Sea Turtles

May is when the sea turtles start nesting on Cumberland Island. At the end of the month, forty three nests had already been located. By the end of the summer there will be approximately two hundred nests on the beach if it is a normal year. These are loggerhead turtles that average two to three hundred pounds. They prefer the upper beach and foredunes as nesting sights; most of them will come ashore on the last hour of an incoming tide so they won’t have to crawl a long way to a suitable location; also, more turtles nest on moon lit nights when they can see the silhouette of the shorline.

Female turtles will dig a deep round hole with their back flippers and deposit anywhere from fifty to over one hundred and fifty eggs in the cavity. After covering the nest with sand the mother turtle returns to the sea and the eggs are left alone to hatch which takes about sixty days of incubation time. The sex of the young will be determined by the temperatures in the nest. For example: warmer nests in the high 80’s will produce mostly males.

Turtle nests are targets for predators. On Cumberland, raccoons, feral hogs and ghost crabs would all like to feed on the nutrient rich eggs. The National Park Service conducts a turtle research program that locates and covers nests with wire cages that will usually keep out raccoons and hogs. Crabs however are harder to guard against. After a nest hatches the baby turtles dig their way to the surfact and easily crawl through the protective wire cages to the open beach. Predation on young turtles from the beach to the open sea is heavy as they try to reach the large floating rafts of sargassum weed that can be hundreds of miles from shore in an area known as the Sargasso Sea. If a young turtle can make it that far it has a much better chance of survival as sargassum weed provides plenty of hiding areas from large predators. Once a sea turtle gains some size there is less chance of it becoming a meal for another sea animal. However, Loggerhead turtles develop slowly, at least they keep their close association with the protective Sargassum for up to ten or twelve years; it’s sometime between twenty and thirty years when Loggerheads become sexually mature. At this point in their lives they will return to the beaches where they were hatched; this time to nest themselves and repeat a process that has been occurring on wild beaches around the world for over 150 million years. In recent times though sea turtles have become threatened and endangered by man; a relative new comer with high impact on ocean eco-systems. Sea turtles now face a gauntlet of entanglement devices put into the sea by man such as nets and fish line. Plastic bags floating in the water also kill turtles as they mistake them for jellyfish; a favorite food source. Biological and chemical toxins from polluted waters have a damaging effect on turtles as well as other marine species.
Probably the single largest threat to sea turtles alone is the loss of suitable nesting habitat. These ancient reptiles evolved on wild undisturbed beaches; more and more of these areas now are becoming obstructed with human development; much of which is not compatible with sea tutle nesting activity. Cumberland Island however still has over seventeen miles of wild beach available to nesting turtles. This, along with help from the turtle research team is a positive development in favor of these endangered animals.

Pine Forest

While exploring Cumberland Island many people are surprised to find pine trees in what is otherwise a hardwood forest. It’s not so much the pines themselves but how they are distributed that is a bit confusing. On Cumberland the live oaks are the dominant trees because they can withstand more wind and salt than other competing species, although there are places away from the salt spray zone that can support many other types of trees. By the mid 1800’s some of these areas had been cleared for agriculture. After the plantation era however farm fields were abandoned and eventually regenerated new forest growth. Under these conditions in this region the first trees to become established naturally are the pines; there is also a plot of planted pines on Cumberland.

Pine trees grow faster and require more sunlight than most hardwood trees. Pines have also evolved with a unique way to compete with hardwoods and that is their bark is more fire and heat resistant. If a normal ground fire burns the forest it doesn’t damage the pines but can destroy young broad leaf hardwoods that would eventually shade out future pine seedlings. Of course; if a fire is abnormally hot due to excessive burnable material; the pines can be killed as well.

There are four species of southern pines on Cumberland Island that promote natural fire on the Island. Standing straight and tall these trees make near perfect targets for lightning the main ignition source for forest fires. The distinctive scarring lightning makes on pines can be found on a number of trees around the Island. Pine trees that are hit almost always die but if a fire is started it will certainly benefit the other pines.

