Naturalist Fact : Virginia Opossum (Didelphis virginiana)  

virginia-opossum

 

A common mammal species throughout the Eastern and Midwestern US, the Virginia Opossum is the only marsupial to live North of Mexico.  They range from southern Canada to northern Costa Rica with some populations found in California presumably brought there by travelers as a food source during the depression.  Although they are also commonly referred to as just possums in Georgia, the term possum is technically used to refer to a specific suborder of arboreal marsupials found only in Australia, and Opossum refers to new world marsupials found in North and South America. The term opossum was actually borrowed from the Algonquian name for them, aposoum, meaning “white dog”. The average Virginia Opossum is about 2 feet in length weighing around 8 pounds; female opossums are smaller than males, with male opossums ranging 12 to 15 pounds. They have a very short lifespan, typically only surviving a year in the wild. Like most marsupials the female Virginia Opossum has a pouch which is lined with fur where the young develop. A female Opossum can give birth to as many as 20 young, which at birth are not much larger than a honeybee, about a half an inch in length. Upon their birth they must crawl to the pouch of the female and attach themselves to one of the 13 teats within the mother’s pouch. After about 60 days the young will leave the pouch and travel on their mothers back until about 100 days of age where they are then independent and can forage on their own. Virginia Opossums are generally nocturnal, being most active at night, and spend much of their time in the trees, utilizing their furless prehensile tail as a fifth limb to help them navigate their arboreal habitat. They are an opportunistic omnivore, eating anything they can find including fruits, nuts, and carrion, as well as predating on small mammals and reptiles.

Recent studies have found that Opossums play an important role in regulating disease transmission in the habitats where they exist. Researchers experimentally found that half of all ticks introduced to mice were able to attach and feed, while only 3.5% of ticks introduced to opossums would attach. The study found that those ticks that failed to attach where eaten by the opossums during grooming. In field surveys they found that the average opossum carries about 200 ticks, and if that is 3.5% of the ticks that try to feed on an opossum, then the average opossum eats up to or more than 5,500 ticks. These same researchers hypothesize that the removal of opossums can have a profound effect on tick populations and increase transmission of ailments such as Lyme disease to other creatures, including people.

Sea turtle season is underway!

Turtle Tech, Elise Diehl

Georgia Nongame DNR Sea Turtle Technician: Elise Diehl

We are happy to announce the beginning of sea turtle nesting season here on the Georgia coast. Each year from May to August, female sea turtles laboriously crawl out of the ocean under the cover of darkness to deposit their eggs in dry sand. There, the eggs will incubate for about 60 days then hundreds of tiny turtle hatchlings will make their way out to sea.

Most of the nesting sea turtles on Georgia’s coast are loggerhead sea turtles, but so far this year Cumberland and Sapelo have each had a green sea turtle nest, and Blackbeard has had a leatherback nest.

On Little St. Simons Island, we found our first loggerhead nest on May 18th, with a total of 167 eggs! We are now up to seven nests, and are hoping to see nesting activity pick up in the next couple of weeks. Last year, we documented 119 nests!

Each year, LSSI works with the Georgia Sea Turtle Cooperative to monitor and protect turtle nests, and we are happy to have Elise Diehl as our sea turtle technician. Elise rides the entire length of the beach at dawn each day looking for the tracks of nesting females. She documents each crawl and nest she finds, and if necessary will relocate the nests that are in danger of being washed over by the tides too often during their incubation. Each nest is marked and screened with plastic mesh to deter predators, as well. As part of a coast-wide long term genetics project, Elise also takes a sample from each nest.

Elise is originally from Bloomfield Hills, Michigan but has been in Georgia since she was 16. Once she moved to Georgia, she was introduced to sea turtles and wanted nothing more than to work with them one day. While earning her B.S in Wildlife Sciences at the University of Georgia, she worked in the lab analyzing the genetic information being collected from each nest on the Georgia coast. Last summer, Elise monitored nesting turtles on Ossabaw Island. After spending a few months at the Georgia Aquarium, she is excited to be back on the coast for another season!

