MIAMI - The heart of winter in South Florida may be the best season to explore the three national parks that surround the region: Everglades, Biscayne and the Big Cypress National Preserve.

Cool breezes, the absence of insects and lack of rainfall make hiking and biking more comfortable. Yet there’s still enough water around to enjoy canoeing and kayaking in many areas. These expansive wilderness areas invite visitors to become adventurers - to paddle secluded mangrove creeks, follow trails used by bears and panthers gaze at gators up close, and marvel at a cornucopia of birds that make winter homes here.

For first-time visitors not sure how to get around or what to look for, all three parks offer ranger-guided adventures, many of them free. One of the most popular is a 24-km bike ride under the full moon at Shark Valley, the northernmost entrance to Everglades National Park. On a recent evening, a group of 20 cyclists joined park ranger Eric Riordan as he conducted a three-hour ride along the park’s roadway used for cyclists, walkers and a tram. At 5 p.m., dusk was just settling in. To avoid disturbing wildlife, the bikers carried no lights, except for glow sticks worn on their backs to prevent collisions.

"I love what happens in national parks at night. It’s all different," Riordan told the group. "This is all about using the senses."

The first half of the ride followed a canal to a 50-foot observation tower. Along the way, the cyclists encountered dozens of roosting birds: sleek black cormorants, snowy egrets, tri-coloured herons, even an occasional wood stork. The alligators seen so frequently in the canal and along the banks in daytime were nowhere in sight, burrowed in the muck for warmth, Riordan said.

A report that hundreds of roseate spoonbills were nesting near the park’s signature observation tower made some some cyclists anxious to pick up the pace. Along the way, the group made a few stops - to examine a gator hole next to a culvert pipe (the gator was missing) and to snap photos of great blue herons in mating plumage. In the silence, the wind through the sawgrass sounded like the ocean. By the time the group reached the 50-foot- spiraling tower, the sky was dark. Though the full moon had not risen yet, the hundreds of fluffy white shapes were visible in the nearby trees. Not spoonbills, it turned out, but wood storks. A couple large gators cruised in the slough below, along with a few turtles and some flopping gar and catfish.

The bicyclists lingered, making sure their glow sticks were intact before beginning the return ride. The trip back into a strong northwest breeze was more taxing than the first leg. The moon still refused to rise, but riders could make out the path from the distant glow of the Miami metropolis. Still, they were a bit disconcerted to pedal along in the murk, hoping no swamp creatures would dart out in front of the bikes. Following the glow sticks, the bicyclists arrived at the park entrance in groups of twos and threes without any mishaps.

After most of the riders had packed their bikes into cars and started home, the moon appeared. And the Everglades began to sing. Squawking herons, rustling sawgrass and cormorants burping like little kids formed a nocturnal chorus both dissonant and harmonic, just like the Everglades itself.

IF YOU GO:

Through March, numerous ranger-led activities are offered at Everglades and Biscayne National parks and the Big Cypress National Preserve; reservations may be required. Fees range from none to about $35. Here’s a sampling:

EVERGLADES: Shark Valley is off U.S. 41 (Tamiami Trail) about 30 km west of Krome Avenue in Miami. The main park entrance is southwest of Homestead; tours here leave from Royal Palm Visitors Center, near the entrance, and Flamingo (about 48 km from the main park entrance). Information: www.nps.gov/ever or 305-242-7700. Tours at Flamingo: canoe adventures, bird walks, discovery walks. Royal Palm Visitors Center: bike hikes, slough slogs, hammock and trail walks, Nike missile site tours. Shark Valley: cycling, full-moon bike rides, tree island ramble.

BISCAYNE: Biscayne National Park’s Convoy Point Visitor Center, 9700 SW 328th St., Homestead. (Only one entrance by land). Information: www.nps.gov/bisc or 305-230-1144. Tours: Guided canoe trips at Black Point, Jones Lagoon all-day canoe adventure.

BIG CYPRESS: Big Cypress National Preserve’s Oasis Visitor Center, 52105 Tamiami Trail, East, Ochopee, about midway between Miami and Naples. The Big Cypress Swamp Welcome Center is at 33000 Tamiami Trail East, Ochopee, about five miles east of SR 29. Information: www.nps.gov/bicy or 239-695-1201. Tours: swamp walks, canoe trips, Deep Lake and Gator Hook hikes, off-road vehicle tours, Bear Island bike ride and an evening boardwalk stroll.