Endangered Species

Federally Listed Species

Delmarva Peninsula Fox Squirrel: Endangered Species Status

Credit:John White Delmarva Peninsula Fox Squirrel.

Beginning in spring, visitors to the Refuge are often treated to good views of Delmarva Peninsula fox squirrel (Sciurus niger cinereus) as they find tempting truffle treats (underground fungi that grows on tree roots) along the roadsides. Enjoy these views, but please SLOW DOWN, especially in the short drive between the fee booths and the Bateman Center. Sadly, a number of squirrels are killed each year by cars. The Delmarva fox squirrel (DFS) is an endangered species inhabiting the refuge's loblolly pine forests. Their coloring is similar to the gray squirrel, but the fox squirrel is larger and more terrestrial than the gray squirrel.

The Delmarva fox squirrel's (DFS) original range stretched from central New Jersey south through eastern Pennsylvania and down the length of the Delmarva Peninsula. As woodland has been cleared for farming and altered by forestry, available fox squirrel habitat has dwindled, The Delmarva fox squirrel (DFS) was listed as federally endangered in 1967 (Federal Register 1967). To encourage species recovery, 34 DFS from Blackwater NWR and Eastern Neck NWR, Maryland were translocated to Chincoteague NWR. DFS release sessions were conducted in 1968, 1970, and 1971. Gray squirrels (Sciurus carolinensis) were trapped and removed from the refuge to reduce interspecies competition.

To monitor DFS population numbers, refuge biologists conduct DFS population assessments every two years. Biologists catch the squirrels in a trap, mark the squirrels with a tag, and then release the squirrels. Staff can statistically compare the number marked squirrels captured with the number of unmarked squirrels captured to determine the population’s size.

DFS population trapping began on the refuge in 1990 in three major locations. In each location, 30-40 traps are placed on the ground in a grid pattern, spaced about 100 meters apart. The “trap line” is marked with orange flagging because traps are small, like a bread container, and hard to see in the underbrush. The traps are “pre-baited” with pecans for at 5 days prior to a trapping session. Meaning they are left open and the squirrels can enter, take the pecan, and exit the trap without being caught. Once the trapping session begins, the traps are checked twice daily: once in the morning and once in the afternoon. At the end of the day, traps are closed so squirrels are not trapped overnight.

Credit USFWS Biologists check to see if the squirrel is marked with a Passive Integrated Transponder.

When a squirrel is captured, biologists take the weight, determine the sex and age, and then with a scanner (Mini Portable Reader, Destron Fearing) check to see if the squirrel is marked with a Passive Integrated Transponder (PIT tag). PIT tags are the staff’s method of marking individual squirrels with a unique number. Each PIT tag contains a 10 digit reference number associated with a particular squirrel. The scanner sends radio waves that create a response from the microchip in the Pit tag. If the squirrel doesn’t have a PIT tag, biologists insert a tag under the skin. The PIT tag is about the size of a grain of rice and is similar to “microchips” used for house pets like dogs and cats. Trained refuge staff performs the Pit tagging, but many Refuge Volunteers assisted in recording data and setting trap lines.

Biology staff, with the aid of many volunteers, monitored the Delmarva Fox Squirrel (DFS) population on the Refuge during October and November 2008. Within the three areas studied (Lighthouse Ridge, White Hills, and Woodland Trail), a total of 58 unique, individual squirrels were captured. Of these, fifteen squirrels had been captured and tagged during previous studies, one as long as eight years ago! New “unmarked” squirrels received PIT tags, which identifies each squirrel as a unique individual.

By consulting a mathematical model which uses the ratio of “marked” to “unmarked” squirrels and capture probabilities, we can come up with a population estimate. The 2008 population estimate of Delmarva Fox Squirrels in the three areas sampled was 155. This compares to population estimates of 148, 107, and 144 in years 2004, 2003, and 2001, respectively. The total population for the entire Refuge is estimated at 200. We therefore conclude that this endangered species continues to do well forty years after they were transplanted to the island.