Naturalist Fact: The Moon

Image Credit: GSFC / Arizona State Univ. / Lunar Reconnaissance Orbiter NASA

Image Credit: GSFC / Arizona State Univ. / Lunar Reconnaissance Orbiter NASA

With little light pollution on Little St. Simons Island, it is a great place to explore the night sky. Although it travels through several phases each month, Earth’s moon is usually the most conspicuous sight in the night sky. The moon’s illumination is the result of the sun’s light reflecting off the moon’s surface, and as the moon rotates around the Earth, we are able to see differing proportions of the moon.

The moon is estimated to be about 4.5 billion years old, about the same age as the earth. The most accepted theory for the formation of the moon, is that while the earth was still very young, a rock comparable to the size of Mars collided with Earth. The impact of this collision sent large pieces of rock into Earth’s orbit, which aggregated into one body to form our moon.

It takes the moon about one month (28 days) to orbit the earth, and it takes about the same amount of time (27.53 days) for the moon to complete a rotation around its own axis. Consequently, the same side of the moon is always facing Earth. Depending on the phase of the moon, we can see a certain portion of that side each night.  At its fullest, we can see a little more than half of the moon (59%). The other 41% is the side that never faces Earth, also known as “the far side.”

The moon’s surface exhibits an interesting array of geographical features. The large dark areas are called seas or maria, and were once huge lava plains. Craters appear much lighter than the maria, and appear like starbursts with lines radiating out from the center. All the craters were formed by meteor collisions. The moon also has mountain ranges, valleys, cliffs, and other changes in topography. The best time to observe these features through binoculars or a scope, is several days before and after the full moon when the angle of the sunlight gives the most definition to its features.

Naturalist Fact: Scarlet Snake

Scarlet-Snake-3

The Scarlet snake (Cemophora coccinea) is an elusive snake, rarely found by humans.  This species is quite slender and reaches a maximum length of about thirty inches.  These snakes always have wide red bands separated by yellow or white bands which are bordered with black.   The bands do not encircle the entire body, leaving the belly of these snakes white or cream-colored.  Often mistaken for a venomous look-alike, the coral snake, there are some morphological differences that can help to distinguish between the two.  Firstly, the red bands do not touch the white or yellow bands, as they do in the coral snake.  Scarlet snakes also have a pointed snout that is red, while coral snakes have a black-tipped snout.

Scarlet Snakes are the only snake species on Little St. Simons Island that is considered nocturnal, which is usually the only time they are observed moving on the surface of the soil or substrate.  These snakes are semi-fossorial, spending most of their time underground.  Occasionally Scarlet Snakes are found in or under logs, boards, tin, rocks, or leaf litter.  The pointed snout and slender body allows them to burrow through dry, loamy, and sandy soils.  These snakes are most commonly found in habitats where this sandy and well-drained soil is predominant, such as pine flatlands, dry prairies, maritime hardwood forests, and sweetgrass prairies.  Scarlet Snakes are found from Southern New Jersey, south to Southern Florida, and West to East Texas.

Reptile eggs make up the majority of the Scarlet Snakes’ diet, but they may also prey on lizards, small snakes, or frogs.  If an egg is too large for a Scarlet Snake to swallow whole, they may break it open with specialized enlarged teeth before swallowing it.  Very little is known about Scarlet Snake reproduction due to the secretive nature and burrowing habits.  In early summer (typically June), female snakes will generally lay 3-9 elongated and leathery eggs underground (1-13/8” long).  The young are about 6 inches long when they hatch in late summer, and closely resemble adult snakes in coloration.

