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In 1994, as part of sitewide biological surveys, observations of mammals or evidence of their presence were made seasonally along transects and during timed or time-constrained searches into selected habitats.  Incidental observations of mammals were also recorded while moving from site to site, walking to and from sites, and while cruising roads.  A total of 14 mammal species were identified during observations.   The white-tailed deer was the most common mammal observed by sight.  They were found in all natural habitats and were also seen in developed areas.  Deer were observed feeding on grasses along roadways and lawn edges.   Within forests and wetlands, deer browsed on saplings, grasses, shrubs, and green brier.  This species relies heavily on the annual crop of acorns produced by the various oak species on site.  White-tailed deer were less common in the pine plantation areas than in the pitch pine/oak forest and wetland sites.  Within these areas they were more common near edges where habitats changed, especially mowed grassy edges bordering roadsides.  No deer hunting (gun or bow) is allowed on the BNL property.  Hunting is allowed in cooperative hunting areas adjacent the site to the east.  The hunting restriction has contributed to the large deer population on site.

Other species commonly observed on site but in low numbers were raccoon, muskrat, cottontail rabbits, gray squirrel, eastern chipmunk and red fox.  White-footed mouse and other small mammal signs were observed throughout the site in various habitats except grasslands and mowed areas.  Individual meadow voles or indications of their presence were observed in fields and emergent wetland areas where they are common.   Other species including woodchuck, pine vole, and meadow jumping mouse were also observed on site.

Except for white-tailed deer, most mammals, including eastern cottontail, woodchuck, gray squirrel, and eastern chipmunk, were less common than expected on the BNL site.  Certain species such as mink and weasel may be on site, but probably in very low numbers, as no evidence of their presence has been observed.  Opossum and striped skunk were not seen during surveys, but have been observed by field sampling teams.

Selected Larger Mammals (alphabetical order by common name)

Eastern Cottontail Rabbit (Sylvilagus floridanus)

The eastern cottontail rabbit inhabits farmland, pasture, open woodlands, swamps, and marshes.  It feeds on grasses and herbs during the summer and twigs, buds, and bark of shrubs and tree saplings in the winter.  Brush piles, thickets, and abandoned woodchuck burrows are used for cover.  Three to four litters are produced annually with 3-8 young produced per litter.

Cottontails are most active at night and their presence/numbers may often be under reported.  They were most often observed in evenings feeding on lawns, or adjacent to the roadways at the edges of the recreation fields and open fields.  Droppings were observed within the grassed portions of the gamma forest.  Chief predators are the same as those for the gray squirrel, though feral domestic cats may also prey on cottontails. 

Gray Squirrel (Sciurus carolinensis)

Gray squirrels inhabit dense forests, suburban developments (where there is tree cover), and city parks.  They are diurnal; have one or two litters per year (yielding one to seven young); and eat nuts, berries, seeds, mushrooms, and buds (DeGraaf & Rudis, 1983).  In autumn, squirrels often move home ranges short distances to areas with greater food supply.

Gray squirrels were not commonly observed on the Brookhaven property.  They were most often observed within and adjacent to the dense red maple stands in wetlands.  Many of the large red maples in wetlands have cavities or hollow trunks that gray squirrels use as winter dens.  Few summer nests (leaves and branches) were observed.  Likely predators of the gray squirrels are the red fox, red-tailed hawk, and great horned owl.  The gray squirrels on the BNL property are likely dependent upon an annual crop of acorns as a food supply, though they were also observed in fall 1994 feeding on ears of corn within the west ecology field. 

Raccoon (Procyon lotor)

Raccoons are common on the BNL site. Tracks were found adjacent to the wetlands, particularly the RHIC wetland, and the ecology field ponds. BNL personnel stated raccoons are often observed foraging on developed portions of the site.

Feral Cat (Felis domesticus)

Domestic cats were observed on the BNL site.  Some of the cats observed hunting on the site may have been pets from residences north of BNL property; others appeared to be semiwild or feral.  It is expected that the feral cats prey on small mammals and ground-nesting birds.

Gray Fox (Urocyon cinereoargenteus)

Gray foxes were confirmed on the BNL site in 2006. The gray fox is the only canine that can climb trees. During 2006, an adult and kit (juvenile) were seen on the eastern side of the BNL property. In 2007, 2 adults and 2 kits were observed. Little is known about the population of gray fox on Long Island. A study is currently being done to determine the population and home range of the individuals living onsite.

Red Fox (Vulpes fulva)

Red foxes were observed several times on the BNL site, and tracks and droppings were commonly observed on the firebreaks and unpaved roads.  A vixen (female) was observed on 10 June 1994 in the tree dump near a den located in logs; several foxes, including pups, were observed in September 1994.  As the typical home range for red fox is 1-2 square miles (Burt & Grossenheider, 1976), it is probable that the individuals inhabiting the site derive a significant portion of their food supply (small rodents, birds) from the BNL property.

White-tailed Deer (Odocoileus virginianus)

See Deer page

Woodchuck (Marmota monax)

Woodchucks prefer dry woods, fields, pastures, mowed roadsides, and lawns and are diurnal (most active in early morning or late afternoon).  Woodchucks dig a series of burrows and dens, which are often used by other mammals (not as cohabitants) such as fox, raccoon, and cottontails.  Preferred food includes clover, alfalfa, timothy, and perennial plants.

