Prescribed Burn: February 2015

Muhly Grass on fire. Photo Credit: Lauren Gingerella

Muhly Grass on fire. Photo Credit: Lauren Gingerella

Along the Georgia coast, muhly maritime grasslands (Muhlenbergia filipes) are a rare, but vital ecosystem for a variety of wildlife. With rising sea levels and coastal development, this habitat is diminishing along with some of the animals that call it home. Island glass lizards and Eastern diamondback rattlesnakes, both species of conservation concern in Georgia, Eastern kingsnakes, marsh rabbits, and cotton rats are a handful of species that utilize these grasslands for protection and reproduction.

A section of Muhly grassland near Mosquito Creek burns. Photo Credit: Kirby Farrell

A section of Muhly grassland near Mosquito Creek burns. Photo Credit: Kirby Farrell

 

Muhly grass is an early successional plant species, one of the first species to populate secondary dunes. By burning these grasslands, wax myrtle (Morella cerifera) and groundsel (Baccharis sp.) thickets are reduced, and the area covered by grass is increased. Little St. Simons Island uses fire as a management technique, or tool, in an attempt to balance out the loss of these grasslands at other coastal locations.

 

Lauren Gingerella (L), LSSI's Ecological Technician, and a member of The Orianne Society's fire crew (R), ignite a patch of Muhly grass using a drip torch. Photo Credit: Kirby Farrell

Lauren Gingerella (L), LSSI’s Ecological Technician, and a member of The Orianne Society’s fire crew (R), ignite a patch of Muhly grass using a drip torch. Photo Credit: Kirby Farrell

On February 10 and 11, we partnered with a fire crew from The Orianne Society to burn four grassland locations for Joseph Colbert’s graduate project. Joseph, a Master’s student at the University of Georgia in Dr. Kimberly Andrews’ Applied Wildlife Research Lab, is leading a two-year study on the ecological response to fire in muhly dominant grasslands. He plans on conducting small mammal trail camera surveys, painted bunting point counts, and reptile surveys.

Joseph’s research will aid LSSI and regional conservationists in developing the best management practices for these grasslands.

 

University of Georgia Master's student, Joseph Colbert (L), and his adviser, Dr. Kimberly Andrews (R) Photo Credit: Lauren Gingerella

University of Georgia Master’s student, Joseph Colbert (L), and his adviser, Dr. Kimberly Andrews (R) Photo Credit: Lauren Gingerella

 

 

 

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Naturalist Fact : Virginia Opossum (Didelphis virginiana)  

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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.

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Naturalist Fact: American Mink

American Mink  (Neovison vison)

American Mink

The American mink is a fascinating voracious predator in the Mustelidae family, which includes otters, weasels, badgers, wolverines, and minks.  The Mustelidae family is actually the most diverse family within the order Carnivora.

American mink are an extremely widespread mammal found across North America, ranging from Alaska and Canada through the lower 48 states, with the exception of extremely dry areas of the Southwest.  The American mink has also been introduced to large portions of Europe where it is classified as an invasive species, linked with the decline of several native species including the European mink.   Although often difficult to view due to a secretive nature, the mink is quite common throughout much of its range.  In suitable habitat, populations may reach densities of 9-22 individuals per square mile.  Mink are considered semi-aquatic, and are rarely seen far from a water source such as streams, lakes, swamps, and marshes.  Occasionally mink can persist in dry environments if there is a steady food supply.  The majority of mink populations occur around fresh water, but coastal salt marsh also produces fine habitat for mink, with abundant prey.

Mink are strictly carnivorous, like all members of the Mustelidae family, and have a varied diet.  Typically the diet depends on the type of prey available, and small mammals such as muskrats and rats may be eaten more during the winter months.  Other prey choices can include ducks, seagulls, crustaceans, amphibians, and other waterfowl.  Being excellent swimmers, mink can swim up to 30 meters underwater and dive up to a depth of 5 meters in search of prey.  Mink are mostly active during the night.  An elusive nature combined with cryptic coloration help mink avoid predation, but occasionally they will fall prey to coyotes, bobcat, birds of prey, and snakes.

Male individuals are very territorial with each other, and have home ranges that may overlap with several female home ranges.  Breeding occurs during the winter months, and both females and males may mate with multiple individuals.  Gestation typically last from 45 to 75 days, and average litter size ranges from 1 to 8 kits are usually born in April or May.  Most kits become independent and find new territory from 6 to 10 months of age, and both male and females become sexually mature around 10 months of age.

The dense and fine pelage (fur) of mink makes it among the most important furs on the fur market.  Historically all pelts came from trapping wild populations which led to declines in populations, but most pelts in the fur trade are now produced on farms.  Wild populations have since recovered from the extensive wild trapping and are considered of least concern by the IUCN (International Union for Conservation of Nature).

