THE VINE-CHOKED FOREST WAS LUSH and impenetrable. Sturdy palms and ebony trees blocked out most of the harsh midmorning sun and the world beyond. Walking quietly along the twisting trail of the Sabal Palm Grove Sanctuary, accompanied by the soothing rustle of the broad palm fronds, I was seized by the delicious sensation of being Somewhere Else, somewhere outside Texas.

I get that feeling of dislocation a lot in the Rio Grande Valley, that flat crescent of land that hugs the river for some one hundred miles at the southern tip of Texas. Fly into the Rio Grande Valley International Airport at Harlingen, and the neatly plowed, symmetrical fields will fool you into thinking of the midwestern breadbasket rather than the gateway to Mexico. Cruise the often-bypassed business routes of U.S. 83 and U.S. 77, and all the fruit- and vegetable-packing plants and faded hotels, motels, and trailer parks will recall Southern California before the subdivisions squeezed out the citrus groves. Get behind a slow-moving vehicle, and you might wonder if this is the Mexican interior or St. Petersburg, Florida, depending on whether the motorist is a pachuco lowrider or a retiree. Appearances are peculiarly deceiving here.

Of all the memories I have stored up in more than thirty years of visiting the region, the ones that burn brightest revolve around the hidden Valley, the one filled with unexpected, even exotic, natural and historic delights that exist nowhere else in the state. You can get a taste of this wilderness while enjoying other diversions at the usual tourist destinations of South Padre Island, Port Isabel, Brownsville, and McAllen.

Even though 95 percent of the Valley’s wildlife habitat has been destroyed by agriculture and urban development, the small part that remains is a revelation. The Valley’s geography has blessed it with a remarkable diversity of tropical plant and bird life, much of it otherwise found only in Mexico. You don’t have to be a birdwatcher, a fisherman, or a hunter to appreciate butterflies with strange markings and even stranger colors, raucous bright chartreuse green jays, or the simple solitude of tramping down a dirt path surrounded by odd-looking prickly plants and trees you thought existed only in greenhouses.

However, if you happen to be thrilled to see new wildlife species, the Valley harbors animals seldom, if ever, seen elsewhere in the United States—the fluorescent turquoise-and-black snake known as the speckled racer; the graceful ocelot, a spotted cat that has been hunted almost out of existence; and the even more elusive jaguarundi, a dark, low-slung feline that ripples through the brush like water through reeds. While you may never spot them, knowing they are lurking in the thorny underbrush is a vicarious pleasure.

A plan is under way to return more of the Valley to the wild, in the form of the 110,000-acre Lower Rio Grande Valley National Wildlife Refuge, an almost contiguous greenbelt that will meander along the river from Falcon Dam to the Gulf once the remaining parcels of land are acquired over the next five years or so. (About half the land has been purchased.) In the meantime, you can sample the wild side at “islands” that the national refuge will eventually link together—the Sabal Palm Grove Sanctuary, the Laguna Atascosa National Wildlife Refuge, the Santa Ana National Wildlife Refuge, the Bentsen—Rio Grande Valley State Park, and other local pocket preserves.

October and November are an ideal time of year to experience the Valley. Temperatures have become almost bearable, with highs in the 80’s and low 90’s, and lows that fall below 70 degrees in the evenings. This is the Valley’s off-season for tourism. The summer crowds have departed, and the seasonal residents known as Winter Texans won’t start arriving until Thanksgiving. Hotels drop their rates to the most affordable of the year. For example, a double at the Radisson (512-761-6511), the best hotel on the South Padre beach, is a tolerable $89 in the off-season; a smaller-sized double at Port Isabel’s charming if less-posh Yacht Club Hotel (512-943-1301), with its excellent restaurant, is half the price.