So the distribution of pine trees on Cumberland is the result of what man has done here historically and what has occurred here naturally. Over time without human intervention a more natural balance of plant species will develop on the Island and the pines will certainly be a part of it as long as fires are allowed to burn.

The Need for Fire

I was going to wait until June to report on fire; that’s when big thunderstorms develop in the area and produce lightning; the main ignition source for forest fires on the Island. But by mid May we have already had a lightning fire that has burned over two hundred acres; it seems like summer comes earlier than it used to.

Fire is a broad and complex subject, but there are a few things I would like to point out: if you take a walk through our southern forest the living things you see; all plants and animals either directly or indirectly need fire. Wild fires over time have shaped the evolutionary paths of many life forms probably more than we realize. As such; fire is now necessary to maintain the health of our wild-lands. To be more specific; fire is the natural cleansing and re-fertilization agent of the forest. Fire removes dead plant material, opening up the ground to sunlight so new growth can take place. Burning also controls parasites and diseases that can harm both plants and animals. Ash created from fire is like fertilizer on the ground that ultimately benefits future generations of wildlife. This is a process that has worked itself out over time but problems do occur when man gets involved.

Fire ecologists tell us that before Europeans settled North American wild land fires were a lot more common because no one put them out. The native Americans actually started their own fires to control insects and add fertility to the soil in order to grow food. As the new Americans spread out over the continent however fire became more and more of an inconvenience: homes were at risk from burning and forestry practices that placed a dollar value on trees alone took control. The hysteria over fire reached its peak during the first half of the 1900’s when hardly any wildfires were allowed to burn and large campaigns to prevent forest fires were initiated: most of us remember Smokey the Bear; all the while burnable material (fuel) was stacking up on the ground nearly everywhere creating a huge fire hazard and harboring an increasing number of insect pests as well as restricting new growth. After the catastrophic fires that followed, people started to realize the problems with fire suppression and that the native Americans probably had it right all along. At least; frequent small fires were much better than infrequent larger ones; the way our wild-lands originally evolved. In the last couple decades, fire management has come a long way with control burning programs to reduce excessive fuel loads. On Cumberland however, two thirds of the Island lie within a designated Wilderness area that restricts control burns but requires natural fires be left alone. This becomes problematic because under certain conditions, the huge fuel loads on the Island now, could quickly create a catastrophic fire that would possibly burn too much of the Island at once and in the precess destroy much of the wildlife and old growth trees as well as some of the historical buildings. But fact remains; the Island still needs to burn or eventually it will breakdown biologically. The National Park Service which is responsible for Cumberland’s fire management is aware of these and other issues, but forced with budget constraints and politics from several different directions the agency has a daunting task in managing fire. But we have just had a two hundred acre fire with favorable results. There are roughly another twelve thousand acres that need to burn at some point in time, mostly sooner than later. It is still early in the fire season so hopefully we will get another significant burn on Cumberland in the not too distant future.

A Serpent in the Garden of Eden

SNAKE! Just the word can strike fear into the minds of those who are not familiar with these reptiles. Some psychologists believe people have a natural fear of snakes stemming from an earlier period in human evolution when our humanoid ancestors lived on the ground and had to frequently deal with venomous snakes. Whatever the reason, snakes have been feared and therefore maligned throughout at least recorded history from Biblical times to present day culture, resulting in greatly exaggerated tales that have added to the fear factor. As a result; many of these important animals have been needlessly destroyed over the centuries. In reality snakes have actually benefited mankind over time by helping to control rodent populations that can carry deadly diseases and also destroy agricultural crops. I’ve often thought if there was a choice between worrying about a dreaded disease out there I couldn’t see or where I put my feet when walking through the woods, I would opt for the latter.