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Naturalist Fact: Manatee

Manatee (Trichechus manatus)

http://animalscamp.com/wp-content/uploads/2011/11/Florida-Manatee.jpg

From: http://animalscamp.com/wp-content/uploads/2011/11/Florida-Manatee.jpg

Manatees are large aquatic mammals found in warm coastal waters including tidal rivers and estuaries.  Often called “sea cows”, manatees are in fact more closely related to elephants than they are to cows.  Being entirely herbivorous, manatees will eat large amounts both saltwater and freshwater plants.  Manatees only have molars, which are used to grind up the plant matter they ingest.  In just one day a manatee may eat up to a tenth of its bodyweight, and they can be quite heavy.  Individuals are typically 8 to 13 feet in length and will weigh 440 to 1,300 pounds.  The average lifespan of manatees in the wild is 40 years.

 

Manatees prefer warm water, and tend to be found in regions where the water temperature is above 68 degrees Fahrenheit.  These gentle and slow-moving creatures will migrate north along the Atlantic coast during the warm summer months and can be found in the coastal waterways near Little St Simons Island throughout the summer.  Manatees spend most of their time resting and eating, but they can be playful as well.  Like all marine mammals, manatees must breathe air at the surface through nostrils, but can remain submerged for up to 15 minutes at a time.

 

Historically, manatees were often hunted for their hides, oil, and bones.  Being gentle and slow-moving made the manatee an easy target for hunters.  Today manatees are an endangered species, and they are protected by law.  Even with protection, manatees still face a number of threats including boat strikes and entanglement in fishing equipment.  On many individuals scars are visible where a wound from a boat has healed.

 

While it may be tempting to pet manatees or give them freshwater to bring them closer, these actions may negatively affect manatees.  Manatees may begin to associate humans or boats with these actions which can put them at higher risk for boat strikes.  If you do happen to have the exciting experience of seeing a manatee, the best thing to do is simply enjoy watching it interact with its natural environment.

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Naturalist Fact: Atlantic bottlenose dolphin

 

Image from TropicalParadise.

Bottlenose dolphins are one of the most easily recognized ocean mammals thanks to their reputation as intelligent and playful creatures. Their long “beak” ends in a perpetual smile and their curious nature often results in interactions with humans. They can be found in warm ocean waters all over the world, limited only by temperature. On Little St. Simons Island, bottlenose dolphins are a common sight in the tidal creeks, where they use echolocation to expertly trap fish caught in the rapidly changing tides.

People commonly use the terms “dolphin” and “porpoise” interchangeably, but there are a few key differences between the two. Most visibly, dolphins tend to have longer beaks than porpoises. It is also easy to identify dolphins when they surface for air since their dorsal fin will appear curved compared to the triangle-shaped dorsal of the porpoise. Dolphins also have cone-shaped teeth while porpoises have spade-shaped teeth.

Image from GulfShores.com

Bottlenose dolphins are extremely social. They form groups called “pods” and communicate frequently using clicks and whistles, most of which are audible to humans. Their powerful tails and slender bodies allow them to travel quickly and jump extremely high—the fastest recorded bottlenose dolphin traveled at 18 miles an hour and the highest jumper reached 16 feet!

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Early Fall on Little St. Simons

September 22nd was the first official day of Fall, and we’re starting to see the effects here on Little St. Simons Island. The Muhlenbergia (also called Muhley grass) is starting to bloom, the Eastern diamondback rattlesnakes are making more appearances along Beach Road, and the shorebirds are starting migrate in large numbers. Just three days ago, we counted 70 American Oystercatchers, 125 Marbled Godwits, and 211 Black Skimmers–all in one group at Sancho Panza!

Another fall staple is the fallow deer rut. The bucks have full antlers now that they use to mark and defend their territory. Just yesterday, we came across a spotted buck who left behind this excellent example of territorial behavior:

Traces of fallow deer rut. Photo from Britt.

You can clearly see where the buck used his antlers to scrape the ground beneath this tree. He then left his urine for scent and marked the tree as well; can you see all the broken branches?

Fall on Little St. Simons Island is a time of stunning floral and faunal changes. We look forward to sharing these with you over the coming weeks, stay tuned!

 

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Bat sampling on Little St. Simons Island

Little St. Simons Island, along with being a secluded retreat and fantastic place to experience nature on the Georgia coast, is also a living laboratory. Throughout the year, we host several wildlife biologists working on a variety of projects.

DNR bat biologist, Trina Morris, shares ANABAT technology with our guests. This handheld device brings the bats' echolocation sounds to a frequency that we can hear.

