Wildlife Crossings in South Texas to Help Protect Ocelots

In the simplest of terms, they're trying to herd cats.

The Valley Morning Star reports the dozen wildlife crossings being constructed on two highways, which have taken more than their share of ocelot lives, are experimental, wildlife officials say.

The plan is for chain-link fencing along FM 106 and State Highway 100 in Willacy County to funnel ocelots to the underpasses, allowing them to bypass the highways safely.

So far, it's been a grim year and a half for the endangered ocelots.

Between June 2015 and April of this year, seven ocelots -- six males and a female -- are known to have died after being hit by vehicles in South Texas. In all, the endangered Texas ocelot subspecies numbers about 80, with around 15 of them at Laguna Atascosa do more to help ocelots rebound here than anything else -- just getting ocelots off roads.

"This is new, basically an experiment," he said. "Nobody's really tested sufficiently how well these crossings will work, but we're really excited."

Small, fast and moving at night, ocelots have had a long and losing experience on the remote Texas highways that cut through the diminishing habitat where they're still found.

"The fencing will go along parallel to the road on each side of the road, and will funnel -- hopefully -- as much wildlife as possible into the crossings," Blihovde said. "We're hoping white-tailed deer will use them in some cases, and other species, too."

The massive concrete underpasses are different sizes, but are sufficiently wide and tall to accommodate deer, ocelots, bobcats, raccoons and more.

The underpasses are different sizes depending on how far they burrow under a highway, based on a concept called "openness ratio."

"Basically you're looking at how wide, how tall and how long it is," said Hilary Swarts, a biologist and an ocelot expert for U.S. Fish and Wildlife who is based at Laguna Atascosa.

"So a crossing going under 106 can afford to be shorter and skinnier than one going across 100 which has to go across four lanes rather than two," she said. "The key element is that the animal, when it gets to the opening on one side, it can really see the other side, can see that it's not just a pinpoint of light but a viable pathway to good habitat."

The underpasses also have "catwalks" 18 inches high and 18 inches wide, that allow an ocelot to cross under a highway without getting its feet muddy and wet.

Cats gotta be cats, after all.

"Ocelots do swim," Swarts said. "That said, like any cat, they're not going to want to walk in a dingy path of muddy water to the other side.

"Our goal is always to make it more enticing to use the underpass and stay off the road," she said.

The $8 million in funding for the wildlife crossings was paid by TxDOT out of the department's discretionary fund. Blihovde and other federal officials have been effusive in their praise for TxDOT's support in funding and building the underpasses.

"We really are proud of the relationship that we've got with TxDOT right now," Blihovde said.

This isn't the first effort TxDOT has made to try to make life near state highways easier for ocelots.

"Efforts have been made before to protect the ocelot on State Highway 100," said Octavio Saenz, a TxDOT spokesman. "Perforations were made along the concrete barrier that separates the two directions of traffic."

With the new fencing, both wildlife officials and TxDOT are hoping for even better results.

But the effectiveness of the wildlife crossings, at least for ocelots, also is dependent on the type of habitat along the roads where the underpasses are located.

"Of the many underpasses previously built or modified for ocelots in South Texas, some of the culverts on FM 106 will have the best chance of being used," said Dr. Michael Tewes, a professor at Texas A& M University-Kingsville and an ocelot expert. "One important factor for a successful culvert will be whether there is ocelot habitat (i.e., dense thorn scrub) on both sides of the road where the culverts are located."

In the end, wildlife crossings or no crossings, Saenz said drivers on FM 106 and State Highway 100 or any road near the Laguna Atascosa refuge or in ocelot habitat farther north can do their part, too.

"We would like to remind drivers to take caution when driving through these areas that have dense brush on either side of the road," Saenz said.

"Furthermore, anyone who sees an ocelot -- either dead or alive -- must report it immediately," he added.