An alligator glides across the still waters in the Everglades. Another basks on the water's edge. Swoosh! A young gator futilely lunges at an ibis. In this subtropical habitat, the sleek creatures surface everywhere.

Zoos are great, but nothing beats watching tropical critters in their natural environs. Nowhere else in the United States but Everglades National Park can travelers see more than 300 species of birds, explore sawgrass prairies, hardwood hammocks and mangrove forests in one place, and observe wild alligators up close.

The Everglades is a sheet of fresh water, six inches deep and 50 miles wide, that flows south from Lake Okeechobee near Orlando into Florida Bay. Within this ecosystem, Everglades National Park encompasses 1.5 million acres. Roughly twice the size of Rhode Island, the park provides a protected habitat for alligators, crocodiles, nesting birds, rare plants and hundreds of other species.

Visitors can pitch tents in campgrounds, sleep in houseboats or stay in a lodge. I opt for soft adventure — an air–conditioned room with a double bed and hot shower at the Flamingo Lodge, Marina & Outpost Resort, located 38 miles southwest of the park's main entrance. Built too many decades ago, the park's only lodge looks tired and worn. But it's clean and provides the essentials.

Waterways and paths lead vacationers into the Everglades' diverse environments. At the marina, tour boats start their journeys down Buttonwood Canal to Coot Bay, a favorite destination for houseboaters and anglers. Mangroves arch their roots above the water like legs poised to step across the canal. Thus their nickname, the walking trees.

As this three-mile waterway cuts through dense forests, it showcases some of the Everglades' most admired creatures. A flock of snowy egrets dapples a mangrove with the sheen of their white feathers. An ibis with distinctive black–tipped wings glides in the blue sky. Along the shore, a gangly wood stork stands still, ready to snatch a fish.

"They're the 'indicator' of the Everglades' health," the guide explains. "A wood stork needs hundreds of pounds of fish. If the number of wood storks is down, we know the park is in trouble."

And that's based on a bird count that is already startlingly low. Due primarily to habitat loss, fewer than 400,000 wading birds annually populate the park compared to one million in the 1940s and an estimated three million when John James Audubon visited southern Florida in the 1830s. Even the feather industry, which at the turn of the 20th century decimated 90 percent of the Everglades' birds, was less devastating than the impact of modern development.

On the return ride, we passengers scramble to the port side of the boat to admire a nine–foot alligator cruising along the edge of the estuary. Half of its length is tail. Round eyes, high eye ridges and broad snouts distinguish alligators from crocodiles, which also reside in the park. In fact, this is the only place in the world where crocodiles and alligators live side by side.

"You'll know a crocodile when you see it," the guide assures us. "Flat eyes, pointed snout and its fourth lower tooth juts outside its jaw."

The Buttonwood Canal dead ends at a plug, a manmade barrier that prevents the salt water of Florida Bay from contaminating the park's estuaries and lakes. A hoist lifts boats, secured in harnesses, from one side of the plug to the other. Averaging only five feet in depth, the bay covers nearly 30 percent of the park. More than 100 small islands dot waters rich with snapper, grouper, flounder, pompano and countless other fish.

Back at the marina, I'm amazed to see an alligator snoozing on the boat ramp. Posted signs admonish visitors to maintain a distance of at least 15 feet, a difficult order to follow when the critter looks so non–threatening and photogenic.

As twilight approaches, mosquitoes buzz ravenously. In the summertime, these insects are so thick and aggressive that only diehard anglers frequent the park. Fortunately, only 13 of the 43 types of mosquito in the park bite humans. The bugs are less pesky in the winter, but visitors armed with insect repellent enjoy themselves more. I escape to the lodge's screened-in pool and patio for pleasant protection from these Everglades irritants.

The following day, I explore the park by land. Several trails off the main road highlight the Everglades ecological diversity. Most are less than half a mile long but their sights can entertain onlookers for hours. Flora ranges from mangroves to sawgrass to pinelands and hardwoods — evidence that life zones in the Everglades are measured in inches of elevation, not thousands of feet.

A few miles west of the park entrance, Taylor Slough courses through sawgrass prairie at Anhinga Trail. While lily pads topped with purple blossoms bob on the slow moving water, willow thickets hug the slough's edge. Perched on a branch, an anhinga spreads its elegant wings to dry. Gold–etched sawgrass rustles in the breeze.