On Cumberland Island eighteen species of snakes have been identified; three of these are venomous members of the pit viper family. The Eastern Diamondback rattlesnake is the largest. The record length for this beautifully marked reptile is over nine and a half feet although this specimen was not found on Cumberland. Fortunately, Diamondbacks are among the least aggressive venomous snakes on the planet and they try to avoid humans if possible while helping to keep the rodent population under control. The Canebrake rattlesnake is common on the nearby mainland but seldom found on Cumberland. Occasionally a Canebrake will enter a coastal creek and be carried to the Island by the tides; it’s unlikely there is a breeding population of these snakes on Cumberland. The Cottonmouth or Water Moccasin is our other pit viper and like the Diamondback is well established on the Island but tends to stay in or close to freshwater areas. More than the others, I find people fear the Cottonmouth. The story is this snake is aggressive and will come after you. Well, after spending nearly a lifetime in the woods and swamps of this region I have never experienced this and I’ve encountered hundreds of these snakes over the years. However, they will like other animals defend themselves; they do this by coiling up, putting their heads back and opening their mouths exposing the cotton white interior. At this point, usually the intruder gets the idea of what might be next even though the striking accuracy of this snake is not very good compared to its cousin the Diamondback.

On Cumberland we have relatively few snake sightings and most of these are of the harmless Black Racers that are more likely to be seen on the roads. The Black Racer is one of our snakes that will feed on other snakes: the Eastern King snake is another. There are a number of other snake predators on the Island such as hawks, owls and alligators.

Snakes however are survivors that have made many adaptations to cope with the various habitats they live in. The constrictors on Cumberland; snakes that kill prey by tightly coiling themselves around their victims; are also excellent tree climbers. Species such as both Yellow and Red Rat snakes can hunt the tree branches for squirrels and birds as well as seek out hollow tree cavities for their own safety.

Down through time snakes have been feared and demonized yet they are an important part of many functioning natural systems that have numerous benefits for mankind. With this in mind, the thought of a serpent in a perceived Garden of Eden is not such a bad thing.

A Touch of Mink

Many people who visit Cumberland are surprised to learn there are mink on the Island. Most of our guest’s associate this member of the weasel family with more northern locals. Mink actually range all the way down to South Florida where an endangered sub-species known as the Everglades Mink still manages to survive. Throughout other parts of the south however the mink is not considered endangered but it’s an animal seldom seen by humans other than duck hunters or fishermen that spend a lot of time in this secretive animal’s wetlands habitat. Mose people though, have heard of mink due to the fact this animal’s beautiful fur has been used for years to make high dollar garments such as mink coats. Today captive, farm raised mink have taken over a large part of this market: one reason is fur coloration can be kept more uniform with ranched animals. On Cumberland I have noticed fur coloration can vary greatly among our wild mink from dark brown to a rusty red and even orange. Recently I was with a group of people as we watched a blond two foot long specimen work its way down the river bank on the west side of the Island. It was the first time I’ve ever seen this color phase.

Mink seem to be constantly on the move; either searching for food and mates or trying to avoid becoming food themselves. There are a number of predators that will feed on these small animals; hawks, owls and bobcats would all dine on a meal of mink. But alligators are probably their main threat in our area. Stomach samples taken from local alligators indicate they frequently take mink. The mink itself though is a formidable predator for an animal it’s size: birds, rodents, fish and small crabs are all part of their diet. Mink cover large territories and many use several denning sites along the way, complicating the efforts of anyone who is trying to observe these illusive animals.

On our Cumberland outings we talk a lot about the Island’s wildlife. If we can get a glimpse of a seldom seen species it can be a memorable experience for some people and a touch of mink always helps.

The Essential Marsh Hen

While Cumberland Island ‘Greens Up’ in April, so does the nearly 8,000 acres of adjoining Salt marsh. This is also the month when the bird most associated with these wetlands begins nesting. Clapper Rails also known as Marsh Hens are a true symbol of the Salt marsh because this is the only habitat they live in; if you study the bird it’s easy to see why. Rails are laterally thin birds which allows them to move about freely through the thick grasses of the marsh. Their large feet help them swim and provide support on soft wet ground, while the bird’s long curved bill allows it to probe this muddy environment for it’s main food source, fiddler crabs and snails.