Our family’s first morning of exploring began at the Sabal Palm Grove Sanctuary, a 35-minute drive from South Padre. “You’re looking at five or six species you won’t see anywhere else in the United States, outside the Valley,” said Rose Farmer, the manager of the refuge, quietly pointing out pheasantlike chachalacas, spectacular green jays, bright-yellow-and-russet kiskadee flycatchers, hooded orioles, and several buff-bellied hummingbirds hovering around the bird feeders outside the small visitors’ center. Since we were 6 miles southeast of Brownsville and 160 miles north of the Tropic of Cancer, her comment wasn’t surprising.

Survival is a risky proposition on the border, Farmer explained, which is why the National Audubon Society purchased the land for the palm refuge in 1971. It began with 32 acres of Sabal texana palms, all that was left of a native subtropical palm forest that once covered 40,000 acres. Today the palms have spread throughout the refuge’s 172 acres, room enough to make you feel as if you’re in the land that time forgot.

After walking the palm grove trail, browsing in the visitors’ center (knock if the door is locked), and watching the action around the feeders, we followed Farm-to-Market Road 1419 east and north until it intersected with Texas Highway 4, the road to Boca Chica—the southernmost stretch of coastline in Texas. This is rough, forbidding country—“loma tidal flats” is the technical description—evidenced by the crumbling gates of a failed development named Palmito Hill. We stopped to check out the historical marker for the last land battle of the Civil War (May 12 to 13, 1865), a site still so utterly removed from civilization that it is small wonder that the blue and gray were duking it out weeks after Lee surrendered to Grant.

The scenery became increasingly minimal until it was distilled to sand, scrub, and sky, with an impressive bunker of dunes marking the beginning of the beach. There is no there there in Boca Chica: no settlements, services, creature comforts, or amusements other than fishing, swimming, beachcombing, crabbing, and lollygagging. Pelicans, herons, roseate spoonbills, even the occasional peregrine falcon congregate here, not to mention fishermen boating over from Port Isabel and South Padre. The isolation definitely has its fans, judging from the pickups and campers parked along the seven-mile stretch of beach between the jetty across from South Padre Island and the mouth of the Rio Grande.

Doubling back on the highway, we turned on FM 511 to the Port of Brownsville, the home of Texas’ largest shrimp fleet. Inside the gates of this burly port is the Famous Mexican Crow Park, a birders’ euphemism for the Brownsville city landfill, where Mexican crows, never before seen north of the border, have taken to hanging out. On this particular day the crows were elsewhere, though several hundred squawking gulls flapped above the garbage heap. The man at the landfill entrance gladly gives directions and updates on crow sightings.

Continuing on Texas Highway 48, toward the border, we stopped at Los Camperos (1440 International Boulevard) for a charbroiled half-chicken a la parrilla with tortillas and hot sauce ($4.75) before driving a few blocks to the end of the road at the Gateway International Bridge. To the left is Fort Brown, the site of the Fort Brown Hotel and Resort (a recommended lodging choice with beautifully landscaped grounds; double room, $77; 512-546-2201), Texas Southmost College, and the best examples of palm-lined resacasor oxbow lakes—in a city famous for its resacas.

Turning right on Elizabeth Street, we passed through Brownsville’s oldest residential neighborhood, an area dominated by a surprising number of Spanish-style homes with verandahs and balconies. The Stillman House Museum (610 E. Thirteenth), one block north of Elizabeth, is the best-restored example of these period pieces.

Another right on Sixth Street brought us to the Gladys Porter Zoo (Sixth and Ringgold; admission $4.75 adults, $2.50 children; 9—5:30 Monday through Friday, 9—6 Saturday and Sunday). Budgeting about two hours, we commenced a leisurely stroll through Texas’ most impressive collection of wildlife. In addition to the requisite elephants, giraffes, lions, tigers, and flamingos and an excellent petting zoo that pleased the kids no end, the zoo had several exhibits of Valley natives, including the Stealth-like jaguarundi. Most of the animals’ open-air enclosures are separated from the public by moats instead of bars.

