A former farm site, Estero Llano Grande now boasts an impressive crop of wildlife.
By Wendee Holtcamp
“You’re looking at a former farm field,” says Ruben Zamora, a local high school biology teacher and former TPWD biologist. As I stroll down a boardwalk at Estero Llano Grande State Park in Weslaco, I see a patch of land that would now be almost impossible to plow. Ibis Pond is a lush wetland, with soft stems of bulrush, sedges and water lilies. Constructed wetlands comprise a third of the park’s approximately 200 acres — creating a magnet for shorebirds, neotropical migrants and year-round residents.
Along with park superintendent Martha Martinez-Garcia, park interpreter Shane Mooneyham and Zamora, I explore the park’s trails for birds, as well as any other creatures that happen to cross our path. Their collective passion for wildlife shows as they tell me about the region’s flora and fauna, the park’s history and future plans.
We make our way down the wetland boardwalk, startling a group of American coots that run frantically on top of the water, flapping their wings to get enough speed to take off. “They’re not good fliers,” laughs Zamora. The coots don’t leave the water, but instead stop a few dozen feet away. We’re hoping to spot a northern jacana, a coot-like bird with huge feet common in central and South America. Rarely spotted north of the border, one has taken temporary residence here. It caused such a stir, within a week of posting the jacana sighting on the Internet, birdwatchers had flown in from Mexico, Canada, Washington, New York, Minnesota and Florida (to name a few) just to catch a glimpse.
They’re not the only bird to flock to these new wetlands — over 500 species have been spotted in the lower Rio Grande Valley, and many can be found at the park, which conserves some of the Valley’s last remaining natural land. “The park is an island of habitat in a rapidly developing area,” Zamora says. Unfortunately, over the past century, most native habitat in the region has been plowed under for agriculture or bulldozed for the urban explosion of homes and strip malls. Driving from Brownsville north to Weslaco, I observed nothing but concrete, roads, parking lots, buildings and exotic Washingtonian palms dotting the horizon.
“Ninety-five percent of habitat in the Lower Rio Grande Valley has been lost,” says Martinez-Garcia, “Here we’re trying to conserve land.” The park preserves several habitat types, including Rio Grande delta thornscrub, wetlands, savanna, and a small patch of rare Texas ebony-anacua forest. But at Estero Llano Grande, they’re not merely preserving habitat, they’re creating it, turning an old ag field into the grandeur of watery wetlands, native trees and vegetation, butterfly gardens and scrub forest.
The park officially opened in June 2006, one of nine World Birding Center sites in the lower Rio Grande Valley. As partnerships between federal, state and local entities, the $20 million World Birding Center sites recognize that unless someone sets aside habitat, or restores it, birds will decline and ultimately disappear. The flush of ecotourism dollars from birdwatching or other outdoor exploration gives a community added incentive to preserve or enhance habitat for the species.
Before Estero Llano Grande’s opening, much work went on behind the scenes. Martinez-Garcia supervised the restoration of wetlands, construction of boardwalks, creation of a butterfly garden, and the planting of 3,000 native trees such as Montezuma bald cypress, Texas ebony and Sabal palm. Ducks Unlimited planned and created the wetlands, and TPWD built the boardwalks, cleared old trails and created new ones.
“When I started working here, the only areas in the park that had water were Kiskadee Pond and the Llano Grande,” says Martinez-Garcia. Llano Grande Lake runs along the southeastern edge of the park, and forms the headwaters of the Arroyo Colorado, a river that runs 52 miles northeast, emptying into the Laguna Madre.
We take a look around the park visitor center, with its expansive deck overlooking Ibis Pond. They’ve tried to simulate natural ecosystems with the constructed wetlands, the way the habitat might have looked long ago, but as Mooneyham explains, “We don’t know what it was really like.” In times past, the Rio Grande regularly flooded its banks, sending water into abandoned riverbends or oxbows throughout the region, known as resacas. Estero Llano Grande essentially means, “wet place on the big plain.” Because the Rio Grande dried to a trickle and no longer floods, water for the parks’ wetlands gets pumped in. Irrigation systems keep water in the wetlands year-round. “We can fluctuate the water levels for wading birds,” Martinez-Garcia explains.
Besides creating wetland habitat and restoring native vegetation for birds and wildlife, education and outreach remain a primary goal of Estero Llano Grande State Park. Says Mooneyham, “We need to teach the culture of nature to children and get them to understand that it’s important.”
As we return to the trails, even during the heat of midday, we hear and see a remarkable variety of birdlife: the great kiskadee, a Harris’s hawk lighted upon a branch, and “tea-cup” call of the groove-billed ani. At Grebe Marsh, you can see all three North American kingfisher species — ringed, green and belted. “Birding is fantastic in winter,” says Martinez-Garcia “You don’t have a lot of foliage so you can see the birds well. We’ve got birds of every color.”
We walk on a path into another of the park’s habitats, an ebony-anacua forest, one of Texas’ rarest plant communities. Zamora points out the scratchy texture of the anacua (or sandpaper tree) leaves, and the ebony’s deep green foliage. Historically associated with well-drained soils near resacas, ebony-anacua forests have become thornscrub as the Rio Grande dried.
“There’s an indigo snake,” Zamora whispers, but it slips into the brush. The large non-venomous snake will fan out its neck like a cobra when upset. These blue-black beauties became known to farmers as a “snake to have around” because of their habit of eating rattlesnakes, Zamora says. Despite this, they’ve suffered from habitat loss and Texas lists them as a threatened species. Rare Texas tortoises also live here, looking like miniature versions of Darwin’s Galapagos tortoises and just as endearing. Heavy pet trade exploitation made their population plummet.
As we turn over stones, I find the recently shed velvety skin of a tarantula and a small scorpion. We’re discussing its nemesis, the tarantula hawk, when one appears — a large wasp with rust-colored wings and a tough exoskeleton that keeps tarantula fangs from penetrating when they tangle.
To fully understand the grandeur of this place, we’ve got to observe it like the wildlife might. Estero Llano Grande State Park lies in an arid ecoregion within the South Texas Plains known as the Tamaulipan thornscrub. Thornscrub is aptly named; everything has thorns, briers, stickers, or prickles and if you rub it the wrong way, ouch. Animals in the region have evolved and adapted. Birds manage to glean berries perched atop thorn-bearing acacia, snake eye, brasil, mesquite, and spiny hackberry shrubs and trees, and mammals hide out from predators under the prickly branches.
In this region, not only does the Rio Grande meet the sea, but temperate meets tropical. Scientists call the meeting place between ecosystem types “ecotones,” which are well known for high biodiversity because species from multiple habitat types converge in one area. In the lower Rio Grande Valley, neotropical migrants funnel through as they fly to and from Central and South America. The region also represents the northernmost range for many species: red-crowned parrots, green jays, buff-bellied hummingbirds, groove-billed anis and Altamira orioles — the park’s signature bird.
The bird ticker keeps edging upward. First 485, then 500, and as of 2006 over 510 bird species have been documented in the Valley. Only Texas and California have more bird species than the lower Rio Grande Valley’s four-county region (Hidalgo, Starr, Cameron and Willacy). As the World Birding Center Web site rightly claims, “The Rio Grande Valley hosts one of the most spectacular convergences of birds on earth.” And right in its center, Estero Llano Grande State Park has created a watery wetland haven for the birds at this “wet place on the big plain.”