Curbstone Valley Farm: Got Gophers?

Dear Readers,
The kind folks at Curbstone Valley Farm posted this on their fine blog and website and allowed me to repost it. Enjoy!

Curbstone Valley Farm: Got Gophers?
***some images and video not for the faint-hearted***
We have pocket gophers. Lots of them. We try very hard not to interfere with native plant and animal species on the property. However, in the garden and orchard areas we occasionally find we need to address our pocket gopher population. Burgeoning populations can quickly decimate rows of crops, kill small shrubs and trees, and do significant damage to underground irrigation systems.



Valley Pocket Gopher - the mortal enemy of young fruit trees

When we first moved here it was clear that in some parts of the property we had a healthy pocket gopher population. We knew that some degree of effective gopher control would need to be employed to protect our investment of newly planted fruit trees in the orchard.
Our goal was not to eliminate all gophers from the property. That’s neither reasonable, nor desirable. Although pocket gophers are damaging to crops, they do have benefits. They bury organic matter in the soil, increasing soil fertility. They aerate soils, preventing compaction, and increasing water penetration, thereby decreasing run-off. Their burrow systems are often utilized by other species, including our resident Coast Range Newts, as valuable shelter from weather and predators. Gophers also help to increase the rate of soil formation by bringing subsoil materials to the surface, where they are subjected to weathering. A few gophers aren’t necessarily bad, we just want to prevent the population from getting out of control.


In addition to powerful jaws, pocket gophers have long sharp claws

Five species of pocket gophers are found in California. The Botta’s, or Valley Pocket Gopher, Thomomys bottae, is the most widely distributed in this state, and the species we have here. Various species of pocket gopher are found throughout the western two-thirds of the United States, and parts of the southeast.
Regardless as to species, they are all controlled similarly and there are numerous legal methods of gopher control. Popular control methods have included baiting with toxic baits such as Strychnine-treated grain, or anticoagulant rodenticides, or hiring a certified professional to fumigate with aluminum phosphide.
We weren’t interested in using any toxic methods of control, not just to protect our own animals, but also the wild birds and animals here, and to eliminate any risks of residue run-off into the two creeks on the property. We consider this property to be sensitive habitat for numerous native plant and animal species, and have no desire to risk their populations for the sake of controlling a few gophers.
Non-toxic methods of control include trapping, barrier-exclusion methods of control, such as lining garden beds with hardware cloth or gopher wire, wrapping root-balls of sensitive plants in gopher wire, and encouraging natural predators to assist us in keeping populations in check. In the non-cultivated areas of the property we rely on natural predators to keep pocket gopher populations down. Our resident hawks, owls, coyotes, and bobcats are all natural predators of gophers, as is this gopher snake. But honestly, how many gophers can a gopher snake eat in a year?


The Pacific Gopher Snake (Pituophis catenifer catenifer) can't eat enough gophers to control large populations

We caught this bobcat earlier this year catching a gopher, with a side of salad, near the chicken coop.
Video: Bobcat Catches a Gopher at Curbstone Valley Farm
Unfortunately, the bobcats can’t reach the gophers running amok in our fenced orchard, and even if they could, they don’t consume enough of them, often enough, to significantly affect their populations. That’s where trapping becomes our best option.
We’d tried Macabee traps previously, but we had very rare success using those traps.
Unfortunately, the bobcats can’t reach the gophers running amok in our fenced orchard, and even if they could, they don’t consume enough of them, often enough, to significantly affect their populations. That’s where trapping becomes our best option.
We’d tried Macabee traps previously, but we had very rare success using those traps.


Macabee Trap - 'Old Reliable'...wasn't. We had poor success with this time-consuming trapping method.

Our soils here are friable, and it’s difficult excavating down to a horizontal run to place pairs of traps, without collapsing the tunnels completely. Macabee traps also aren’t very humane. They impale the gopher, but they’re not instantly killed. They bleed to death, slowly.