If we had stayed in Brownsville, we would have headed to Los Ebanos Street, one block west of Central Boulevard, where flocks of parrots congregate about an hour before sundown. But we went back to South Padre and the Sea Ranch Restaurant and Marina, where we had our choice of taking the Sunset Bay dolphin-watching boat cruise ($12 a person for a two-hour ride), which departs from a dock next to the Sea Ranch, or eating dinner. Since the Sea Ranch is one of the few places on the island where you can enjoy fresh-caught seafood with the added bonus of a scenic picture-window view of the docks and assorted sport-fishing boats, we voted to eat. The entrées were well prepared, and prices were moderate: broiled grouper was $10; red snapper $15.

The next morning began with an early wake-up call and a half-hour drive to the Laguna Atascosa refuge (admission $2 a vehicle). We timed our arrival at the entrance of the fifteen-mile Bayside Loop road shortly after sunrise, just in time to catch the morning rush hour of critters along the pavement—far more animals than we would have seen later in the day. Lizards shot across the road, hundreds of rabbits froze motionless as our car approached, white-winged doves and bobwhite quails careered from the brush, and a huge Texas tortoise lumbered along in the middle of the asphalt. Overhead, hawks and falcons flew surveil-lance missions while a great blue heron stood at attention in the shallows of the laguna, studying the calm surface of the water and occasionally plunging its long beak into the water in search of an appetizing tidbit. When we walked the Paisano foot trail, the boys argued over who would be the first to sneak up on the next batch of hapless rabbits. The 45,000-acre refuge, the biggest chunk of native habitat in the Valley, is at full occupancy during fall and spring, when migrating waterfowl from all across North America stop here for rest and sustenance.

We made sure to return to the island by ten o’clock, because that is when Ila Loetscher, the celebrated Turtle Lady, opens her back yard to visitors. The half-hour show on the deck at Sea Turtle, Inc. (5805 Gulf Boulevard; open Tuesdays and Saturdays; admission $2 adults, $1 children), was an inimitable combination of silliness and seriousness. Aided by an assistant, the feisty 85-year-old Loetscher dressed up her acquiescent reptiles—some weighing more than one hundred pounds—in wigs and hats, got them to wave their flippers, and even cajoled the audience into shouting in unison, “Howdy-do, Texas” and “We love turtles too.” But amid the nonsense, she painlessly slipped in some facts and a lecture on the hazards that turtles, especially the endangered Kemp’s ridley, face from both nature and man. We bought postcards and turtle souvenirs on the way out.

Afterward, we went to Isla Blanca County Park, at the southern tip of the island ($1.50 a vehicle), cruised by Dolphin Cove to look in vain for dolphins, walked past the fishermen on the jetty, and toured the University of Texas—Pan American Coastal Studies Laboratory (open 1:30—4:30 daily except Saturday; donations accepted). The anonymous building behind the beach pavilion is a research facility, but a roomful of displays on the Gulf included mounted specimens and aquarium tanks with local marine life. My seven-year-old was smitten with the sea urchins; the graceful sea robin, with its winglike fins; and a tiny octopus.

Then we packed up our belongings and headed west toward McAllen, veering off the expressway to pass through Mission and Weslaco on the business route of U.S. 83. At the intersection of Val Verde Road near Donna, we paused momentarily at the Val Verde RV Park to ogle the ruins of the ornate white stucco bathhouse and swimming pool where Bette Davis once reputedly frolicked. We sighed, thinking about Mr. Rock Around the Clock himself, Bill Haley, who managed the spread until his death in 1980, and couldn’t resist tapping our feet to a rock and roll beat in his memory.

A few miles farther up the road, we pulled in to inspect the venerable San Juan Hotel, one of the Valley’s oldest, a charming structure with a mission-style facade, a small courtyard, breeze-ways, and neat if unspectacular rooms (double rooms $26—$40; 512-781-5339). We opted for the less-historic but amenity-loaded Doubletree Inn, a.k.a. Casa de Palmas, the restored grand hotel in downtown McAllen (double rooms start at $68, includes breakfast; 512-631-1101).

