NOAA’s Mallows Bay-Potomac River National Marine Sanctuary works alongside its co-managers, the state of Maryland and Charles County, to support the interpretation of wildlife within the sanctuary waters and surrounding shores. Here’s a look at some of the more common species you may encounter while exploring the area.
The wildlife in Mallows Bay-Potomac River National Marine Sanctuary needs you to be a good steward on your outdoor adventures. Remember to follow the wildlife viewing guidelines.
Birds
Osprey (Pandion haliaetus)
Known as the “fish hawk,” ospreys are mid-sized raptors that live near water. They are powerful fliers, diving at high speeds to catch fish. Ospreys live in the Mid-Atlantic region from March to August, which is their breeding season. At the end of the summer, they fly to Central and South America for the winter. Osprey pairs often return to the same nest every year. In the sanctuary, they often build their nests at the top of trees, or on man-made objects like nest platforms, telephone poles, and shipwrecks.
Bald Eagle (Haliaeetus leucocephalus)
Bald eagles are large birds of prey with a wingspan of 6-7 feet. Adults have a characteristic white head, yellow beak, and brown body. They live near water year-round and feed mainly on fish, but will also eat smaller birds, small mammals, reptiles, and carrion. They often build their nests near water, in large pine or hardwood trees that can hold nests that weigh over 1,000 pounds. Once endangered, they have made a tremendous comeback and are now common in the Chesapeake Bay region.
Double-Crested Cormorant (Phalacrocorax auritus)
Double-crested cormorants are a water bird that are typically seen drying their feathers on the pilings located near the shipwrecks in the sanctuary. Unlike many other waterbirds, their feathers are not waterproof. This allows the feathers to absorb water, adding weight that helps them dive deeper and faster in search of fish.
Great Blue Heron (Ardea herodias)
Great blue herons are tall, bluish-gray birds with a characteristic S-shaped neck and long, pointed bill. They can often be spotted wading in the shallow waters of marshes and wetlands in search of food. They eat mostly fish but will also feed on amphibians, insects, crustaceans and other small animals.
Mammals
American Beaver (Castor canadensis)
One of the most notable mammals in the sanctuary is the American beaver. With webbed feet and a waterproof coat of thick, brown fur, they are well-adapted to living in and around water. Primarily nocturnal, they are not easily spotted in the sanctuary, but their activity makes their presence known. They use trees, sticks, grass, and other debris to make dams in streams, which creates wetland habitat. They live in lodges, or large round structures that they build from sticks.
White-tailed Deer (Odocoileus virginianus)
White-tailed deer are named for their distinctive, fluffy white tail. They use wooded areas for cover, while open areas provide food. They eat nuts and berries, leaves, woody shoots and stems, and grasses. Males are often solitary, while females often travel together with their young.
Raccoon (Procyon lotor)
Raccoons are omnivores and have a varied diet that includes insects, fruits, nuts, and small animals like crayfish, snails, and frogs. They have dexterous front paws with five fingers that they use to manipulate food and objects. They often live along streams, lakes, marshes, swamps, and other damp habitats.
Plants
Paw Paw (Asimina triloba)
Paw paws are small understory trees, meaning they grow in the shade of taller trees. Their fruit, which is the largest edible fruit native to the United States, is a bright yellowish-green color that tastes like a mix of mangoes and bananas. This delicious fruit attracts animals, such as raccoons, squirrels, opossums, and other small mammals. Paw paws are also essential in the life cycle of the zebra swallowtail butterfly, whose larvae primarily eat paw paw leaves.
Eastern Red Cedar (Juniperus virginiana)
Eastern red cedar trees line the road into Mallows Bay Park. This tree is actually a species of juniper and not a true cedar. Small, blue juniper berries grow in late summer. The fruit is eaten by many animals, including the cedar waxwing, which is a bird that is named after the tree.
Pickerel Weed (Pontederia cordata)
Pickerel weed is a freshwater marsh plant that grows along the shoreline of the sanctuary. It grows 2-3 feet tall with large, heart-shaped leaves, and a dark purple flower that blooms from June to September. Marsh plants provide food and shelter for aquatic animals, as well as filter and clean pollutants from the water.
Coontail (Ceratophyllum demersum)
Coontail is one of approximately eleven species of submerged aquatic vegetation, or underwater grasses, that are found in the sanctuary from late spring to early fall. Underwater grasses grow in the shallow waters near the shoreline where sunlight is plentiful. Coontail has long, branching stems covered in fine, feathery leaves. It provides a food source and habitat for fish and other animals, as well as absorbs nutrients and reduces erosion.
Fish
Striped Bass (Morone saxatilis)
Also known as the rockfish, striped bass are a large predatory fish that have dark stripes running along their silvery sides. They are one of the most popular recreational and commercial fish species in the Chesapeake Bay. A population lives in the Chesapeake Bay and its tributaries year-round, while others migrate seasonally. They feed on a variety of small fish and invertebrates. Mature striped bass use the tidal freshwaters of the sanctuary and surrounding area to spawn in the spring, and juveniles live in the shallow areas of tidal rivers through the summer.
Largemouth Bass (Micropterus salmoides)
Largemouth bass are one of the most commonly sought recreational fishing species and are found in all Maryland waters. They are a greenish-gray color with a gaping mouth. They typically feed on smaller fish, crayfish, worms, and frogs. Stable and abundant nearshore grass beds, such as those within the sanctuary, attract and provide habitat for bass in this area.