Cinch traps are easier to use than Macabee traps, and a more humane method of trapping

We had tried Cinch Traps, and had even less success with those. They are more humane, as they instantly kill the gopher, breaking its neck. What we didn’t realize was there is an art, and a science, to using Cinch Traps correctly, and successfully. Fortunately for us, we have an excellent local resource available, Thomas Wittman.
Thomas owns and operates Gophers Limited, in Felton, California. He teaches farmers, grounds keepers, and individual gardeners how to evaluate and control their own gopher populations. Desperate to squash the gopher problem that was gnawing its way across our orchard slope, we spoke with Thomas about doing an on-site evaluation and personal training session to teach us what we were doing wrong, so we could effectively trap our gophers. Thomas however recommended that we begin with one of his ’starter kits’, which included two traps, a hori-hori knife, and an in-depth instructional DVD. If after watching the DVD we still weren’t successful at trapping gophers on the property, he’d be more than happy to set up a private consult.



Our starter kit included this instructional video

We purchased his ‘Cinch Method Starter Kit’, and watched the video. We learned a lot more about gophers than we realized there was to know, and finally understood why our previous trapping attempts had been met with such limited
success. Thomas taught us how to think more like a gopher, how to read important patterns in soil disturbances, and most importantly where to place the Cinch Trap, and how to properly set the trap for greatest success.
The next morning, eager to deploy our new found knowledge against the gophers that had previously outwitted us, we set two traps. Thomas demonstrates placing the Cinch Traps in this video excerpt.
Video: Gopher Trapping Using the Cinch Surface Method (see gopherslimited.com)

We didn’t expect to be as successful as Thomas is in this video, as we hadn’t caught a gopher ourselves in months, but before lunch, we’d caught our first TWO pocket gophers in the orchard. Thomas’ kit had already paid for itself as we now had finally caught the most problematic gophers threatening our new fruit trees. As our gophers are killed without toxins, rather than bury them, we leave them at the soil surface. There are plenty of predators and scavengers here, and by morning they’re always gone.


Our first catch of the day

Ever wonder why these little rodents are called pocketgophers? I’d never really thought about it before. Pocket gophers get their name from their extensive external cheek pouches. Fur-lined pockets that extend all the way back toward their shoulders. They can pack a lot of food into these pockets, and transport it through their burrows, leaving their teeth and claws free for digging.


Pocket gophers transport food in their extensive external cheek pockets


Turning out this gopher's pockets revealed an entire crimson clover seed head

We took a little video of our first two successful catches. The video starts with a gopher underground tugging on the roots of some weeds (you can see the plant ‘twitching’).
Video: Checking Gopher Cinch Traps at Curbstone Valley Farm
We don’t usually recommend specific products on our blog, but if you have a seemingly endless supply of gophers, and are interested in non-toxic control of your resident gopher population, we highly recommend Thomas Wittman’s DVD. It was a good investment for us, and we finally feel confident that we can keep our gophers under control. If you reside in the San Francisco Bay Area, Thomas also does presentations throughout the year, in various locations. See the Gophers Limited website for upcoming sessions.

Ground Squirrel Control Without Poison

Ground Squirrel Control Without Poison

I have spent a lot of time working with the California Ground Squirrel. This animal can be a great nuisance in any situation where the squirrels and people try to co-exist. There are some problems with digging under structures, digging large burrows that stock animals and children can trip in. But the major problem is the fact that they are community animals and therefore are vectors for diseases. Two in particular rabies and Bubonic Plague (there was a case of plague last year in Monterey County). This is mostly due to fleas. Animals that share burrows almost always have fleas. When it comes to school grounds and public areas the squirrels cannot be tolerated. In agriculture I have seen ground squirrels steal corn crops, nuts and damage many other crops. If you have them, you will need to eventually find a way to control populations or eliminate them as much as possible and keep breeding populations extremely low.

I have tried many traps, lethal and live and finally found a trap that works well enough to really help solve the problem without spending a lot of time at the job. This technique can be very useful for public areas and schools because the trap is used for a very short time after a period of pre baiting.



