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> RODENTS
USE THE RIGHT CONTROL TOOLS
Bubble gum and gasoline might sound like intriguing solutions to gopher problems, but other methods are cheaper and more effective, says a wildlife expert at Montana State University.
And by the way, if you think you're overrun with gophers, you're more likely seeing ground squirrels. It's important to know the difference, because you have to handle them differently if you want to control them, said Jim Knight, Extension Wildlife Specialist. Strychnine is legal for pocket gophers, but illegal for ground squirrels.
"Ground squirrels are not gophers, but they are commonly called gophers in Montana," Knight said.
True gophers in Montana are actually pocket gophers, Knight said. They spend 99 percent of their time underground and look like rats. Their front teeth rest outside of their lips. They have small eyes, big digging claws, cheek pouches and a short tail. They are rarely found more than one to an acre.
Ground squirrels, on the other hand, are gregarious. They live in tunnels, look more like squirrels than rats and have significant tails. Every year, they're responsible for more than $7 million loss to Montana's alfalfa growers alone.
"Ground squirrel control is very necessary," Knight said.
Since pocket gophers spend most of their time underground, one way they can be controlled is with strychnine. The poison is placed underground. Gophers that eat it usually die underground.
Ground squirrels require a different approach, Knight said.
Gallatin County Extension Agent Ron Carlstrom wrote in his April newsletter that, "Uses of strychnine baits for ground squirrel and prairie dog control is an illegal and unregistered use."
Zinc phosphide is legal and kills ground squirrels with one lethal dose, Knight said. However, ground squirrels don't like the taste. They won't eat it unless it's early in the spring and they have nothing else to eat or they've been tricked. Knight suggested setting out regular non-treated oats first. Then, after the ground squirrels know they like it, substitute oats that have been treated with zinc phosphide.
"They only need a mouthful or two, and they will die," Knight said.
Rozol, an anticoagulant bait, also works well and ground squirrels like the taste, Knight said. Ground squirrels have to eat it for a couple of days so it builds up in their systems. They die from internal bleeding.
Zinc phosphide and Rozol are generally used on large-scale operations and can only be sold to licensed applicators, Knight said.
For the average property owner, Knight recommended placing a general-use anticoagulant rodenticide called Ramik-Green in bait stations. One station that works well and can be made from parts available at any plumbing supply store looks like an inverted T and is made from three- or four-inch PVC pipe. The arms of the T rest on the ground, and the stem stands upright. Knight suggested tying the stem to a fence post so it won't tip over. Fill the stem with anticoagulant bait and cover it with a lid so the poison won't get wet. Ground squirrels find the bait by running into the arms of the T.
Knight advised placing a PVC bait station every 50 yards along the perimeter of a field and keeping it filled with Ramik-Green. Leave the bait stations out the entire summer.
Most ground squirrels that die from anticoagulants generally die underground, Knight said. If they die above ground, they should be removed.
Non-target animals are often a concern, and anticoagulant baits are generally safer than other types of bait, Knight said. Although a single mouthful of strychnine could kill any animal, several feedings of anticoagulant bait is necessary for it to kill. Birds scavenging on dead ground squirrels would have to eat a few grains of anticoagulant over a few days, not just the meat of a poisoned ground squirrel, to die, Knight said. Birds generally don't eat the stomach.
As far as other controls go, Knight said bubble gum might sometimes clog a ground squirrel's intestines or burst its stomach, but no one has conducted scientific studies on its overall effectiveness. It's hardly cheap, he said. Neither is gasoline.
Knight wondered why people go to all the work of using such methods when controls like the ones he suggested typically work to reduce the population by 90 percent.
Some people have great fun shooting ground squirrels, Knight said. He doesn't deny they kill animals, but said shooting doesn't control populations.
"For every adult you kill, you have allowed a tunnel to be vacant," he said.
An empty tunnel means a new home and safer life for young ground squirrels who are kicked out of their old homes by adult ground squirrels.
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