PEST CONTROL: Refuge to combat disease tick with cattle, insecticide-laced deer feed

Refuge to combat disease tick with cattle, insecticide-laced deer feed

Port Isabel-South Padre Press

Herds of cattle will soon be coming to the Laguna Atascosa National Wildlife Refuge (LANWR) north of Laguna Vista.

That’s the word from officials as the U.S. Department of Agriculture (USDA) and the U.S. Fish and Wildlife Service (USFWS) struggle to deal with disease-carrying arachnid known as the cattle fever tick, which threatens cattle ranchers locally and potentially across the state.

Much of Deep South Texas has been under permanent quarantine due to the pervasive arachnids since 1943, but as populations of native white tail deer and non-native nilgai have skyrocketed, the cattle industry fears it may lose control of the ticks.

Nilgai are a type of antelope native to the Indian subcontinent. Brought to the state in during the last century to fuel exotic game hunts on Texas’ broad ranchlands, the animals have since flourished throughout the southern portions of Texas, become nuisances that destroy rare habitat and serve as hosts for the ticks that carry the cattle fever disease.

They, along with white tail deer, live in large numbers on refuge and nearby lands. Previously, refuge officials have tried to control the tick population by offering several public hunts and conducting nilgai harvesting events by air. But, it hasn’t been enough.

As a result, the USDA began conducting an environmental assessment to seek comment about two potential methods for dealing with the issue.

“Alternative A, was to continue to do what we have been doing, and that’s removing nilgai, trying to reduce the population of white tailed deer,” explained Refuge Manager Boyd Blihovde during an interview late last month. “And then other techniques that we’ve been doing, like prescribed burning,” he said.

The second alternative involves more novel approaches, including the use of ivermectin-laced corn feeders for the deer. Ivermectin is an insecticide that kills the ticks. The second approach involved allowing cattle to graze on the Refuge.

“It’s counterintuitive. It’s the primary host. Why would you put the primary host out there?” Blihovde said.

“Well, the reason is, the ticks get onto these tame, controllable cattle, just like they would white tailed deer or nilgai, so a rancher can easily round those cattle up, treat the cattle, put them back onto the landscape to kill ticks. They can’t do that very well with the wild animals, like nilgai or deer because they’re so wild,” he explained.

The cattle placed on the refuge would be treated for the ticks and the hope is that the arachnids would latch onto them rather than nilgai or deer. “That’s the whole premise behind that technique is to sort of act like a vacuum for ticks, using cattle,” Blihovde said.

The cattle grazing would be carefully controlled and regulated, Blihovde said. An industry expert would determine how many head of cattle could safely be sustained in the grazing areas. And they would be rounded up every few weeks.

Blihovde estimated that approximately 25 cows would be grazed on units spanning between 1,500 – 3,000 acres in size. Only female cattle would be used, as they are more docile.

“A lot of our neighbors are cattle ranchers and they’re hurting because of the tick. We want to try and help. Certainly, we have concerns, too, for the habitat,” Blihovde said.

But the proposals for cattle grazing and the use of insecticide-laced deer feed is not without its detractors. During a month-long public commenting period hosted by the USDA, dozens of concerned residents expressed staunch opposition to both.

One such person was Laguna Vista resident Nicole Eckstrom, who serves on the board of the Friends of Laguna Atascosa. “We are not in support. Our board is not in support of that,” Eckstrom said during a phone interview.

Eckstrom cited a lack of scientific data that examines how ivermectin treated corn would affect wildlife. She feared the refuge’s population of migratory birds could unwittingly ingest the chemical to detrimental effect.

“It’s been documented in other cases where these same feeders that birds definitely can get into it,” she said.

Blihovde said steps will be taken to mitigate any collateral impacts to other species. The feeders will be closely fenced. Access to the corn will be limited via a small hole that deer will have to stick their heads into.

“We’ve racked our brains trying to think of all the effects this could have on wildlife and we don’t think that there will be any deleterious effects,” Blihovde said.

Up to 100 feeders will be installed, which will be monitored weekly. That concerns Eckstrom, too, who fears that increased foot traffic in the refuge’s environmentally sensitive areas could cause damage.

As the commenting period came to a close late in January, the USDA deliberated the environmental assessment. Just last week, it issued a finding of “no significant impacts,” meaning the two tick eradication methods can go forward.

Blihovde said cattle could be brought to the refuge as soon as the end of the month.

But all the efforts could be for naught. Nilgai don’t exist solely on the refuge. Many of the exotic animals hide in the brush of nearby ranches and other private property. “The estimates we’ve seen from USDA are that there are more nilgai outside the refuge than there are inside the refuge. We may harvest a lot on the refuge and they kind of fill back in,” Blihovde explained.

Though the refuge will move forward with the treated corn and cattle grazing, officials are eager to explore other options to reduce nilgai and deer numbers, as well, the refuge manager explained. He said he hopes to be able to organize hunting opportunities for injured or wounded veterans via the Wounded Warrior program. Too, the Refuge recently announced the opening of two more public hunting opportunities from April 7-8 and April 14-15.

Blihovde is hopeful the combined efforts and methods of addressing the tick issue will be enough to eradicate them. “We hope that that would be enough to actually do what is necessary to get the ticks out of the environment because we definitely want to help and rid the area of this tick. It’s a nonnative tick, it’s not supposed to be here,” he said.

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