After unpacking, we made a beeline for our favorite Mexican food standby, Johnny’s (1010 Houston Avenue, at the corner of South Tenth), to split a botanas platter of fajitas, flautas, quesadillas, guacamole, and frijoles. At $25, the platter easily filled up the four of us, but we grieved when we learned that the complimentary marinated onions had been discontinued when the restaurant was remodeled and expanded.

The next morning we drove twelve miles southeast to the Santa Ana National Wildlife Refuge, at FM 907 and U.S. 281, the jewel of the mid-Valley. This compact two-thousand-acre forest on the banks of the Rio Grande is home or a rest stop to 377 species of birds. From Thanksgiving to May, hour-long guided tram tours on the park’s main road tell you what is lurking in the tangle of vegetation a few feet away, but the trams run mostly during the middle of the day, when most of the residents are taking siestas (tours $2.50 adults, $1 children under twelve). Arriving early and exploring on foot, we saw much more.

Fifteen minutes away in Weslaco, we got another whiff of the wild inside a tiny twelve-acre patch of green underneath a lush canopy of leaves that offered respite from the quickly warming sun. The plot is technically the back yard of Jim and Cyndy Chapman, plus a citrus orchard gone fallow and other donated parcels of property, but it is open to the public by appointment (tours arranged through the Audubon House, 512-968-3275). Cyndy Chapman, the head of the Wildlife Corridor Task Force, which helps coordinate federal, state, municipal, and private refuges, started this pocket preserve several years ago, although the city kept sending in crews to mow the grass. “This is not a weedy lot. It’s a forest—a mid-Valley riparian thorn forest to be exact,” she insisted. It’s also a birding spot, where visitors can catch a glimpse of parrots and other exotics. “You should have seen it the day three thousand Mississippi kites came though here,” she enthused.

Another perspective of Chapman’s thicket can be gleaned from the picnic table behind the offices of the Frontera Audubon Society (1019 South Texas Boulevard) around the corner. To arrange a visit, call Sylvia Juarez at the Audubon House (512-968-3275). Six blocks away is another pocket preserve, the Valley Nature Center (301 South Border). By the way, Frontera Audubon maintains a 24-hour birding-alert hot line (512-565-6773).

Weslaco is also a good spot for breakfast or lunch, either at Keno’s Cafe (253 South Texas Boulevard, just off FM 88), for American-style fare, or at Armando’s, a block farther north, for taquitos, breakfast tacos, and other Mexican food.

From Weslaco, we were back on the U.S. 83 expressway, westbound, bypassing McAllen and Mission, for the Los Ebanos turnoff at Sullivan City. Los Ebanos, a village hidden in the thorn forest at the end of FM 886, three miles south of U.S. 83, sits on the north side of a river ford that has been used since the 1740’s. Here is a most unusual transit to Mexico, a metal barge accommodating three vehicles and maybe fifteen pedestrians that runs on the sweat and muscle of four men pulling on a rope.

The gentleman who collected our money at the tollbooth in the United States ($1 a vehicle, 25 cents a person) dispelled the rumor that the archaic ferry is not long for this world. “They have been saying they are going to build a bridge here since 1950,” said Oscar Simo, laughing.

Three minutes later, we were in another country. Less than two miles down a dirt road on the Mexican side is the town of Díaz Ordaz. The plaza, normally the hub of activity in a Mexican community, was eerily quiet. Instead, we found all the commerce and activity some eight blocks away, along Avenida Miguel Hidalgo, where Highway 2, the Mexican border highway, cuts through the settlement. Díaz Ordaz doesn’t have much in the way of gringo trinkets other than woven plastic shopping bags, lotería board games, and liquor. But you can soak up plenty of local color as you amble along. The modern Miramar seafood restaurant, at the corner of López Mateos and Sexto, was said to be the best in town, but we skipped lunch because there were more things to do and places to see. Besides, the ferry shuts down at 3:45 daily.