American Shad (Alosa sapidissima)
American shad is a migratory species found along the Atlantic coast. They are an anadromous species, meaning they travel upstream into freshwater to spawn each spring. This portion of the river is an important spawning ground for this species, and juveniles will remain in freshwater nursery areas in the spring and summer. American shad are protected by the state of Maryland as a Species of Greatest Conservation Need.
Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus)
Atlantic sturgeon are an endangered species that is federally protected. They live in coastal waters and rivers along the East Coast. They are slow-growing, and can reach up to 14 feet long and 60 years of age. They have five rows of bony plates known as scutes that run along their bodies, giving them a unique appearance. They utilize freshwater as spawning grounds and important nursery habitat. Most of the Potomac River, including the waters of the sanctuary, have been designated by the National Marine Fisheries Service as critical habitat for this species.
Reptiles
Northern Watersnake (Nerodia sipedon)
Northern watersnakes are non-venomous, semi-aquatic, and often found in freshwater habitats like streams, ponds, and marshes. They feed on fish, frogs, and other small animals. They are typically gray or brown, with dark bands along their bodies that cause them to be easily mistaken for copperheads.
Northern Red-bellied Cooter (Pseudemys rubriventris)
Northern red-bellied cooters are large river turtles that are about 12-inches long. They have a dark shell and a distinctive red belly. They are often found basking along the edges of streams, ponds, and rivers on rocks or logs, diving into the water when alarmed. They are omnivores that feed on snails, plants, worms, tadpoles, crayfish, and insect larvae.
Eastern Box Turtle (Terrapene carolina)
Eastern box turtles have tall shells with vivid orange and yellow markings that help them camouflage among fallen leaves and woody debris on the forest floor. They can live in marshy meadows, open woodlands, and forest edges, and are often found near streams or ponds. They eat a variety of plants, mushrooms, fruits, insects, fish, eggs, and small amphibians.
Amphibians
Green Frog (Lithobates clamitans)
The green frog is a common species found in shallow freshwater wetlands. It ranges from green to brownish in color, and males have a white or yellow-green throat. Its characteristic call sounds like a banjo string being pulled.
Spring Peeper (Pseudacris crucifer crucifer)
The spring peeper is a tiny frog, averaging only an inch in size. They are a grayish-brown color, with a distinctive “X” marking on their backs. They typically live in marshy woods and wetlands, and breed in freshwater ponds in the spring. They are named for their distinctive mating call, a high-pitched “peep” that males emit once every second during the breeding season. This sound is one of the first signs of spring in the region.
American Toad (Anaxyrus americanus)
American toads range from 2-3 inches in size, and are a brownish color with large dark warts. They can be found in a variety of habitats and typically eat insects and other invertebrates. In the spring, they will breed in shallow ponds and attract mates with a high-pitched call.
Spotted salamander (Ambystoma maculatum)
Maryland is home to over twenty species of salamanders. The spotted salamander is found throughout most of the state, often near vernal pools that it uses to breed in the spring. It is typically 6-7 inches long, with a black body and two rows of distinct yellow or orange spots.
Insects
Zebra Swallowtail Butterfly (Eurytides marcellus)
The zebra swallowtail butterfly has long, narrow wings with distinctive black and white stripes. Their host plant is the paw paw tree, which adults use for reproduction and caterpillars use as a food source. Adults feed on nectar from flowers such as redbud, milkweed, and verbena.
Eastern Pondhawk (Erythemis simplicicollis)
The eastern pondhawk is a small dragonfly species approximately 2 inches in length. It is typically found near ponds, lakes, and other bodies of water. Females and immature males are bright green, while adult males are blue.
Bumble Bee (Bombus spp.)
Over 10 species of bumble bees are part of Maryland’s more than 400 species of native bees. They are large, furry bees that are mostly black with some yellow patches. They nest in the ground, often in abandoned rodent burrows, and are excellent pollinators.
Non-native
Hydrilla (Hydrilla verticillata)
In the 1970s and 1980s, a non-native underwater grass called hydrilla was brought to the Potomac River. Today, hydrilla is the dominant underwater grass in Mallows Bay. It has long branching stems with tiny leaves that have a toothed edge. Hydrilla offers good habitat for wildlife and is protected in the Chesapeake Bay. However, it can grow very thick and block out sunlight, which can crowd out native grasses.
Blue Catfish (Ictalurus furcatus)
The blue catfish is an invasive freshwater fish that was introduced to the Chesapeake Bay in the 1970s. It has a large, blue body and whisker-like barbels around its mouth, and can grow up to 100 pounds. They are opportunistic feeders, eating worms, clams, and small crustaceans, as well as menhaden, blue crabs, and other economically and ecologically important species in the Chesapeake Bay. They are a popular target of recreational and commercial anglers, especially in the Potomac River where they are abundant.
Northern Snakehead (Channa argus)
Northern snakehead is an invasive species in Maryland and Virginia. It has a long, cylindrical body, sharp-toothed jaws, and a mottled green and brown pattern like snakeskin. It eats primarily fish, but will also feed on frogs, crustaceans, and small birds, mammals, or reptiles, negatively impacting populations of several native species. One unique characteristic is that it is able to breathe air using an air bladder that works like a lung. It is a popular recreational fishing species that has inspired many tasty recipes.