Woodchucks were commonly observed on the developed portions (open fields, ballfields; adjacent to buildings) of the BNL site.  Several runways (trails in grass and beneath fences) and burrows were found adjacent to the east ecology field, and one family was observed adjacent to Brookhaven Avenue near the ballfields. While the pitch pine/oak forest is relatively poor habitat for woodchucks, the development of the site and maintenance of large cleared/mowed areas has probably encouraged growth in their numbers.   With the exception of the red fox, the woodchucks appear to be free of predators.   The home range for the individuals observed is likely the BNL property.

Small mammals (alphabetical order by common name)

Eastern mole (Scalopus aquaticus)

The eastern mole is the most common mole on Long Island.  Though it is most abundant in mixed deciduous woods where soils are moist and rich, the eastern mole tends to avoid wetland areas.  The pitch pine/oak areas of BNL contains soils which are typically dry and sandy; habitat also suitable for this mole (Connor, 1971).   Evidence of moles (pushed up soil runways) was not common on the BNL site.   They feed on a variety of soil invertebrates, including worms, grubs, insects, and small salamanders (Connor, 1971) and young are produced from late April to May (DeGraaf and Rudis, 1987).

Evidence of eastern moles was most commonly found in areas adjacent to wetlands and moist woods.

Masked Shrew (Sorex cinereus)

The masked shrew is common on Long Island in most habitats with sufficient ground cover (Connor, 1971).  Specimens were collected in wet to dry habitats such as old fields, shrubby fields, forests and wetlands. Connor (1971) found the masked shrew produced young from April through October.  Masked shrews eat a variety of foods including worms, spiders, snails, slugs, and some vegetable matter (DeGraaf and Rudis, 1987).

During the small mammal trapping survey, five masked shrews were collected.  An overall average of 176 trap-nights of effort were needed to collect one masked shrew.   Masked shrews were only collected at wetland transects; here the effort required to collect one specimen fell to 76.6 trap-nights of effort.  Terrestrial transect yielded one masked shrew in an unbaited pit trap. All other terrestrial transacts had evidence of shrew presence (small burrows).  This species is present on site in most habitats but appears to be relatively uncommon.

Meadow vole (Microtus pennsylvawcus)

The meadow vole is abundant on Long Island in grass and sedge areas but does not usually occur in other habitats (Connor, 1971). Young are produced throughout the year (DeGraaf and Rudis 1987). Meadow voles eat a variety of vegetable material, including grasses, bulbs, cambium (surface layer) of roots and stems, seeds, grains, and some invertebrates (DeGraaf and Rudis, 1987).

During small mammal trapping survey, 10 meadow voles were collected.  An average of 88 trap-nights of effort were needed to collect one meadow vole.  Within old field and herbaceous wetland habitats, only 26 trap nights of effort were needed to collect one meadow vole, indicating its apparent preference for these habitat types.

Pine vole (Microrus pinetorum)

The pine vole is common on Long Island, where it prefers pitch pine/oak forests as well as other habitats, including deciduous forests, grasslands, meadows, and wetlands with a heavy ground cover of leaves or grass (Connor, 1971 and DeGraaf and Rudis, 1987).   This species is fossorial (burrowing), and feeds on a variety of foods, including tubers, roots, bulbs, bark, leaves, seeds, nuts, fruits, and invertebrates (Connor 1971, DeGraaf and Rudis 1987).  Reproduction occurs from April through September (Connor, 1971).

One pine vole was collected in pitch pine/oak habitat of terrestrial .  Two other pine voles were found on-site, one dead in the pine plantation and another in the vicinity of the ecology fields.  This species presence onsite probably uncommon.

Southern flying squirrel (Glaucomys Volans)

The southern flying squirrel is common in suitable habitats on Long Island, such as pitch pine/oak, pine, and southern white cedar forest and wetlands (Connor, 1971).   This species is strictly nocturnal, feeding on a variety of nuts, fruits, and seeds including, pine cones and acorns (DeGraaf and Rudis, 1987).  Young are produced from April to August (DeGraaf and Rudis, 1987).  Three southern flying squirrels were captured during the small mammal trapping survey, one in a white pine plantation and the other two in moist pitch pine/oak wood.  The southern flying squirrel appears to be common onsite in suitable habitats.

White-footed mouse (Peromyscus leucopus)

The white-footed mouse is very common on Long Island, where it occurs in most habitats, including fields, pine plantations, deciduous forests, pitch pine/oak, and wetland areas (Connor, 1971).  The white-footed mouse feeds on a variety of foods, including seeds, acorns, nuts, fruits, green plants, insects, and carrion (DeGraaf and Rudis, 1987).   They reproduce from April through October (Connor, 1971).

White-footed mice were the most common small mammal collected during the 1994 small mammal trapping study.  This species was most common in the moist forests and wetland areas along the Peconic River and its tributaries.  Seven trap nights of effort were required to collect one individual.  In wetland areas, five trap nights of effort were required to collect one individual, compared to nine trap nights of effort to collect one individual in pitch pine/oak forests and pine plantations.  This indicates the species preference for wetland areas.

Deer Raccoon
Deer Issues Ground Hog
Lyme disease Feral Cats
Forest regeneration Bats
Red Fox Skunks

Reference: December 1994; Sitewide Biological Inventory, Phase II.
Note: Text citation may be found in the above reference document.

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Last Modified: November 14, 2008
Please forward all questions about this site to: Karen Ratel