Clapper Rail nests have been described in bird books as grass made platforms on the ground. However, the one nest I observed was a loosely woven grass bowl in a thick clump of new growth Saltmarsh cord grass about one foot above the ground. Because this was new spring growth, the nest had been lifted another six to eight inches above the ground by the time the ten buff colored speckled eggs hatched. Young rails have dark fuzzy feathers and are able to leave the nest and feed themselves within a day or two of hatching. Although they are tiny and frail looking, the chicks quickly adapt to life in a landscape that floods twice every twenty-four hours with high tides.

Rails tend to be secretive birds and spend most of their lives hidden in the tall grasses of their environment. However, they are often seen in early mornings at low tide bathing and feeding along the shore of saltmarsh creeks that border Cumberland. This time of year as the marsh turns green again and life is being restored there, it’s good to know the hardy little Marsh Hen is an essential part of it.

Fiddler on the Marsh

“Are those bugs all over the ground?” This is a question I often get when our Island outings pass by a Saltmarsh. What people are referring to are the great numbers of small fiddler crabs that live in this biologically rich environment. There are at least three species of fiddlers that inhabit Cumberland’s Saltwater Wetlands. As the name implies, this crab has a kinship with the fiddle as the large single claw of the male crabs in a way resembles that instrument. During the warmer months when fiddlers are active, male crabs can be seen waving this pronounced claw in the air in an effort to attract females for breeding and to keep other males out of their territory. Fiddlers feed mainly on detritus, a mixture of decomposed organic material, mostly grasses produced in the marshes. These prolific crabs have specialized mouth parts that can seperate the organic food they ingest from the mineral sand, which is spit out in the form of small round pellets. This feeding behavior qualifies the fiddler as a slow land builder. Over the years I have come to realize these little crabs play a big roll in the ebb and flow of the Saltmarsh Eco-system. For example: many animals eat fiddlers. Along with several species of wading birds, mammals such as mink and raccoons feed heavily on this abundant food source at low tide, when the muddy ground in the marsh becomes exposed. During periods of high tide, several species of fish as well as the much larger blue crabs eat fiddlers. So fiddlers fill a niche here between detritus and numerous predators.

Fiddler crabs most likely to be seen along the edge of a Saltmarsh are the colorful Sand fiddlers also known as Chinabacks: so named because of the intricate designs on their shells that look like painted porcelain china. As these roughly one inch long crabs gather along the Saltmarsh shoreline they are easy to see and sometimes mistaken for “bugs” by visitors to the Island. However these tiny crabs spend much of their lives burrowed in the mud. During the colder months when fiddlers are less active they are safer underground. But as temperatures rise this time of year we see the fiddler on the Marsh.

Painted Bunting

April is the month when the Islands most colorful bird makes its first appearance after a migration from the West Indies and Central America. Painted Buntings arrive to begin nesting on Cumberland. As in most bird species, male buntings are the ones with the most distinctive plumage. Biologists believe this is to direct predators away from the females as well as to attract the females to the most colorful males. Whatever the reason, male Painted Buntings are well named with their bright red, blue, yellow and green plumage; while the females are completely green. These birds are only about five and a half inches long but so brightly colored they always grab the attention of those who see them. Unfortunately bunting populations have been decreasing at a rate of about three percent each year. This is mainly due to the fact they are losing nesting habitat in large areas of their Spring and Summer range on the coast of Florida; areas that have been heavily developed. On Cumberland however there is still suitable habitat for these beautiful birds, especially in the thicker edge vegetation between forest and wetlands. This is the type of habitat found around the Greyfield Inn and also nearby Dungeness area; it’s the reason why many species of song birds including buntings are often seen here.

Although Cumberland lies within the Southern temperate climate zone there is a strong sub-tropical influence here and the return of the bunting in spring serve as a reminder of this fact.

The Alligator

Spring is officially here and so are warmer temperatures needed to bring out the reptiles. Cumberland is home to over forty species of reptiles, the largest and most noteable being the alligator. This is the breeding season for these top predators so the bellowing roars they make to locate mates will be heard in the freshwater wetlands on the Island. Alligators are freshwater animals that will venture into saltwater to feed. During the warmer months they are seen in the saltmarsh and tidal creeks on the west side of the Island. Some alligators on the north end of Cumberland have been known to enter the ocean at night to feed on large schools of mullet that gather there during the summer months. But alligators cannot live in a salty environment full time because salt will eventually dehydrate them so they have to make it back to freshwater in order to survive.