This spring and summer, University of Georgia graduate student Craig Bland is studying roosting habitat preference of the northern yellow bat (Lasiurus intermedius). The northern yellow bat is a foliage-roosting bat, often concealing itself in Spanish moss during the daylight hours. However, this bat is fairly uncommon and little is known about its natural history.

Craig and his team are fixing miniature radio transmitters to Northern yellow bats caught here on Little St. Simons Island and Sapelo Island just to the north. Then, during the day they locate the bats’ roosting location using radio telemetry. By analyzing the characteristics of the roosting sites, the team hopes to get a better understanding of their habitat needs.

Bronson retrieves a bat from the net stretched across the pool.

Last week Craig, one of his technicians Bronson Curry, and Georgia DNR biologist Trina Morris set up mist nests across the swimming pool. Bats frequent this area in the evenings, chasing insects and swooping down for a drink of water. Just after the sun went down, we began to see bats flitting and darting overhead, most cleverly avoiding the nets. However, the bats began to get tangled in the nets, and by the end of the night, a total of 72 bats had been caught!

 

The northern yellow bat with its band and transmitter, ready to be released.

Out of these 72 bats, only one was a northern yellow bat! The large (second largest bat in Georgia to the Seminole) blonde-haired beauty flew into the net at 11:45 pm. He was successfully equipped with a transmitter and located again this morning just outside of the main compound. All the other bats caught were Seminole bats (Lasiurus seminolus) and evening bats (Nycticeius humeralis).

Before Craig started mist netting for this study, there were only two other documentations of the northern yellow bat on LSSI—one in May 2010 and the second in August 2011. To read more about those sightings and mist netting, check out this previous blog post.

A bat's wing is similar to the human hand with a membrane streched between the fingers and forearm.

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Northern Yellow Bat on Little St. Simons Island

Last month while hosting cocktail hour some of our guests reported an injured bat at the pool.  We went to the pool to look for the bat and found it hanging on the pools’ gate. We watched it fly up into a clump of Spanish moss and at a quick glance- considering its size and coloration, my immediate reaction was “Yellow Bat!”After quickly explaining the significance of potentially finding a Northern Yellow Bat, my very enthusiastic guest companions helped me photograph it. I sent the pictures to Georgia’s Non-Game DNR Bat Biologist, Trina Morris and she confirmed that it was indeed a Yellow Bat! This is a significant find considering that it is only our second documentation of a Yellow Bat on Little St. Simons Island.  The first documentation was in May 2010 when GA Non-Game DNR captured one in a mist net.

Northern Yellow Bat (Lasiurus intermedius) in the Spanish moss. August 2011.

Northern Yellow Bat May 2010

Little is known about Yellow Bats in Georgia and biologists are working to obtain more information. The Yellow Bat is known to use Spanish moss as a roosting location. Biologists believe that their preferred habitat is old growth maritime forest, which has the highest density of Spanish moss, and hope that more data about the species may be gathered by mist netting on LSSI and Georgia’s other barrier islands.  Mist netting is a way to capture bats in an effort to determine local species diversity, population size and health. A large nylon net is raised, usually over a small area of fresh water, using a pulley system on two metal poles. When the bats fly over the water to drink the idea is for them to get entangled in the net. Nets are periodically checked by biologists for bats, when a bat is caught, the net is lowered and the bat is carefully removed. Species, weight, sex, gestational stage (if pregnant or lactating), and an age estimate are some information gathered when bats are in hand. We are looking forward to working more Nongame DNR on surveys and research on the island and hope that through this we are able to learn more about the Northern Yellow Bat in coastal Georgia.

Bats are fascinating and especially valuable in helping to control insect populations. Bats should be given the same respect as other wild animals and should only be handled by professionals. If you find a bat that you believe is injured in your home or yard, please contact a wildlife professional for help. If a seemingly healthy bat finds itself trapped in your home try opening your doors and windows to provide an escape route. Like other wild mammals never pick up a bat. Thank you to the Odea Family who were so helpful in reporting and photographing the Yellow Bat!

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Coyote on Camera

I walked among the Wax Myrtles behind the northernmost beach on Little St. Simon’s Island last Saturday afternoon and collected a trail camera that I have set up on a game trail. The motion detection trail camera captures many of the islands wildlife and is a great tool for detecting and monitoring them. I was ecstatic to find that the camera had captured a picture of the island’s ever illusive coyote! The picture was taken on January 5th at 4:03AM. Coyotes are known for their secretive nature and are primarily nocturnal although they can be active at any time. Coyote’s are fearful of humans and therefore avoid us at all costs; this is a huge part of why they are so difficult to see. They are omnivorous and eat a large variety of plant and animal materials. We have been monitoring this coyote and its effects since May 2010 when the island’s staff first began noticing coyote tracks. The coyote has had little negative effects on the island and we will continue to monitor it closely.

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