FAUNA

Fly Pelican, Fly

We observed great flocks of wading birds flying overhead toward their evening roosts in the Everglades … They appeared in such numbers to actually block out the light from the sun for some time. —John James Audubon

People have always associated the Everglades with long-legged birds. Storks, egrets, pelicans, and herons generally symbolize the essence of this unique ecosystem. Indeed, the wet, warm environment has long since attracted thousands of birds from all over the tropics and the North American continent.23 Although many species of birds once inhabited the coastlines, marshes, and swamps of South Florida, their numbers have been greatly reduced. Today, over 350 different species of birds reside within the Everglades territory, and about 200 are migratory birds.23

Though there are many different ways to identify one group of birds from another, the birds of the Everglades can be generally categorized by three distinct types: wading birds, land birds, and birds of prey. 81 Each type has unique food preferences, mating rituals, and so on. They range in size from considerably large—like the great blue heron that can get as long as 55 inches from head to tail and as heavy as 8 pounds—to the very tiny, as in the case of the Everglades sparrow, which is not much bigger than a small mouse.24 Bird migrations are directly tied to water levels; low water levels attract a large variety of wading birds, as well as their predators.73

Wading Birds

Wading birds are the most commonly seen birds in the Everglades. They are usually found near abundant water sources, and they are stealthy hunters that mostly live on aquatic prey. Wading birds are categorized by their long and lanky legs, which they use to wade into the water to catch their food—hence the term “wading birds.” Birds belonging to this group include several different species of herons, storks, and egrets. Others such as the glossy ibis, white ibis, least bittern, and Roseate spoonbill also belong to this group.

The seasons play a major role in mating, nesting, and feeding. Nesting typically coincides with the dry season. The dry season is also a particularly good time of the year for hunting, because fish and aquatic prey are more exposed in lower levels of water. Wading birds are also known to travel long distances; the longest recorded flight is said to be 7,100 miles in nine days.24

Wading birds such as the American wood stork have experienced population drop-offs in recent times, with loss of habitat being the main cause. Thanks to modern restoration efforts, wading birds are making significant recoveries. In December 2012, the US Fish and Wildlife Service announced it planned to upgrade the wood stork’s status, moving it from endangered to threatened.72

Great Blue Heron

The great blue heron is the largest heron of North America. It has a wingspan measuring up to 79 inches and a stride measuring up to 22 centimeters.24 Great blue herons are mostly known for their long, rusty-grey necks and beautiful arrangement of feathers, which attracted many commercial hunters to the Everglades during the 1800s. The great blue herons’ natural range extends from Canada to Mexico and has been seen in many far-off places such as Central America, South America, and Africa.

Great blue herons primarily feed on fish, but they are also known to snack on small mammals, reptiles, amphibians, and birds. They are opportunistic hunters that typically swallow their food whole. Great blue herons often breed in colonies alongside other species of herons. These colonies can get quite large, sometimes ranging up to 5,000 nests per colony.24 After eggs incubate and hatch, both parents feed their young at the nest by regurgitating food. Parent birds have been shown to consume up to four times as much food when they are feeding young chicks than when laying or incubating eggs.24

Commercial hunters relied on annual migratory nesting cycles.27 Adults birds were slain for their plume, while young nesting birds were left to die in their nests. When the Migratory Bird Treaty Act of 1918 was passed, the interstate shipment of migratory birds became prohibited.

American White Ibis

The American white ibis is a regular to South Florida. Besides inhabiting the wetlands, the white ibis also makes a happy living alongside people in many populated areas of South Florida. They are often spotted around town walking through a puddle after a heavy rainstorm. White ibis are regular visitors to shopping plazas, parking lots, and residential neighborhoods alike.

Its bright red beak and white-feathered body makes it distinguishable from other birds. They are not very large: an adult bird may grow up to 26 inches and weigh 2 pounds.27 This particular species of wading bird belongs to the family of ibis, Threskiornithidae. Like other wading birds, their diet consists of aquatic organisms such as insects and small fish. Their breeding range spans along the Gulf Coast, Atlantic Coast, and the eastern coast of Mexico and Central America.24 The American white ibis has been known to interbreed with scarlet ibis, however this only occurs in areas where the two species overlap.

