Hot Purrsuit

LAGUNA ATASCOSA NATIONAL WILDLIFE REFUGE — Once the weather turns cool, it’s time to put out the traps.

Every fall and winter, biologists and volunteers try to catch, tag and track an elusive, vulnerable animal that hides in the thick brush at the Laguna Atascosa National Wildlife Refuge. It’s the ocelot — a small, lithe, spotted cat that remains on the brink of extinction in the United States, save for the few dozen that live at the refuge.

Catching the ocelot is a tricky task and most days workers return empty-handed. But they persist, because tracking the movement and health of these animals is an important part of ensuring their survival, said Jody Mays, a wildlife biologist at Laguna Atascosa.

“We don’t try to catch each individual one, but a few that we can monitor,” Mays said.

The ocelot is on the federal and Texas endangered-species lists, and as its habitat has dwindled in the Rio Grande Valley, the animal’s future has become uncertain. Mays and other wildlife experts are worried about the health of the refuge’s population and its limited ability to migrate.

“They’re isolated, so they start inbreeding and losing that genetic diversity,” Mays said.

The Laguna Atascosa ocelots have lost 23 percent of their genetic diversity in just two decades, according to blood tests biologists have conducted on the animals.

As the cats become more similar genetically, they become more defenseless to disease, Mays said.

“One disease could come in and wipe them all out,” she said.

Because of its increasing vulnerability, the ocelot has served as a symbol for environmental groups in the Valley and nationwide — a sign that diminishing habitat can have a far-reaching impact on animals.

“I don’t think there’s any better example of what habitat loss has done for a species in the Valley or in Texas,” said Linda Laack, wildlife biologist for Environmental Defense, a national nonprofit advocacy group. “This was a species that once covered much of central and eastern Texas, and it’s now reduced to just a few counties in (the) Rio Grande Valley.”

Morning rounds

With that knowledge, it’s no wonder Mays — accompanied by intern Nova MacKentley on one crisp Wednesday morning — approached each trap with a hush of anticipation. When one of the live traps holds the rare ocelot, she gets an adrenaline rush, she said.

The live traps, which do not injure wildlife, are scattered throughout the refuge. Each one has a separate compartment with a bird inside to serve as bait. The bird also is unharmed because it is just out of the animal’s reach.

The traps regularly capture raccoons, rats, snakes and javelinas, Mays said.

That Wednesday, the refuge’s traps only yielded four raccoons and no ocelots.

“They’re by far our most common capture,” Mays said.

Since November, refuge employees and volunteers have caught and released four ocelots, including one caught two days after the Wednesday trip. The number caught varies each year, from as many as seven some years to only two in others, Mays said.

The latest ocelot caught at the refuge was a young male, in good health, who had never been documented before, officials said.

The ocelot is nocturnal and rarely emerges from its cover of dense brush, which means few people ever see the animal in the wild, Mays said.

She has worked at Laguna Atascosa off and on for more than a decade and has only seen four in the wild. She has also seen an even rarer thing — an ocelot den, with newborn kittens inside. But that was more than 10 years ago.

“The last den we found was in 1997 … and the last juveniles we caught were in 2005,” Mays said. “It concerns me. We should be catching juveniles. It’s a possible sign they’re losing their reproductive fitness.”

A species in danger

During the morning rounds, Mays, and occasionally MacKentley, discussed how different conditions have converged to put Texas’ ocelot in so much danger.

Usually, a species becomes endangered because of one major factor, with other factors contributing. In the ocelot’s case, the major factor is loss of habitat — specifically, the dense brush that once covered this part of the state. Also, the habitat that does exist is fragmented, making it difficult for the animal to migrate and mate. Then, inbreeding hurts their chances. And finally, the ocelot’s biggest killer comes into play: automobiles.

Several Laguna Atascosa ocelots have died crossing the Valley’s highways at night to get to habitat, Mays said. The U.S. Fish and Wildlife Service is working with Texas Department of Transportation to install ocelot crossings at some of those places, she said.

And then there’s the border-fence proposal.

U.S. Fish and Wildlife officials have expressed concern that certain stretches of a proposed fence, once built, would prevent the ocelot from migrating or accessing fresh water from the Rio Grande. Officials were worried about one portion of the fence, in particular, which potentially would have been built on a tract of land adjacent to Laguna Atascosa.

In a recent environmental impact statement, the U.S. Department of Homeland Security recommended moving that portion of the fence to minimize impact to wildlife. Still, officials have said, the ocelot could be affected, depending on where the fence ends up going.

Refuge officials are working with a nature preserve in Mexico to create a corridor for the ocelots on both sides of the border, allowing them to breed and access more habitat, officials say.

A fence along the border could thwart those plans, but it’s hard to know for certain, Mays said.

Tracking the ocelot

If a trap does capture an ocelot, refuge employees have to work fast. They only want the ocelot to be out of its territory for a day, otherwise another animal might move in and claim it, Mays said.

The ocelot is quickly given anesthesia and examined, with a biologist checking the animal’s temperature and getting a blood sample. The ocelot also is injected with an electronic tag that allows workers to identify the animal if it’s captured again. Then, the cat is fitted with a radio collar that gives out a distinct signal. Each collar broadcasts at a different frequency and helps the refuge track the ocelot’s movement and health, Mays said.

If the beeps transmitted over the radio collar speed up, that means the animal is stationary and could be dead, she said. A slower rhythm means the cat is moving.

The employees also take many pictures, documenting each cat’s unique markings for later identification.

Before nightfall, the ocelot is released into its habitat.

Sometimes it’s tough to know how much humans should intervene in the ocelots’ lives, Mays said. For example, one captured cat turned out to have an infection, but treating it would have meant keeping her in captivity for weeks and costing her the loss of her territory. Refuge officials decided to let nature dictate her fate. So far, the cat is still alive.

“Mostly, we focus on alleviating the human impacts, the things we’ve done to affect them,” Mays said.

The refuge mainly relies on funds from the annual Ocelot Conservation Festival in Harlingen, as well as an adopt-an-ocelot program, to buy tracking devices, cameras, rainwater-catching equipment and other tools that benefit the animals, officials said.

Protecting the endangered cat is a worthy cause, Mays said.

“Texas is the only state that has them, and we should try and not lose them,” she said.

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Melissa McEver covers health and environment issues for Valley Freedom Newspapers. She is based in Harlingen and you can reach her at (956) 430-6252.