Prescribed Burn, February 2014

IMG_9957

Prescribed burn in wax myrtle/sweet grass habitat. (Photo: Laura Early)

Fire is an important ecological management tool for a variety of habitats, returning nutrients to the soil and reducing woody vegetation and shrubs. Last week, we conducted a prescribed burn in the maritime shrub and grassland habitat between the beach, Bass Creek Road and Beach Road. With the help of local biologists from the local non-game division of Georgia Department of Natural Resources, the Jekyll Island Authority, and the St. Simons Land Trust, the island maintenance staff and ecological management team ignited and controlled a low-burning fire on Tuesday, February 18th to prevent woody vegetation from encroaching on open grassy areas.

Scott Coleman, Ecological Manager igniting broomsedge. (Photo: Laura Early)

Scott Coleman, Ecological Manager igniting broomsedge. (Photo: Laura Early)

This ecosystem adjacent to the beach dunes is dominated by wax myrtles (Myrica cerifera) and Muhly grass (Muhlenbergia capillaris), and left to its own devices, the wax myrtles would continue to recruit eventually closing out the open habitat where the grasses thrive. This burn did not reach an intensity that would take back large established wax myrtle shrubs, but it will reduce wax myrtle cover by preventing young seedlings and saplings from taking hold. The balance of open grassy areas and cover provided by the wax myrtles provide excellent habitat for a variety of species, including the Eastern diamondback rattlesnake, coachwhips, kingsnakes, small rodents, painted buntings, chuck-wills widows, island glass lizards and marsh rabbits.

Other plants that make up this community include: broomsedge (Andropogon spp.), dog-fennel (Eupatorium capillifolium), flat-topped goldenrod (Euthammia tenuifolia), groundsel (Baccharis halimifolia), and pepper-vine (Ampelopsis arborea).

The day after the fire, herbaceous vegetation had been cleared out. (Photo: Laura Early)

The day after the fire, herbaceous vegetation had been cleared out. (Photo: Laura Early)

Over the next couple of weeks and months, we will start to see new growth in the burned areas, and will continue to monitor the burned plot. Another plant community that benefits from fire is the slash pine forest on the southern part of the island, and if conditions are suitable, we hope to burn there this season as well.

Ten days after the burn, the grasses are already showing new growth! (Photo: Willy Hazlehurst)

Ten days after the burn, the grasses are already showing new growth! (Photo: Willy Hazlehurst)

 

Naturalist Fact: Hummingbird Clearwing Moth

Photo Credit: Birds & Blooms

Photo Credit: Birds & Blooms

The Hummingbird Clearwing Moth (Hemaris thysbe) is frequently mistaken for a hummingbird or bee based on the moth’s appearance and behavior. Adult coloration is variable, but a “furry” olive green and burgundy back is common. Its underside is light yellow or white on the thorax, and burgundy on abdomen. The wingspan is 1.6 to 2.2 inches, and the wings always have a dark reddish border with a transparent center. These moths have fast wingbeats, and hovers while collecting nectar with a long feeding tube from flowers.

During its four weeks as a caterpillar, it feeds mostly on honeysuckle, cherry trees, and hawthorns. As a moth, it feeds on a variety of flowers. These moths feed during the day, which is another factor to their mistaken identity. In the southeast, there are two broods with most activity during the summer months.  The largest population of Hummingbird Clearwing Moths is along the east coast ranging from Florida to Maine. A west coast population ranges from Alaska to Oregon.

 

Naturalist Fact: Alligator Gar

 

http://www.thealexandriazoo.com/mAllAnimals.html

http://www.thealexandriazoo.com/mAllAnimals.html

 

Alligator gar (Atractosteus spatula) are a true prehistoric creature that have remained a hearty predator for millions of years. They have been compared with the earliest terrestrial tetrapods which evolved from the ocean during the late Devonian period. Alligator gar are the largest species in the Gar family (Lepisosteidae), reaching up to 400 pounds and 12 feet in length! The rostrum, or mouth of an alligator gar is short and broad with two rows of extremely sharp alligator-like teeth on the upper jaw, unlike other species of gar which contain one row of teeth. These fish have an elongated body with a single dorsal and anal fin posterior near the heterocercal (rounded) caudal fin. A thick row of nonoverlapping and diamond shaped ganoid scales cover the body, acting as an armor layer to protect from predation. Alligator gar are generally dark olive-brown in color, with dark brown fins and a yellow belly. It is easy to spot gar in a body of water because they contain a lung-like gas bladder which they inflate by taking in gulps of atmospheric oxygen from the water surface! This allows them to reach various levels of the water column by inflating and burping out gas from their gas bladder.

