimes
mistaken for a beaver.
Black Rat
(Rattus rattus)
Uncommon.
Norway Rat
(Rattus norvegicus)
Common.
House Mouse
(Mus musculus)
Common around Refuge buildings and in wild.
Red Fox
(Vulpes fulva)
Common, but seldom seen. Inhabits wooded and brushy areas where
it feeds on rabbits, rodents and birds.
Gray Fox
(Urocyon cinereoargenteus)
Uncommon. Prefers the heavily wooded areas.
Raccoon
(Procyon lotor)
Very common in all wooded areas bordering water. Its varied diet
includes fish, frogs, rodents, eggs, insects and plants.
Longtail Weasel
(Mustela frenata)
Common in brushland, fields, and marsh.
Mink
(Mustela vison)
Uncommon. May be found in all aquatic habitats.
Striped Skunk
(Mephitis mephitis)
Common in brushy areas of Refuge.
River Otter
(Lutra canadensis)
Uncommon, but occasionally seen along banks of Wildlife Drive.
Sika Deer
(Cervus nippon)
Abundant. Found in the more secluded areas of the Refuge.
White-tailed Deer
(Odocoileus virginianus)
Abundant. May often be seen at dusk in tree-bordered
fields.
A Hypothetical Listing of Species Based on Reported Range:
Keen's Bat
(Myotis keenii)
Silver-haired Bat
(Lasionycteris noctivagans)
Eastern Pipistrell
(Pipistrellus subflavus)
Big Brown Bat
(Eptesicus fuscus)
Hoary Bat
(Lasiurus cinereus)
Evening Bat
(Nycticeius humeralis)
Southern Bog Lemming
(Synaptomys cooperi)
Meadow Jumping Mouse
(Zapus hudsonius)