To increase reproductive success, a male white ibis will engage in multiple extra-pair copulations, whereas the female remains monogamous. Male birds have also been known to pirate food away from females and young juveniles during breeding season.28 Studies show that pollution affects hormone levels in males and females, causing a disruption in mating behavior and resulting in lower reproduction rates among white ibis colonies.

Land Birds and Birds of Prey

In contrast to wading birds, land birds and birds of prey do fairly well in dry habitats. Several types of birds of prey are also regular visitors to wet areas, such as coastlines, cypress swamps, and mangrove islands. Climatic variables also dictate the migratory patterns of land birds and birds of prey. Many species of land birds migrate to the Everglades on a seasonal basis, especially during the winter months. One of the most well-known groups of migratory land birds is the warblers, who were given this name because of their beautiful signing. Land birds such as cardinals, blue jays, meadowlarks, crows, and woodpeckers make the Everglades a permanent residence.

The term “birds of prey” is often used to describe birds that use a hooked beak or claw to catch their food.30 Birds of prey such as hawks, eagles, owls, falcons, and kites reside in many parts of South Florida. The southern bald eagle and snail kite have reached critically low numbers. It is estimated that 1,100 pairs of nesting southern bald eagles exist within the Everglades territory.31 Like various wading bird populations, the snail kite’s natural feeding conditions have been disturbed by humans. The snail kite does not have a varied diet and feeds exclusively on apple snail. Due to improper flooding, the apple snail population has decreased, thus limiting the food source of this extraordinary bird.

Red-Shouldered Hawk

Red-shouldered hawks are at the top of their food web; they don’t have many predators. Red-shouldered hawks can be found sporadically throughout North America, but they make a comfortable home in the highlands of the Everglades. The red-shouldered hawk is a medium-sized hawk, and size is its only disadvantage over larger birds of prey. Female red-shouldered hawks are slightly larger than males; adults are usually between 10 and 24 inches in length and weigh about 25 ounces.24 Their long tails are marked with narrow bright lines, and the red shoulders that give them the name are only visible when the bird is in a perched position.32

Red-shouldered hawks will prey on small mammals, reptiles, amphibians, and large insects, and they have been known to devour small birds. During the breeding season, the female bird will lay between 3 to 4 eggs. Pairing red-shouldered hawks tend to be on full alert at this time, because their incubating eggs are always in danger of predators. Even adolescent red-shouldered hawks remain aware of their immediate surroundings, because they too can make a nice meal for the occasional barred owl in the area.

American Black Vulture

Whenever there is a foul, dead smell in the air, you can be sure a black vulture isn’t too far away. This bird of prey is fairly unpleasant to look at because it is covered in black colorless feathers and a grayish featherless head, and it is revered for its distasteful association with terrible odors. However, it is a vital piece to the native ecosystem. The black vulture’s important ecological role is the disposal of carcasses.

The black vulture is a scavenger that makes a living in the prairies, wetlands, and swamps of South Florida, but their extended range is widespread. They are found all over the southern United States, and down to the southern tip of the Andes Mountains. Black vultures are relatively large for a bird of prey. They have wingspans of 5 feet, measure between 22 to 27 inches in length, and they weigh between 4 and 6 pounds. 24

Black vultures typically stay put; very seldom will a flock migrate. The black vultures of South Florida make the Everglades a permanent home. Their breeding season starts in January and will last until the early fall season. Both parents incubate the eggs, which hatch after 21 to 48 days.24 Chicks are fed in very much the same as other birds, by regurgitating food at the nest site.

King of the Everglades

Charles Darwin once wrote, “In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.”33 American alligators have developed many adaptations that make them very well suited for the wetland environments of South Florida, making them the dominant predator in the entire region.74 Their populations have reached approximately 1 million in Florida.34

In the Everglades, the American alligator plays a central role because it affects the existence of other organisms in key ways.38 The alligator has been given the label of apex predator, defined by the top predator in an ecosystem. Known as the king of the Everglades, the American alligator is the biggest, most ferocious gator on the planet, having the strongest laboratory measured bite of any living creature in the animal kingdom.39 Gators can grow up to 11 feet in length and weigh up to 800 pounds; the largest ever-recorded alligator was reported to be a whopping 19 feet and 2,200 pounds.40 Once an alligator reaches adulthood, it will consume just about anything. Any animal is a potential target to the American alligator. One should always remain vigilant around water sources when visiting the Everglades.

