In the Alamo Inn's gift shop, a whiteboard lists recent bird sightings in the valley: Morelet's seedeater; ferruginous hawk; crimson-collared grosbeak; golden-crowned warbler.
"We didn't see these birds at all last year," said Keith Hackland, who with his wife co-owns the inn, in the small Texan town of Alamo, which caters to birders and other nature tourists.
For Hackland and the guides, outfitters, shopkeepers and other locals who make their living from nature tourism—which generates $463m a year and supports more than 6,613 jobs in the lower Rio Grande Valley according to a 2012 Texas A&M analysis (the most recent available)—this should be a blockbuster year.
The rare bird sightings kept coming through the winter, and the spring migration is just getting under way. But while the birds may be showing up en masse, the birders who want to spot them are not.
Hackland, who also chairs Texas Birding, a not-for-profit organization that promotes birding in the Lone Star state, estimates that business this winter—one of the valley's high seasons—may have fallen by as much as 40%. "For a small business like us, that's quite scary," he said, adding that he may have to lay off some of his birding guides this summer.
Hackland and others in the industry believe that the new sections of border wall going in just up the valley in the Lower Rio Grande Valley national wildlife refuge—and the national debate over Donald Trump's push for a "big, beautiful wall" along the entire 1,954-mile border, much of which is in Texas—have a lot to do with the downturn.
The structures, part of a controversial project funded by Congress last year that calls for erecting 33 miles of new barrier in south Texas, made national headlines.
In Texas, the border follows the meandering Rio Grande, and many of the state's best birding spots are along its forested banks, including several national wildlife refuges, state and county parks and privately owned nature preserves. Since the walls can't be built in the river or its floodplain, they have to be constructed on the lands adjacent to it. Would-be visitors are calling with concerns about criminals streaming across the river-border, Hackland and others in the industry say, or worried that all the habitat is being bulldozed. Neither scenario is true, he adds.
I actually had one call from someone who canceled his reservation, saying he didn't want to see bulldozers
"I actually had one call from someone who canceled his reservation, saying he didn't want to see bulldozers in Santa Ana [national wildlife refuge]," he says. "I had to tell him it's not happening."
While a 2005 law has allowed the Department of Homeland Security to waive more than two dozen environmental laws to expedite the 18ft steel bollard fence, Congress exempted Santa Ana from the project, and later also spared Bentsen-Rio Grande state park and the nearby National Butterfly Center, a privately owned preserve.
Others remain convinced that the area is unsafe. While Customs and Border Protection has identified the Lower Rio Grande Valley as a high-traffic area for illegal border crossings, fewer crimes occur in Texas's border towns than in its major cities. For example, while 665 violent crimes were committed for every 100,000 residents in Dallas, south Texas's Edinburg and Brownsville saw about 400 such crimes for every 100,000 people, according to a 2016 analysis of FBI crime data by the Texas Tribune.
"The constant rhetoric of bad people or criminals or terrorists coming across the border is really affecting us," said the Texas Birding director Nydia Tapia-Gonzales, adding that other hotels and local guides that cater to nature tourists also have reported a drop-off in sales this year. "People think it's not safe. But that is not the case. When they come here they realize it's wonderful."
It's south Texas's unique geography that makes it a bird mecca. This 240-mile final stretch of the Rio Grande is an ecological crossroads where the tropical and the temperate mingle, attracting more than 400 bird species and several endangered mammals, including the elusive ocelot and jaguarundi.
But if visitation continues to decline the loss will hit especially hard here; the five Texas counties with the highest poverty rates are all in south Texas, census figures show. If the nature tourists stop coming, some of the natural areas along the border may have to close, many in the industry fear, and their businesses along with them.
While Bentsen-Rio Grande state park, which lies near the refuge tract where the new section of fence is under way, received a reprieve, environmental groups worry that an emergency declaration that Trump issued earlier this year to secure further wall funding could allow him to override those protections. If a wall goes up and visitation at the park, which attracts about 30,000 visitors each year, goes down, funding could dry up.
"Visitation is a key component to determining how long a park remains open to the public," Josh Havens, a spokesman for the Texas department of parks and wildlife, said in an email. "I cannot say what impact a fence may have on park visitation. Only time would tell."
On a recent afternoon at the park, which lies south of the town of Mission, an older couple walked along the levee behind the visitor center where a portion of the wall was initially planned. Gary and Sharon Aitchison of Davenport, Iowa, visit the park and the other natural areas along the border often. They oppose the border barriers and they worry about how the walls will affect their visits and the businesses they frequent.
"That's how many people here make their living," said Sharon Aitchison. "We've been to Florida, we've been to Arizona. But we've always felt that people here are just so welcoming. They understand that we really help their economy. And we're happy to help their economy if they allow us to enjoy their area."