Instructions for the Black Fox repeating Ground Squirrel Trap

This trap is great for Ground Squirrels and Prairie Dogs. The action that is different from other live traps is that the Black Fox trap takes advantage of the social nature of these rodent species. Ground squirrels and Prairie dogs are always curious about new things in the environment and will avoid them until they are comfortable. These animals work as a social group. You will see one or two always watching and warning the colony of impending danger. They are always aware of what the other animals in the colony are doing. Because of this behavior the area where trapping is to be done needs to be pre baited and the trap needs to be locked closed during this period and present near the pre baiting area. I advise trappers to put bait out for 5-7 days and see when the animals are readily feeding and eating all the bait every day. You want to create a feeding frenzy, not adding too much food but enough so that you draw a crowd. The object is to catch most or the entire colony in one trapping session. On the seventh morning, if the animals are feeding readily, place the trap right on the bait pile and put some bait inside as well as scatter a small amount by the door openings. Try to be sure the trap is flat on the ground and if possible settle the trap so some soil covers the bottom wire of the trap. Open the two door covers and you are set. Try to get back to the trap by noon or so and you should have a good catch by then. If you don’t check on the trap in a few hours the animals will probably not survive in the trap. When you have a catch then you need to do something to the animals. Some farmers and ranchers drown them and others use a euthanization chamber . You can make this out of plywood or use any plastic container the trap will fit in. Here is a photo of one that works well. CO2 is the preferred gas but sometimes in the field auto exhaust is an OK substitute. kill boxThis box has one side that opens to slide the trap in and hole the size of a shop vac hose to connect to exhaust pipe. 5-7 minutes are usually enough, adding a Plexiglas window would be helpful.
Baits: red oats, bird food, dog food, chicken, french fries, apples, cabbage and greens, corn – you may have to experiment to find the right bait.

Why Poisons Are Not In My Bag For Gophers and Moles

Dear Readers,
Here is a recent letter a concerned parent sent me:
"Hi Mr. Wittman...I called you today in regards to my daughter's gopher problem in her suburban backyard in Danville, CA. A local pest company tried by putting strychnine granules in the tunnels only to have the gophers push it back out. Not a good answer to the problem since she has two toddlers who love their back yard. The kids were playing in the soft dirt and the green granules were in the soft dirt apparently not placed in the correct tunnels. Being a concerned grandmother, I'm all in favor of trapping the rodents while the kids are not home. The backyard has actually been off limits since this all became a very scary POISONED play yard. She has three of four new mounds a day."
This is not the first time I have heard of this and I know it won't be the last. I have heard many stories of birds eating poisoned grain and dying right on the lawn and many stories of pets and wildlife (especially owls) that have been poisoned by mistake. This is mostly due to a lack of understanding about the nature of the target animals and the poisons themselves.
Today, professionals usually use for gophers a tablet that turns into a gas called Phostoxin. When applied to a fresh gopher mound it is usually very effective. You need a license to apply it and the secondary or accidental kill rate is very low. The applicator is usually the one in danger but I have heard of accidental poisonings with this material also including the death of a child. But in terms of residual poison left in the ground, there is none.
Poisons that are available to non professionals, like strychnine and anticoagulants are much more dangerous to kids, pets and wildlife. First the strychnine baits are usually coated over seeds, usually milo, a common round bird seed and colored bright green or green blue. This seed flows easily from dispensers like funnels and poison metering probes. When put into a gopher tunnel it is usually fatal but sometimes the gopher pushes it back up out of the tunnel. When used for moles it is completely ineffective as moles or carnivores and do not eat seeds so they usually push it back to the surface. Birds are the ones who usually end up eating it but so do other seed eating mammals like mice, etcetera. But as in the letter above young children see it as candy and may eat it. So my advice is to stay away from poisons and especially strychnine.
Antocoagulants are the next most popular catagory and they are fatal only after the target animal eats the grain or raison coated bait for several days, allowing the poison to build up in the animals body until internal bleading causes death. Though not as dangerous to a non target animal ingesting one dose, this can be a problem when predators like hawks and owls eat the poisoned animal. There is a lot of documented evidence of secondary poisoning of wildlife.
So, I say trapping is the best strategy and I have developed methods that can be as effective or more effective than poisons. I offer this information to you on my website and can supply you with the tools to achieve gopher, mole and other small animal control easily and without endangering other animals, people or even our water sheds and marine environments.
Thanks for listening,
Thomas