In contrast, the neighboring Gumbo Limbo Trail winds through a dense hammock — an island of tropical hardwood trees only a few feet higher in elevation than the surrounding wetlands. Aerial gardens of epiphytes bedeck royal palms. As it winds around a tree, a strangler fig chokes its host. Bark as red as sunburned skin peels off massive gumbo limbo trunks. When set in the ground as fence posts, branches from these trees take root, creating living fences.

Halfway back to Flamingo, the boardwalk at Pa–Hay–Okee Overlook spans marshy sawgrass dotted with yellow flowers. Hammocks of dwarf cypress trees stud the view with their slender wispy profiles. A huge orange and yellow lubber (grasshopper) inches up a palm leaf.

Interpretive signs identify several of the species, such as the pond apple which alligators and turtles eat. "They're edible," the plaque explains, "but you must enjoy the taste of turpentine."

Sawgrass gives way to mangroves at West Lake. While canoeists ply the waters, I penetrate a forest of walking trees. Have I stepped into a hair salon? The area reeks of permanent wave solution. Actually the odor is hydrogen sulfide gas, a natural by-product of decomposition in waterlogged environments. Tannins excreted from the mangroves' roots have dyed the water a rich reddish brown. If not for the park-maintained boardwalk, the dense thickets would be impenetrable.

Ironically, I encounter the greatest concentration of wildlife at Eco Pond, located only a short walking distance from the lodge. A chorus of bird songs rises from the pond's small island. Snowy egrets bob on branches while white ibis cluster in marsh grass and American coots skim on the water. Sensing a red-shouldered hawk peering down from its lofty perch, brown marsh rabbits hop to cover. Walkers scurry past an alligator dozing alongside the dirt path.

The morning of my departure, I stroll to the marina and plop down on a pier to watch life on Buttonwood Canal unfold. A wood stork feeds along the estuary. Perhaps all is well in the Everglades — at least today.

PERSONAL REFLECTIONS: We were awestruck by the abundance of wildlife co-existing at Eco Pond. White ibis, snowy egrets, American coots and brown marsh rabbits shared the same environment with red-shouldered hawks and alligators.

We were also amazed by how plant communities change from sawgrass prairie to pine flats in mere inches of elevation. In comparison, life zones in our home state of Colorado measure thousands of feet in elevation.

IF YOU EXPLORE EVERGLADES NATIONAL PARK:

The main entrance of Everglades National Park is located 10 miles southwest of Homestead, Florida, on State Route 9336, less than an hour from the Miami metropolitan area. Miami International is the closest major airport.

Fees: The entrance fee is $10 per vehicle or $5 per pedestrian or cyclist, valid for seven days. Boating fees are $5.

Lodging: Flamingo Lodge & Marina, 38 miles southwest of the main park entrance, offers air-conditioned rooms plus cottages with kitchen facilities year-round. Lodge room rates depend on the season, highest in the winter and lowest in the summer. Visit www.flamingolodge.com. For reservations, call (239) 695-3101 or toll-free (800) 600-3813.

Camping: Three campgrounds (Flamingo, Long Pine Key and Chekika) provide camp sites on a first-come, first-served basis for $14 a night. Camping is free June to August. Call (800) 365-2267.

Food and Supplies: The Flamingo Lodge restaurant offers breakfast, lunch and dinner November to April. The marina store sells food and supplies.

Activities: Several sightseeing boat tours are offered daily through the Flamingo Lodge & Marina (239-695-3101) and Everglades National Park Boat Tours (239-695-2591). Full-day and half-day fishing charters are available. The lodge also rents canoes, kayaks, skiffs, houseboats, fishing poles, bicycles and other equipment.

When to go: Park ranger-led activities occur year-round at Royal Palm Visitor Center and during winter months at additional locations. The best bird watching opportunities occur during the dry season, November through May. The mosquito count is lower in winter months.

For park information: Superintendent, Everglades National Park, 40001 State Road 9336, Homestead, Florida 33034-6733; (305) 242-7700; www.nps.gov/ever.

Ecological Alert: For information about the comprehensive plan to restore the ecosystem, visit www.evergladesplan.org.

For UNESCO World Heritage Site information: Visit the Everglades National Park listing.