USFWS Chesapeake Bay Field Office DFS Website: http://www.fws.gov/chesapeakebay/dfox.htm
Delmarva fox squirrel factsheet: http://www.fws.gov/endangered/factsheets/squirrel.pdf

Atlantic Coast Piping Plover: Threatened Species Status

Credit: Jeb McConnell Atlantic Coast Piping Plover

Atlantic Coast piping plovers (Charadrius melodus) are a small, sandy-colored bird with a black band on their forehead and neck, orange bill with a black tip, and orange legs. Piping plovers are solitary ground nesters which prefer to nest in sparsely vegetated, sand-flats, shell-flats, and sand-spits on coastal beaches from Canada to North Carolina. Plovers form nests by scraping shallow depressions in the sand with their breasts, wings, and feet. Plovers line the depressions with tiny stones or pieces of shell. Plovers lay up to four eggs per nest and both males and females incubate the eggs for an average of twenty-eight days. Piping plovers rely on cryptic coloration to hide from predators while sitting on their eggs. Nesting in open areas free of visual obstruction allows the parents to see predators coming. Piping plover chicks are precocial and leave the nest shortly after hatching. The plover chicks rely on both parents to lead them to food sources, as shelter from hot and cold temperatures, keep them dry in the rain, and for protection from predators. Piping plover chicks learn to fly or fledge within twenty-five days.

The tiny piping plovers use distraction and secretive behaviors to breed successfully. Instead of attacking predators like terns, piping plovers distract predators by calling or feigning a broken wing to lure a threat away. Piping plovers will also secretly slink away from a nest or their chicks to avoid detection by a predator and return when the threat has passed. Pedestrians, over-sand vehicles, and predators will cause piping plovers to flush from nests or leave their chicks. As plover parents leave nests or chicks to lure a threat away, the eggs and chicks are exposed to other predators and unfavorable temperatures. Frequent disturbance may also lead to abandonment, resulting in lowered hatching and fledgling numbers.

Credit: Jeb McConnell The tiny piping plovers use distraction and secretive behaviors to breed successfully.

In 1985, the Atlantic Coast piping plover was listed as federally threatened under the Endangered Species Act (Federal Register 1985). Despite a population increase from 790 plover pairs in 1986 to 1,890 plover pairs in 2007, degradation of habitat, human disturbance, and intensified predation pressure continue to be limiting factors for piping plovers and other beach dependent birds on the Atlantic seaboard. Limiting factors have reduced the amount of optimal breeding habitat available and caused disturbance, which contribute to poor reproductive success of piping plovers and other beach nesting species. For example, construction of resorts, homes, and coastal engineering such as jetties and seawalls reduced piping plover nesting. Peak beach visitation occurs from April to September and coincides with breeding of the beach nesting piping plover. Piping plovers will alter their habitat selection and feeding behaviors in response to the number of humans on a beach. Food and garbage left by recreational users or resorts attracts mammalian and avian scavengers, which also prey on the nests and young of shorebird species. Depredation is a major cause of the reduction of recruitment and production of ground-nesting birds.

USFWS Atlantic Coast Piping Plover Website:  http://www.fws.gov/northeast/pipingplover/
Piping Plover Factsheet: http://www.fws.gov/northeast/pipingplover/pdf/plover.pdf

The Atlantic Loggerhead Sea Turtle: Threatened Species Status

Credit: John White Atlantic Loggerhead Sea Turtle.

The Atlantic loggerhead (Caretta caretta) sea turtle is a federally threatened species that nests rarely on the refuge. Although, loggerhead sea turtles do not nest on the Chincoteague NWR each year, nesting activity has increased since the year 2000. The turtle’s successful return may be linked to a recovery project that took place more than 30 years ago. Between 1969 and 1979 loggerhead sea turtle eggs were moved from more southern parts of their range such as Cape Romain NWR, SC and allowed to hatch on local beaches. It takes 30 years for loggerhead sea turtles to reach maturity. Female turtles that were part of the initial recovery project may just now be returning to where they originally hatched.

Atlantic loggerhead sea turtles are found in waters from Canada to Argentina. Loggerheads were named for their large, log shaped heads. Their shell is reddish, brown and can reach 36 inches in length. Male loggerheads can weigh up to 200 pounds. When female sea turtles are ready to lay eggs, they haul their bodies out of the ocean surf and crawl to the sandy beach. The drag marks left my females in the sand are called “crawls” and lead biologists to potential nests.

Credit: USFWS Whenever there is evidence of a potential nest, biologists assemble and go to work.

Whenever there is evidence of a potential nest, biologists assemble and go to work. Measurements are taken of the turtle’s crawl track. The body pit where the turtle had laid as she dug her nest is carefully scrutinized to determine the actual location of the nesting chamber. Biologists then carefully dig in the sand, lifting out one handful at a time until the top layer of eggs is reached, confirming the nest’s existence. Loggerheads lay between 100 to 126 eggs per nest and average 4 nests per breeding season. The sand is replaced quickly and more measurements and photos are taken, and a protective screen is placed over the nest to deter predators. The process usually takes less than 20 minutes. In 2005, two Loggerhead Turtle nests found on Wild Beach hatched, making 2005 the most successful year for turtles found on the Refuge in recent times. Sometimes nests are destroyed by hurricanes before the turtles can hatch. Tropical Storm Ernesto washed out 6 of the 7 nests discovered in 2006 (although one hatchling did survive). Even dead adult turtles that wash onto Refuge beaches receive attention. They are measured and checked for possible causes of death. Boat strikes, drowning in fishing nets, or ingesting plastic which they mistake for food, are common causes of death.