American alligators spread further north than their crocodilian cousin, the American crocodile. The alligator is more equipped to deal with colder temperatures than crocodiles. This particular variety of alligator will sometimes venture into brackish waters.41 Like their 150-million-year-old reptile ancestors, modern alligators have predominantly large tails used for aquatic propulsion and self-defense; the tail itself accounts for half its body length. For the American alligator, breeding begins in the spring. A female alligator will lay between twenty and fifty eggs. Half of those will survive the first year, if she is lucky.

American Crocodile

The anatomy of an American crocodile is not much different from the American alligator. The most obvious difference between a crocodile and an alligator lies in the lining of teeth and snout. The crocodile has a longer, narrower snout. Crocodiles also have lighter pigmentation, which plays to their advantage because they too rely on camouflage to surprise their prey.

American crocodiles are tolerant of saltwater. They make a home around the mangrove islands of South Florida. Like the alligator, the American crocodile will prey on just about any animal; birds, mammals, amphibians, reptiles, and fish being the preferred items on the American crocodile diet. The crocodile is also very important to the ecosystem; its waste provides vital nutrients for smaller animals in the food chain.42 Although the alligator got the name king of the Everglades, the American crocodile is capable of growing much larger. On average, mature males can grow up to 16 feet in length.77 Water pollution and loss of habitat have caused their populations to drop to a little more than 2,000.43 Restoration efforts are currently underway to revive their dwindled numbers.

Snakes, Snakes, and More Snakes

Snakes are a very important piece to any ecosystem. In South Florida, they help keep the rodent populations under control. In addition, because many Florida snakes will feed on others snakes, they also help balance the number of out-of-control snake populations. Due to loss of habitat, many native snakes have been driven out of their natural settings and into residential areas in search food and shelter. Many snake bites occur right in our own backyards. Of the 24 different species of snakes in the Everglades, 4 are regarded as venomous; including the coral snake, Florida cottonmouth, pigmy rattlesnake, and eastern diamond rattlesnake.44 In the event a person should come into contact with one of these venomous serpents, extreme precaution should be taken.

The coral snake prefers wooded areas, particularly tropical hardwood hammocks. They are known for their red, yellow, white, and black colored banding, and they are often mistaken for kingsnakes. The cottonmouth is of the semi-aquatic variety, but it may be found in dry habitats as well. Adult cottonmouths can exceed 31 inches in length. The pigmy rattlesnake is much smaller by comparison, having an average length of 54 centimeters. Although pigmy rattlesnakes do not produce enough venom to inflict serious harm to humans, they have been known to hold their ground when confronted; according to the Florida Reptile Institute, 28 people were bitten by this species in Florida between 1935 and 1937, with no deaths reported.76 The eastern diamond rattlesnake is the most toxic snake of them all. It is also the largest rattlesnake ever known, capable of growing up to 8 feet in length. Eastern diamond rattlesnakes usually feast on rodents, marsh rabbit, and quail. If you stumble upon a diamondback, keep a good distance—they can strike at twice their body length. Plus, the mortality rate for untreated bites is greater than 75 percent.75

Mammals

Mammals are generally categorized by live births, a skin producing hair or fur, and the ability to nourish younglings with milk. Approximately 40 different species of mammals inhabit the South Florida wilderness, including rodents, rabbit, fox, felines, and bear.46 Many native mammals have adapted characteristics that favor semi-aquatic environments. Marsh rabbits, river otters, and Everglades minks are examples of mammals that do very well in marshes and swamps. Marine mammals like dolphins and manatee occur frequently along the coast. Raccoons and opossums are common creatures to most habitats in South Florida.46

Florida Black Bear

The Florida black bear is the largest land mammal in all of Florida. They can weigh up to 500 pounds and get as large as 6 feet in length.49 Females are generally smaller than males. Florida black bears are solitary creatures that flee at the first sign of confrontation, but females will attack an intruder if she feels a threat to her cubs. They can smell a human from many miles away. Prior to modern development, the Florida black bear occupied much of the peninsula; early accounts had the black bear residing as far south as Key Largo.

Florida black bears usually wander areas of forested wetlands. These large omnivores will generally feed on seeds, shoots, and other native vegetation, but they will also eat meat when the opportunity presents itself. The biggest threat to the Florida black bear is road kills. It is important to note that the Florida black bear is the only known species of bear to occur in subtropical regions. This is yet another example of what makes Florida’s Everglades such a unique place.

White-Tailed Deer

There are dozens of white-tailed deer variations throughout the Americas. The two native subspecies are best identified by their scientific names, Odocoileus virginianus seminolus and Odocoileus virginianus clavium. Odocoileus virginianus seminolus are found in forested wetlands and open marsh prairies. Odocoileus virginianus seminolus is an essential staple to the diet of one important Florida predator: the Florida panther. Bobcats will occasionally attack adult white-tailed deer, as recent studies have shown, but this is somewhat rare. Bobcats usually attack fawn rather than an adult deer.

White-tailed deer eat large varieties of plant food, including fruits, grass, and shoots. Male white-tailed deer, also known as bucks, will spar other males for dominance and the right to breed. Their breeding season occurs between May and June, typically giving birth to a liter of 1 to 3 fawns.50

Elusive Cats

The Florida panther once roamed much of the southeastern United States. They are now exclusive to South Florida and the Everglades—a single wild population of 100 to 160 adult panthers is all that remains.55 That’s a significant improvement in comparison to their numbers prior to 1995, when their population fell between 20 to 30 panthers.55 Low genetic variability had unfavorable results: interbreeding, poor health, and a decline in reproductive rates contributed to population drop-offs. Recently, a genetic restoration program that involved introducing several female Texas cougars was successful in tripling their numbers in only ten years’ time.55 Road kills continues to be a problem for Florida panthers.

Florida panthers are secretive animals and are rarely ever seen in the wild. Male Florida panthers average 130 pounds and measure 6 to 8 feet from head to tail; they have a shoulder height of 2 feet and a front pad width greater than 2 inches. Males fiercely defend their territory, which ranges up to 200 square miles that overlap ranges of several females. The average lifespan of a Florida panther is ten years, once they reach adulthood.78 The Florida panther will prey on squirrel, deer, hog, small gator, and more. To date, there are no recorded incidents of an attack of a Florida panther on a human.

Smaller Mammals

Raccoons and opossums are common creatures to most habitats in South Florida.46 These night-dwelling omnivores will eat turtle eggs, fish, fruit, baby gators, and small birds. Raccoons usually live near water. They are exceptional swimmers that hunt alongside the water’s edge, and they will occasionally get taken in by a gator. The opossum is the lone marsupial of the Everglades. As a typical marsupial does, the opossum carries its infants in a pouch.51 Opossums are shy, solitary creatures, and they are known for their involuntary “play dead” response to a threat. During this act, the opossum will draw back its lips and foam around the mouth while rolling back its eyes.52 A foul smell from its anal glands also confuses predators.
Here are some other mammals worth mentioning.

Grey Fox—A great climber. They usually occur in tropical hardwood hammocks.

Marsh Rabbit—This rabbit has adapted the ability to swim. It makes a home in fresh water marshes and coastal prairies.

River Otter—This semi-aquatic mammal is found throughout the waterways of South Florida. They are especially susceptible to environmental pollutions.53

Fox Squirrel—The largest species of tree squirrel in North America. Fox squirrels are impressive jumpers, being able to leap up to 15 feet at a time. 54

Other Groups

Both fish and amphibians are very important pieces to the native ecosystem. Nearly 300 different species of fish occur in the freshwater marshes and marine coastline of South Florida.56 Freshwater fish populations depend heavily on fluctuating water levels brought on by seasonal variables. The recent introduction of exotic fish to South Florida water supplies has put a strain on native fish populations. Exotic species of fish are fierce competitors.
The Everglades serve as the perfect habitat for a number of amphibious species, including southern toads, pig frogs, Florida cricket frogs, and green treefrogs.79 Amphibians routinely serenade the landscape with a loud and unusual chorus.79 They can be found on trees, hallow tree barks, ponds, marshes—anywhere and everywhere, it seems.

The smallest critters of all, namely insects, dominate South Florida by sheer numbers. The Everglades are home to a large variety of fascinating aquatic, semi-aquatic, and terrestrial insects that are capable of flying, swimming, or burrowing; including butterflies, dragonflies, moths, arachnids, grasshoppers, ants, mosquitoes, and many more. Butterflies are the most diverse among native insects; over 90 species of butterfly have been identified in South Florida.57 Admittedly so, I have a special admiration for these tiny creatures. Many of our native butterflies are covered in beautifully decorative patterns that blend well to their immediate environments.

Citations and References