Gettin' Gophers

Even though it's summer, the little ground rats are taking down some of my plants. So, a different look than previous posts on killin' gophers.

I’ve had good results with the “California box trap”. I think the box trap is easier to use if you’ve never set gopher traps before. The box trap in the photo here shows the installation, but the trigger has been activated – see the wire in the up position. [The gopher from the same trap pictured above would fill the entire box!]

To set the box traps, locate the main tunnel with a probe. I use a 24” piece of rebar. The permanent or main burrow [as opposed to the feeding runs] can be found by probing about eight to 12 inches from the plug side of the visible mound and is usually located six to 12 inches deep. When the probe penetrates the gopher’s burrow, there will be a sudden, noticeable drop of about two inches. You may have to probe repeatedly to locate the gopher’s main burrow, but your skill will improve with experience.

Use a shovel or garden trowel to open the tunnel wide enough to set traps in pairs facing opposite directions. By placing traps with their openings facing in opposite directions, a gopher coming from either end of the burrow can be intercepted.

Box traps are especially useful when the diameter of the gopher’s main burrow is small (less than three inches.)

Some claim it is a good idea to use lettuce, carrots, apples, alfalfa greens, or a drop of anise oil as bait. I rub all surfaces I’ve touched with grass or weeds and be sure to rub the trap trigger. [Or, use hospital disposable gloves.] Then I leave a piece of grass or whatever then it has been eating behind the trap’s wire.

After setting the traps, exclude light from the burrow by covering the opening with dirt clods, sod, cardboard, or some other material. Fine soil can be sifted around the edges to ensure a light-tight seal. If too much light enters, the gopher may plug the burrow with soil, filling the traps and making them ineffective. I place a large piece of plywood or cardboard over the entire “excavation” to make sure no light gets through.

The theory is that the gopher feels the flow of air and wants to plug the breach of the tunnel system. The gopher runs through the tunnel and is in the box before it knows it because the flashing on top of the box excludes light but allows air to escape.

Check traps often and reset them when necessary. If a gopher is not caught within 24 hours, reset the traps in a different location.

This is adapted, in part, from: Publication 7433, University of California Agriculture and Natural Resources. Revised January 2002.

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Go Pher Them

Pocket gophers, with Botta's pocket gopher (Thomomys bottae) being most widespread of the five species found in California, are a gardener’s the greatest fear in the west. [Those who garden east of the Mississippi river are free of these elusive pests.] When the Russians settled just north of Santa Rosa on the coast in 1812, the story goes “we could have made a good living if it weren’t for the land rats”.

These pesky critters are burrowing rodents that get their name from the fur-lined external cheek pouches, or pockets, that they use for carrying, and short fur that doesn't cake in wet soils they dig and tunnel constantly. If they don’t constantly make tunnels their teeth will curl up toward the brain and pierce it.

They spend a lot of time on the surface at night and are the prey of barn owls. Many vineyards, in their futile attempt to appear environmentalists, build barn owl boxes. They don’t know that the great-horned has a territory of up to ¼ of a mile from its nest. The one near my house and next to a vineyard, has this large predation area and keeps out the barn owls. Ever year I hear the great-horned owl gradually find each other for mating with hours of hooting. The vineyard is 100 feet from my house. Not many barn owls near me. Furthermore, the usual diet for a barn owl eats only one gopher each night. Thus, the gardeners in my area have resort to trapping (killing) these “ground rats”.

Unlike moles, gophers “throws” or mounds are crescent- or horseshoe-shaped when viewed from above. [See the left photo.] Mole mounds appear circular and have a plug in the middle is more likely volcano-shaped. Unlike gophers, moles leave a raised ridge to mark their path. Also, moles are carnivores and gophers are vegetarians.

Pocket gophers live in a burrow system that can cover an area of 200 to 2,000 square feet. Feeding burrows are 6 to 12 inches below ground, whereas they nest and food storage chamber that may be as deep as 6 feet. [I’ve dug into food stashes of dozens of gnawed carrots.] Gophers seal the openings to the burrow system with earthen plugs. Short, sloping lateral tunnels connect the main burrow system to the surface and are created during construction of the main tunnel for pushing dirt to the surface.

The University of New Mexico says “… [gophers] may occur in densities of up to 16 to 20 per acre”. Ha! They’ve never been in my garden!

So, trapping is a must. The other photo is a eight-inch long gopher caught in a California box trap. These ingenious traps worked on the fact that gophers maintain their main “highways” six to 12 inches below the surface, not the surface feeding tunnels. If the trap is put in the main run with the metal strip on the top-rear of the box slightly raised and all sides covered with dirt. This allows air to escape but excludes light. Usually the gopher wants to protect its main “highway” when it feels air rushing out. Running toward the open hole, the gopher is in the trap before it knows it because there is no light to give it a clue as to the breach of the tunnel. Gotcha!

Please post a comment - I want to know what you think.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert