Saugus Iron Works National Historic Site

Saugus Iron Works National Historic Site


Numerous species of amphibians, birds, fish, mammals, and reptiles utilize the Saugus River and surrounding wetlands and riparian woodlands within Saugus Iron Works National Historic Site as an important refuge to thrive and reproduce. Some animals are seen for brief periods, while others make the historic site their home throughout the year.

During the spring, the red-winged blackbirds and mallards prepare their nests within the tall wetland grasses, while the barn swallows return to the Iron Works to begin raising a new generation. In early summer, the snapping turtles lay their eggs, while the muskrats playfully swim in the cool waters of the Saugus River. Great blue herons and black-crowned night herons perch atop the maples and hickories along the winding river in search of the elusive alewife as the Atlantic Ocean tide slowly moves upstream, inundating the wetlands.

As the summer slowly disappears for the year, spotted sandpipers can be seen hopping about the river mudflats while the barn swallows teach their young how to fly swiftly before their long journey south to warmer climates.

Each animal, as well as many others whose stories have yet to be told, is an important part of the complex ecosystem within Saugus Iron Works.


Saugus Iron Works National Historic Site is the home of over 37 species of birds. The more common native bird species found here include the American crow (Corvus brachyrhynchos), American robin (Turdus migratorius), gray catbird (Dumetella carolinensis), yellow warbler (Dendroica petechia), common yellowthroat (Geothlypis trichas), song sparrow (Melospiza melodia), northern cardinal (Cardinalis cardinalis), and red-winged blackbird (Agelaius phoeniceus).  These bird species may be found in all three major habitat types within the historic site. These habitat types are broadly classified into landscaped areas, wetlands, and riparian woodlands.

Saugus Iron Works is also home to three species of non-native birds, including the rock dove or domestic pigeon (Columba livia), European starling (Sturnus vulgaris), and house sparrow (Passer domesticus). These bird species are native of the European continent.

Some of the native perching birds that spark the interest of park visitors include the barn swallow (Hirundo rustica), Baltimore oriole (Icterus galbula), and American goldfinch (Carduelis tristis).

Many species of birds can be seen occasionally within the Saugus River, including the mallard (Anas platyrhynchos), Canada goose (Branta canadensis), black-crowned night heron (Nycticorax nycticorax), great blue heron (Ardea herodias), and belted kingfisher (Megaceryle alcyon).

Saugus Iron Works also has two species of native woodpeckers: the downy woodpecker (Picoides pubescens) and northern flicker (Colaptes auratus).


Two species of amphibians have been seen at Saugus Iron Works National Historic Site, the green frog (Rana clamitans melanota) and the northern two-lined salamander (Eurycea bislineata bislineata). Although it is believed that the green frog does not actually breed within the historic site, this frog can be seen occasionally within the Saugus River wetland and the sluiceways of the Iron Works during the spring.

Unlike the green frog, the northern two-lined salamander has been observed breeding within Saugus Iron Works. These reclusive amphibians frequently seek shelter under logs, stones, and other objects near seeps, springs, and the Saugus River. It is within these sheltered areas that the female salamander lays her eggs.


Presently, three species of reptiles have been identified within Saugus Iron Works National Historic Site, the eastern garter snake (Thamnophis sirtalis sirtalis), the northern brown snake (Storeyia dekayi dekayi), and the common snapping turtle (Chelydra serpentina). These reptiles are pretty elusive and are able to camouflage themselves within the wetland areas bordering the Saugus River.

The eastern garter snake and the northern brown snake can be seen from early spring through summer and fall where they inhabit marshes, woodlands, hillsides, streams, and drainage ditches.

