There’s nothing like a million fiddler crabs to make you feel welcome.

When the tide recedes from the marshlands on Hilton Head Island, S.C., the coffee-colored mud gets busy. Tiny crabs peek from their burrows, then edge out. The males unfurl their one oversize front claw: a chick magnet. They wave it back and forth, back and forth, to catch a feminine eye. From a grassy trail, I look out on the throng of waving crabs, and it seems like a greeting of sorts.

This is my fourth visit to Hilton Head, and although the crabs have been here all along, this is the first I’ve seen of them.

I’m having a different kind of Hilton Head vacation. We’re ignoring the two dozen golf courses, the countless tennis courts, even the beach, to set out in search of a quieter commodity: nature.

Hilton Head, about 12 miles long and shaped like a shoe, has been home to rich plantation owners and freed slaves. Its current incarnation dates from the mid-1950s and the development of Sea Pines Plantation, a gated resort that’s still a major center of activity; that’s where the island’s familiar red-and-white-striped lighthouse is. Several other developments have been built since, many of them gated, which can make sightseeing a bit tricky.

As it does for us. Bicycling along the public trail that traverses the length of the island, we head for the Sea Pines Forest Preserve, a 605-acre natural area within the resort. The path comes to an end near a gatehouse, where a sign announces that the continuation of the trail, on the other side of the gatehouse, is private Sea Pines property.

A car and a $5 day pass will get you through the gate: If you aren’t a guest or resident of Sea Pines, the only way in is on four wheels.

We finally pull into the preserve’s parking area the next day, it appears that we’re nearly the only visitors.

Bikes are welcome in the preserve, but walking is easy and peaceful. We tread a thick carpet of pine needles that winds beneath tall trees dripping with Spanish moss. An owl hoots, and a marsh hare, a rabbit with short little ears, scoots across our path. The forest gives way to open meadows as the trail leads us to Lake Mary, the largest of three lakes inside the preserve. Here a few folks are assembling to claim their reserved seats on the gator boat.

Hilton Head visitors figure out fast is that the island is loaded with alligators. Big, small and in between, they’re everywhere, and a carefree stroll around any pond can turn heart-stopping when you realize that you’re feet away from stepping on a leathery tail. The gator boat promises a safer up-close look at the creatures. But we pass on spending the $25 and don’t feel as if we missed out: Gators are plentiful, gliding through the murky water and sunning themselves on the shore. Walkers hail one another on the paths to report sightings: There’s a huge one over by that dock! There are two in the grass just around the bend! We don’t linger long; we’re on our way to see the shell ring.

Four thousand years ago, nomadic Indians stopped in these woods every year on their seasonal journeys. They left behind a mysterious wall of oyster shells, heaped a couple of feet high around a circular clearing about 150 feet across. Erosion has taken a toll, but much of the ring is still there, the shells glowing in the light that’s filtered through the leaves above. It’s a little eerie, a little amazing to be standing on ground where Native Americans once camped.

Pinckney Island

The next day’s destination is quite different. Pinckney Island, the largest island in the Pinckney Island National Wildlife Refuge, lies in the waterway that separates Hilton Head from the mainland. There’s no development, just 10 or so miles of grass and gravel trails through 1,200 acres of salt marsh and higher ground.

Big gators live here, too, but the larger draw is an exotic assortment of birds: white ibis, egrets, two varieties of heron, ospreys, painted buntings and more. Around Ibis Pond, they hoot, trill, chirp and caw in a cacophonous din, sometimes joined by the deep boing of a bullfrog; I pull out my iPhone and record it to keep the memory alive. This is the first time I’ve seen wood storks, remarkable wading birds with five-foot wingspans that manage to be both gawky and graceful. Here I also get my first glimpse of the sociable fiddler crabs. I’ve read about marsh snails, and there they are, clinging to the cord grass that rises from the muddy bottom. We leave happy but wondering how we could possibly have forgotten to pack binoculars.

Coastal Discovery Museum

There are a few other nature-related sites to visit, and on our last day, we choose the Coastal Discovery Museum. Housed in the modest-size former home of a plantation owner, the museum traces Hilton Head history from prehistoric times through the present. There’s plenty of information about the local wildlife, including the sea turtles that come here to lay eggs. It’s also the best place to learn about the Gullah people, whose ancestors were brought here from West Africa as slaves and whose culture remarkably survives today. A bus tour that visits historic Gullah neighborhoods leaves from the parking lot.

The museum has a butterfly enclosure, gardens and three boardwalks jutting into the salt marsh. As the afternoon wanes, we walk out over the last boardwalk to a small gazebo over the water eddying below. An interactive display lets me push buttons to hear the calls of the local birds, and mounted observation binoculars ease the pain of not having my own. Suddenly, we realize that it’s late; the museum is closing. Hurrying back across the boardwalk, I spot movement below. The tide has just gone out, and already the mud teems with crabs. They’re waving. I wave back: Goodbye.