Dealing with Trap-Shy Rodents

Trap-shy rodents can create a variety of difficulties for pest management professionals. Timmy Madere, pest control specialist, New Orleans Mosquito, Rodent and Termite Control Board, shared his tips for dealing with trap-shy rodents during PCT’s 2019 Rodent Control Virtual Conference.

Madere said an important part of dealing with these rodents is understanding the difference between neophobia and trap shyness. To some extent, all rodents have neophobia, or a fear of anything new or unfamiliar. “It’s ingrained in them to be suspect of anything new that enters into their little worlds because every day they’re going out and they’re putting out pheromone markers in their urine and in their droppings or rub marks and are marking their world,” Madere said.

Unlike neophobia, trap shyness is a learned behavior, Madere said. When rodents interact with traps and don’t get caught, they develop a fear of them and understand to stay away in the future. Not only does this make it more difficult to catch rodents, but it’s also problematic because PMPs themselves are the ones teaching the behavior, Madere said.

“Every time you get a miss and not a kill on that trap, you’re creating a trap-shy rodent, which is going to be really hard to overcome,” Madere said.

However, PMPs can take several steps to avoid creating trap-shy rodents. Here are some of Madere’s recommendations.

EACH JOB’S DIFFERENT. Even if jobs seem routine, PMPs should approach them on a case-by-case basis. “You can take a long time to get things done depending on the scale where you’re working,” Madere said. “We can’t just go, ‘Well, I’ve seen it before.’” Pest behavior varies based on the environment, particularly among rats and mice. It’s important for PMPs to consider how these rodents may have adapted to certain aspects of their environment (e.g., weather) and use that knowledge to their advantage when trying to catch trap-shy rodents.

Timmy Madere

LOOK FOR DETAILS. With trap-shy rodents, PMPs need to focus on the details. One way they can do this is by looking for trails left by rodents when they travel. This approach may require more time and energy, but Madere said it can lead PMPs directly to the rodents. “I’m not saying it’s easy to get the rat in the trap,” Madere said, “but it’s easy to find out where they’re traveling, easy to find out where they’re hiding. And from there, we can get them.”

PRE-BAIT TRAPS. PMPs can conquer rodent problems more effectively by pre-baiting, Madere said. Pre-baiting occurs when a technician loads a trap but doesn’t immediately set it, and instead allows the rodent to feed off it for a period of time. As the rodent grows acquainted with the trap, it becomes less suspicious and easier to catch. “It is abundantly clear that this is not only going to improve your trap rate, it’s going improve the time it takes for you to get total control of this problem instead of taking months of chipping away [getting] one or two mice a week,” Madere said.

SELECT BAITS CAREFULLY. When selecting a bait, it’s important to consider a variety of factors, including environment and weather. Think about the types of food the rodent regularly eats and choose baits that cater to its dietary needs. For example, a rodent in an Italian restaurant might consume a lot of carbohydrates, so putting out salted meat might attract it because protein has been missing from its diet. Similarly, if it’s wintertime, using fruits and vegetables as baits may be effective because these foods are more difficult for rodents to obtain. If a rodent eats dry dog food, consider cucumbers or leafy spinach. These foods will give the rodent the moisture it likely craves. Ultimately, “it’s about being versatile because the animals we’re dealing with are extremely versatile,” Madere said.

UNFLAVORED GLUEBOARDS. Although many PMPs view peanut butter as a reliable rodent bait, Madere said it can become ineffective if it’s used repeatedly. Madere explained that the issue with using the same food over a long period of time is that it trains rodents to sense danger. “We’ve trained them and conditioned these animals to fear things that they traditionally love,” Madere said. Instead of using flavored glueboards, Madere recommends unflavored ones. He said this will help prevent rodents from becoming afraid of certain flavors and bait types.

PLACE TRAPS STRATEGICALLY. Although some PMPs may put down traps without carefully considering their placement, Madere said this practice can make their jobs more difficult in the long run. “We don’t realize by [placing traps] without any thought to where they’re going or what they’re baited with…we’re teaching animals to become trap-shy,” Madere said. It’s crucial for PMPs to think about where they’re putting traps instead of leaving them in random places. PMPs should also think about ways that rodents might be able to escape based on where a trap is located.

BE CREATIVE. Avoid using standard traps and baits because no two jobs will be identical. Different rodent populations have different experiences with traps. As a result, some will be afraid of certain traps, while others won’t possess those same fears. “They’re going to be different every time you get to them,” Madere said. “It’s never going to be standard.” By not setting standards, PMPs can equip themselves with many different approaches to solve rodent problems.

AN APPROPRIATE TRAP. Some PMPs may prefer one type of rat trap over another, but each one has its own specific purpose. “There’s no such thing as a bad rat trap,” Madere said. “Really, there’s just a bad situation for some of the traps. It’s all how you place and when you use them.” Madere explained that he uses different traps depending on whether the job is indoors or outdoors. Factors like humidity can make traps that are effective indoors ineffective outdoors.

USE AMBUSH BOXES. An effective way to trap rodents is to use ambush boxes, Madere said. These bait stations trap rodents by playing on their biology because they look like small spaces for them to hide. “We’re going to use biology against them because they’re prey animals...they want to get in the dark quick, especially if you’re in a warehouse or some very well-lit building,” Madere said. PMPs can put traps inside of cardboard boxes (i.e., Coca-Cola) to create this effect.

CONSIDER LIVE BAIT. Another option is using live bait to catch rodents. Madere said he and his colleagues recently started to notice that rats and mice feed on insects. “They like to eat [the] American cockroach, especially house mice, more than anything,” Madere said. Although he has only begun to explore this idea, Madere said he knows these rodents hunt insects. PMPs can use this knowledge in their efforts to catch elusive rodents.

USE DIRTY TRAPS. Madere said a common misconception is that rats will avoid traps that other rodents have been caught in. “My dirty stations tend to work better and get more rats,” Madere said. Rats cannibalize one another, so they may perceive the scent of another rat as food. Trap-shy rats might come out if they suspect an easy source of food could be available.

The author is an Ohio-based writer.