TPWD research takes center stage in war on pigs

Published 12:35 am Saturday, January 27, 2018

In an effort to provide another tool in the control of wild pigs in Texas, the Texas Parks and Wildlife Department and its research partners are enlarging a project in hopes of gaining EPA approval for public use.

The project began in 2006 and is a follow-up to Australia’s use of sodium nitrite as a deadly bait for the wild pigs that some estimate cause more than $42 million in agricultural damage in Texas to just two crops — corn and sorghum.

This is the second time in less than 12 months the idea of a wild pig control bait has been considered in Texas. The first came with the support of Texas Department of Agriculture Commissioner Sid Miller, but was ultimately withdrawn after the manufacturer pulled its application for use in Texas because of a public and political outcry. That bait was a warfarin-based product based on a rat poison manufactured by Scimetrics Ltd.

Concerns ran from its impact on non-targeted species as well as how humane death was to the pigs. A bill was filed in the Texas legislature calling for instate research looking at the two issues, but Scimetrics pulled its application before action was taken on the bill.

In comparison, the sodium nitrite-based poison manufacturer, Animal Control Technologies Australia, in conjunction with TPWD, the U.S. Department of Agriculture, other researchers and private landowners, has already tested HOG-GONE under a number of scenarios.

Possibly as soon as February or March, the USDA’s Wildlife Services will begin EPA-mandated field tests on the bait on a ranch in Texas and property in Alabama. If it is successful and does not pose a threat to other wildlife, it could be available for use under controlled limits within two years.

The idea to test the bait got its start during a meeting at the Kerr Wildlife Management in which biologists were looking for wildlife research projects that would help Texans.

“It didn’t start with sodium nitrite or a toxicant. It started with myself and the team at the wildlife management area talking about things we should be working on to benefit people of this state,” explained TPWD research biologist John Foster.

That, of course, led to talking about wild pigs because of their negative impact in the state.

Foster began reading about methods being used around the world to control wild pig numbers with a focus on methods that are successful, cost effective, wildlife and environmentally friendly.

“The toxicants we looked at that were used worldwide, led to information that came out of Australia. They had pesticides already registered, some not registered and they were looking at new pesticides. What was really getting a lot of work done was sodium nitrite,” Foster said.

He said sodium nitrite had already proven itself as a good pesticide and had minimal impact on other species in Australia. The question was would it have the same impacts in the U.S.

“Sodium nitrite is very cheap. The questions were, is it lethal to pigs and can we deliver it to pigs and pigs only. We thought, yes we can because we are a bunch of smart people,” Foster said with a laugh.

Knowing it would work on pigs, TPWD’s staff and their partners started their research on sodium nitrite’s affect on white-tailed deer and raccoons. Deer were obvious because of their importance both socially and economically. Raccoons were tested because the researchers suspected they would be one of the species most likely to get into the bait if possible.

“What we learned was that raccoons were really sensitive to sodium nitrite compared to white-tailed deer and pigs,” Foster said.

Foster led another research project looking at sodium nitrite’s impact on turkey vultures that consumed a pig that had eaten the bait and died. Because of how sodium nitrite works, there was no impact on the birds.

However, the tests showed it could also be fatal to deer. That is where a host of other researchers were brought in to work on a delivery system that would be species-specific as well as a bait platform that was stable and attractive to the pigs.

“Sodium nitrite is not stable so you are not just going to be pouring it on the ground. It is odorless, but it tastes terrible,” Foster said.

Researchers developed a paste-like substance that includes the sodium nitrite and is attractive to the pigs.

They also developed a feeder called a Hog-Hopper that utilizes the pigs rooting habits, but is not accessible by most other species including javelina. The one drawback seems to be bears that can access the bait. This could limit its use in some southeastern states where bears and pigs coexist.

Foster said there are several differences between the sodium nitrite bait and the warfarin-based product, including that death is considered more humane from sodium nitrite because it is compared to carbon monoxide poisoning and happens more quickly. If approved for use in the field, landowners will not have to bury pig carcasses like they would have with the warfarin bait.

Foster said if the sodium nitrite bait does achieve EPA approval, it would not mean the end of wild pigs in Texas.

“We are so far past that. We are not going to wipe out pigs in Texas,” Foster said.

For one, landowners will have the option of using it or not. In Texas, there are landowners facing damage from the pigs while others sell hunts and benefit from them.

For those who do want to reduce numbers, it will be just another tool like aerial control, ground hunting and trapping.