As one might expect, we get a lot of questions about these high profile animals such as “How big do they get?” The largest alligator on record is a 19’2″ animal found in Lousiana.

On Cumberland a twelve foot alligator would be considered a very large specimen. Under ideal conditions of food and climate, young alligators grow about one foot a year until they reach six feet, then the lengthening process slows down as the animal grows thicker. The males grow faster than females; in twenty years a male can reach a length of about eleven and a half feet, while a female would only grow to a little over eight feet during that period. However, both become sexually mature when they are about six feet long.

An alligator nest consists of a large pile of dead vegetation close to water. In this mound the female can lay anywhere from 20 to over 50 eggs. The incubation period is about 65 days and the temperature of the eggs in the nest will determine the sex of the young. Eggs below 86 degrees will hatch all females while eggs above 93 degrees will be all males. Temperatures between these two extremes will produce both males and females but mostly females. This information came from studies of alligators mostly in Florida.

Female alligators are good mothers and are very protective of their nest and young. The young may stay close to her for up to three years before leaving to find their own new territories. On Cumberland, once an alligator reaches a length of three feet they have nothing to fear except a larger alligator. The big ones will eat the smaller ones, especially during times of drought when their normal food supply has been interrupted.

Truly wild alligators shy away from humans but can become aggresive and dangerous if people are feeding them. Recent alligator attacks in Florida involved these types of habitual animals. On Cumberland there has been one recorded alligator attack. In 1989 a man bathing in a freshwater pond was bitten by a six foot alligator that quickly released him after making contact. However, Island alligators are known to feed on large mammals such as deer, feral hogs and possibly feral horses so a human in the water cound be mistaken for something else.

The alligator is certainly at the top of the food chain in this region and the undisputed king of the freshwater wetlands. As such, they have an important niche to fill in order to keep this natural system in balance. Alligators only feed on other animals many of which are mammals that can over populate. Without predation, diseases will impact and weaken prey species. So the alligator helps to level the boom and buse cycles of these animals creating a more disease free healthier environment.

Alligators are also important in other ways. I have found that many people are fascinated by these animals; whether they be seasoned gator hunters from Florida or tourists from Europe or a northern city in this country. The fact there are large predators in the wild like the alligator that can overpower and kill a human, has a humbling effect on people. As a result, many of our guests want to see and learn more about these great reptiles. Now with the warmer Spring temperatures, alligators are becoming active again on Cumberland Island.

Live Oak Trees on Cumberland Island

It’s Spring green-up time on the Island as new leaves and blooming plants are evident everywhere. Cumberland is located in the Southern temperate zone but because of the warming effects of the ocean, many sub-tropical plants thrive here including the Island’s most notable tree, the Live Oak. Although in the same genus as other oaks, Live Oaks are considered to be evergreens. Unlike most other hardwood trees, they do not drop their leaves in Autumn and lay barren over the Winter months. Instead, Live Oaks lose most of their leaves in the Spring at the same time the new leaves and pollen heads are forming.

Live Oaks are the dominant trees on the Island because they can withstand more wind and salt spray than other competing trees. The horizontal limb growth forms a broad sprawling canopy while the shallow root system spreads out to cover the same distance underground. This combination works well to stabilize the tree.

These sturdy trees with hardwood and twisted grains were the first important commodity to be harvested on the Island. In the early 1800’s Live Oak limbs with their natural curves were used for the main structural parts of the old sailing ships.

Live Oaks have an average life span of about 300 years although there are specimens in some areas that are much older. On Cumberland most of the original trees the early settlers found are now gone. But a few still remain. One tree on the Greyfield Inn property has a circumference of twenty-nine feet, and according to researchers from the University of Georgia, is about 350 years old.

Compared to other oaks, Live Oaks are fast growers, so a mature forest of these majestic trees once again covers the Island and Spring is the time when they really stand out with their new bright green leaves.