We should have known better than to hurry, though, because when we arrived at the ferry crossing, the crew was lunching on tortillas, bologna, and white bread under a shady ebony tree. We sat down, slowed down, and waited with them—there’s a different sense of time on both sides of the frontier here.

Back in the USA, we meandered along the little streets of Los Ebanos, stopping to marvel at all the brightly decorated memorials in the town cemetery, where the riot of colored artificial flowers made it look like the liveliest place in town. At the junction of U.S. 83, we turned east; Rio Grande City, Roma, and Falcon Dam to the west would wait for another trip. About four miles down the highway, at FM 1427, we swerved south into the settlement of Peñitas, whose historical marker traces the town’s founding to the 1520’s, when stragglers from the ill-fated Narvaez expedition settled there, according to local lore.

Just before the railroad crossing, we turned left onto a small paved road, taking a quarter-mile detour past low-roofed clapboard and adobe homes nestled under the ebony, ash, and palm trees, another surprise slice of the hidden Valley.

We continued east on FM 374, then turned right on FM 2062, the entrance to the Bentsen—Rio Grande Valley State Park, the third island refuge along the river, five miles southwest of Mission ($3 a vehicle). The 588-acre park of resaca woodlands and dry chaparral emphasizes recreation activities over the pure back-to-nature experience typical of Laguna Atascosa and Santa Ana. There is an overnight camping area with hookups and picnic facilities and a boat launch on an oxbow lake. The park has two hiking trails, including a two-mile route to the river, which beckoned even in the midafternoon. The path ended amid the canebrakes on the banks of one of the prettiest stretches of the Rio Grande below Falcon Dam. We didn’t encounter another soul on the path, which rated a few extra points on the solitude scale.

More history was only a few minutes east, just off the section of U.S. 83 known as Military Highway, south on FM 1016. Atop the only hill visible for miles around was La Lomita Farms (open Monday through Friday), a sand-brick-and-red-tile structure imposing enough to have been inspired by mythical Transylvania. Constructed as the Oblate Fathers Novitiate, the building was converted to a state mental health facility in 1974. It is worth a visit if only to see the reliquary in the small chapel. Inside the glass display case are various religious artifacts, notes, and the bone fragments of Father Pierre Yves Keralum, the so-called Lost Missionary, who disappeared in November 1872 while traveling to a nearby ranch.

Back down the hill, we followed the sign pointing to Pepe’s on the River, a funky thatched-roof open-air palapa bar and restaurant with the requisite strand of yellow light bulbs hanging over the patio. Pepe’s is pleasantly kicked-back most of the week but shifts into full-tilt boogie on Sunday afternoons, when bands play and boats and jet-skiers promenade along the river. On the way out, we stopped next door at the site of the original La Lomita mission, where the tiny whitewashed chapel, constructed in 1865 and rebuilt in 1899, is the only structure on the grounds that has survived the assorted hurricanes that have leveled the rest of the mission. Particularly intriguing was the grotto in the back of the chapel adorned with photographs, plastic flowers, scrawled petitions (“Help me find love”), and shiny metal Christmas ornaments.

Back in McAllen, we had our last supper at Casa del Taco (1100 Houston, off South Tenth), next door to our once-beloved Johnny’s. We passed up the enchiladas americanas—covered in chili and yellow cheese—in favor of sombreros, another Valley specialty, consisting of grilled sliced beef, chicken, or pork sautéed with tomatoes, onions, bacon, and green peppers, smothered in melted white cheese, and topped with a “sombrero” of flour tortillas ($5.95—$6.50). A bowl of cilantro-spiked charro beans came on the side. It was a wonderful gooey mess. Tip: The rear dining room and bar is where the action is—strolling mariachis and then some.

As I dozed off that night, visions of walking the wild Valley, through the tangles of brush and thorn forests all the way to the lush palm jungle, danced in my head, accompanied by the sights and sounds of colorfully plumed birds and exotic beasts. That prospect—and the memory of three days of being Somewhere Else without leaving the state—plunged me into a deep, satisfying sleep.