It is common to find alligator gar in slow-moving pools and creeks extended from larger rivers, bayous, lakes, and swamps—mainly in the Mississippi Delta. Alligator gar are mainly piscivores, or consumers of fish, but also eat snakes, small mammals, turtles, and birds. Females generally lay 138,000 eggs which cling to vegetation or rocky substrate in which two or three males will fertilize simultaneously. Females can also live up to 50 years, while males only live up to 25 years old!

Naturalist Fact: Northern Gannet

Naturalist Fact

Northern Gannet (Morus bassanus)

northern gannet

The Northern Gannet is a large seabird, and the largest member of the gannet family.  These birds have long, slender, black-tipped wings with wingspans reaching about 70 inches from tip to tip.  Adult birds have yellowish heads and all white bodies (pictured above) while immature gannets are very dark with white spots.  It can take three or more years to attain full adult plumage.

Gannets are well known for their spectacular feeding behavior, which includes aerial plunges from heights up to 130 feet above the water.  Just before entering the water, the wings are pulled behind the back to help to bird penetrate deeper into the water. Once underwater, the gannets will then use their feet and wings to propel themselves further in pursuit of prey.   Most dives are relatively shallow but dives to depths of 72 feet have been observed.  Small, schooling fishes are the most common prey, but gannets will also opportunistically take squid as well.

These impressive predators are colonial breeders, nesting only on the rocky cliffs of offshore islands during the summer.  There are just six colonies of breeding gannets in North America; three colonies exist in the Gulf of St. Lawrence (Quebec), and three off the coast of Newfoundland.  Large nests are constructed of compacted mud, seaweed, grass, and feathers, with excrement being used as cement.  One pale bluish-green egg is laid each nesting season, and chicks are nearly bare when newly hatched.

Winters are spent entirely at sea, and these birds can be seen diving off the beach at Little St. Simons Island in search of prey.  A spotting scope or binoculars may be necessary to observe them as they typically stay far offshore, but on occasion they can be seen within 100 yards of the beach.

Naturalist Fact: Wood Stork

wood stork 1

William Newton/ Cornell Lab of Ornithology

The Wood Stork is a large, white wading bird with black flight feathers. This bird has a long, decurved bill on its bald head. Its wingspan averages 5.5 feet, making it unmistakable in flight.

Wood Storks are the only species of stork breeding in North America. In the United States, they breed from Florida to southern North Carolina. Other breeding sites are in South America, Central America, and the Caribbean. They are social animals, so they nest in colonies and can have up to 25 nests in one tree. Cypress and mangrove are their preferred nesting trees. On average, a pair of nesting Wood Storks and their young consumes 443 pounds of fish during the breeding season.

Due to a decline in population, Wood Storks have been on the Endangered Species List since 1984. The loss of wetland habitat by development, agricultural practices, and water management practices are reasons for their endangerment. Wood Storks are an indicator species for a healthy, wetland ecosystem.

Wood Storks feed mainly on freshwater fish, and use tactilocation to obtain their meals. Tactilocation is feeding by groping with a bill, and not using eyesight. Wood Storks submerge their bill under water, walk slowly, and sweep their bill side to side. When their bill snaps shut on a fish, their 25-millisecond reflex action is the fastest among vertebrates.

William Newton/ Cornell Lab of Ornithology

William Newton/ Cornell Lab of Ornithology