A loggerhead sea turtle nest’s “hatch window” ranges 60 to 90 days after the eggs are laid. Chincoteague NWR is at the northern end of the loggerhead turtle’s range and eggs usually hatch closer to the 90 day mark. These turtle eggs can easily be damaged by people walking or vehicles driving over the nest. The eggs are so sensitive that excessive vibrations within close proximity of the nest can harm the embryos.

Credit: USFWS Eggs hatch over a period of days rather than all at once.

Eggs hatch over a period of days rather than all at once. Because the eggs usually hatch at night, the tiny hatchlings are hard to see and can easily be stepped on or run over. After hatching, though, the tiny turtles immediately make a bee-line for the water. These hatchlings instinctively move toward the brightest spot on the horizon, because in nature, moonlight reflecting off the water draws them in the direction of the sea. Any artificial lighting, such as vehicle headlights, and even flashlights can disorient the hatchlings, luring them away from the sea and safety. In addition, vehicle ruts and other debris can impede their progress, making them vulnerable to predators or trapping them in places where they eventually dry up in the hot sun. Currently, biology staff places materials and signs around nests providing protection from pedestrian and vehicular traffic. White plastic posts, with red and white signs reading, “Area Closed Important Turtle Nesting Site” will warn beach users that they are approaching the sensitive turtle nesting area. Please stay out of areas that are closed to protect turtle nests and other wildlife habitat. Immediately report any sea turtle crawls (marks on the sand where turtles have come onto the beach) to Refuge or Park Service Staff. With your cooperation, future generations of Loggerhead Sea Turtles will multiply in healthy abundance.

NMFS Loggerhead Sea Turtle Website: http://www.nmfs.noaa.gov/pr/species/turtles/loggerhead.htm
Loggerhead Sea Turtle Factsheet: http://www.fws.gov/northflorida/SeaTurtles/Turtle%20Factsheets/loggerhead-sea-turtle.htm

Seabeach Amaranth Plant: Threatened Species Status

Credit: USFWS Seabeach Amaranth Plant.

Seabeach amaranth (Amaranthus pumilus) is an annual plant native the barrier island beaches of North America historically ranging from Massachusetts to South Carolina. The stems are fleshy and pink-red, with small rounded leaves. The shiny, spinach-green leaves are 1.3 to 2.5 cm in diameter. Seabeach amaranth is wind and self pollinated. Seed production begins in July or August and reaches a peak in most years in September. Wind, water, and wildlife serve as seed dispersal mechanisms. The species is found on sandy, sparsely vegetated beaches between the high tide line and the toe of primary dunes.  Seabeach amaranth populations are highly dynamic, with numbers of plants often fluctuating dramatically from one year to the next.

Seabeach amaranth was listed as federally threatened in 1993. Many factors have contributed to the decline of seabeach amaranth plants. Hardening of beach landscapes with seawalls or jetties impede the movement of amaranth seeds along the beach by blocking sand and water. Off-road vehicles (ORV) and pedestrians inadvertently crush adult plants needed to reseed areas. Often, little or no seabeach amaranth is found in areas that receive high ORV use with the exception of areas that are specifically protected by restrictive fencing. Mechanical beach raking can pull out amaranth plants by the roots. Depredation by deer, insects, and feral animals also affects seabeach amaranth populations.

Seabeach amaranth was first documented on the refuge in 1966 by a graduate student. Refuge staff and cooperators observed the plant again in 1967 and 1972, but not seen thereafter. In 2000, the National Park Service (NPS) found seven seabeach amaranth plants in Maryland. The NPS collected offspring from the plants and began a program to restore this endemic species to the beaches. NPS planted the offspring on Assateague Island, MD from 2000 – 2002. Following plantings near the Maryland and Virginia state border, nine plants were discovered on the Refuge in Virginia. Currently, seabeach amaranth surveys are conducted annually by refuge biology staff in conjunction with NPS staff. Staff and volunteers place wire exclosures around amaranth to protect the plants from deer grazing, pedestrians, and vehicles. Seabeach amaranth plants have been observed on the refuge each year since 2001.

USFWS Seabeach Amaranth website: http://www.fws.gov/northeast/nyfo/es/amaranthweb/overview.html
Seabeach Amaranth Fact Sheet: http://www.fws.gov/nc-es/plant/seabamaranth.html