While the garter snake and brown snake can be seen over a long period of time through many seasons, the common snapping turtle makes its appearance for a very short time during the summer. During this period, female snapping turtles slowly emerge from the protective waters of the Saugus River, locate suitable nesting areas in gravel and sand, and lay between twenty and forty eggs before returning to the river.  Many of the eggs are eaten by raccoons before the turtles have the chance to develop; however, the small turtles that do manage to survive quickly find their way back to the Saugus River, where they will mature and reach weights of up to 35 pounds. These turtles, in turn, will repeat the circle of life, ensuring the survival of the species for future generations.


At least nine species of native mammals have been observed within Saugus Iron Works National Historic Site. The most common mammal found here is the eastern gray squirrel (Sciurus carolinensis) where it can be seen daily throughout the year within the riparian woodlands and the landscaped areas surrounding the historic buildings. Two other mammals that are closely related to the eastern gray squirrel can also be seen within Saugus Iron Works, the eastern chipmunk (Tamias striatus) and the woodchuck (Marmota monax).

Several species of mammals depend upon the Saugus River as an important habitat and food source. The muskrat (Ondatra zibethica), raccoon (Procyon lotor), and river otter (Lutra canadensis) can be occasionally seen within the river and surrounding marshes.

Other mammals that have been observed within Saugus Iron Works include deer mice (Peromyscus maniculatus), striped skunks (Mephitis mephitis), mink (Mustela vison), and bats (Chiroptera).


The Saugus River and its tributaries are home to many species of fish. Some are true freshwater species, such as redfin pickerel, white sucker, yellow perch, and bluegill. Other species may be found throughout the year in brackish water estuaries (mixture of freshwater and saltwater) , such as sticklebacks and mummichogs.

Several fish species spend a part of their lives in the ocean. The alewife, blueback herring, and rainbow smelt are anadromous fish. They swim up rivers and streams from saltwater to freshwater from late winter through spring to spawn. In the fall, young fish swim back to the ocean where they mature. The American eel is known as a catadromous fish. They spawn in oceans and their young migrate towards freshwater to feed and mature.

Alewives and other anadromous fish species were an important food source for Native Americans and early European settlers. Early fishermen built weirs or small dams in the river using nearby stones. These weirs helped fishermen capture alewives by the thousands. Fishing quickly grew as a profitable industry from the 17th century through the middle part of the 19th century. Fisherman caught and sold bass, shad, alewives, perch, smelt, and eels. There were so many fish in the river during this time that large quantities were collected in scoop nets. During the early part of the 19th century, fish were routinely caught on the “Cinder Banks” at the head of the tidewater of the Saugus River. The “Cinder Banks” area is now known as the slag pile, a primary feature of the historic landscape at Saugus Iron Works National Historic Site.

Within the last twenty years, two major fish inventories were conducted within Saugus Iron Works National Historic Site.  The first major inventory was completed by Hudsonia, an environmental research institute, in 1989. Hudsonia found four species of fish, including American eel (Anguilla rostrata), four-spine stickleback (Apeltes quadracus), white sucker (Catostomus commersoni), and mummichog (Fundulus heteroclitus). The second major fish inventory was conducted in 2004 by the University of Rhode Island. This study listed eleven species of fish. In addition to the four species previously surveyed by Hudsonia, the University of Rhode Island discovered alewife (Alosa pseudoharengus), brook stickleback (Culaea inconstans), redfin pickerel (Esox americana), three-spine stickleback (Gasterosteus aculeatus), large mouth bass (Micropterus salmoides), white perch (Morone americana), and nine-spine stickleback (Pungitius pungitius). The data provided by these surveys enables the National Park Service staff at Saugus Iron Works to better understand, manage, and protect the various fish species found within the Saugus River watershed.

Additional fish inventory and monitoring projects will continue in the near future. Beginning in the spring of 2005, the National Park Service will partner with the Saugus River Watershed Council, the Corporate Wetlands Restoration Partnership, and the Massachusetts Division of Marine Fisheries to conduct a rainbow smelt (Osmerus mordax) and American eel spawning survey within the river. This project will provide new smelt and eel population and habitat information to state and federal fisheries biologists.