Mole Control: DIY Trap Construction

Mole control methods range the gamut from simple and non-toxic to chemical-based and complex. My simple mole trap was founded on the basis of field trials and personal convictions I hold regarding the environment and its inhabitants. Prior research had been done early on in the search for a humane and sustainable method for dealing with the mole problem here at Highland Hill Farm.

Highland Hill Farm is a 22-acre parcel located in the steep, rocky foothills of Mt. Sunapee. Agriculturally speaking, this area of New Hampshire is better suited for grazing pasture and forestry than for large-scale horticulture. A milestone in sustainability and independence here on the farm has been reached with the addition of a fully functioning, off-grid solar powered electrical system. Photovoltaic solar panels supply clean renewable power to maintain three farmstead dwellings as well as the two large chest freezers used to keep the summer produce fresh. This system was designed, constructed and fully funded by myself as a personal goal to act responsibly in support of the convictions I maintain toward environmental stewardship.

This article was written on a computer powered by the sun. I developed and experimented with various types of mole traps. The soil of my growing beds is rich and teeming with life, especially earthworms, the favorite food of the common northern mole (Talpa europaea ). Over the years I’ve been using a thick layer of mulch hay between the rows and around the spring plantings. This layer of hay provides cover for the moles, and as it decomposes it provides food for the earthworms. Plenty of worms create an environment conducive to plenty of moles. It’s not uncommon for me to step on a mole tunnel every third or fourth step, even around the grassy area near the trout pond. The infestation had gotten to the point where action had to be taken.

Moles undermine the root systems of plants, damaging the plants and making irrigation and nutrient up-take much more difficult. I believe the live trapping methods I’ve been developing have merit in helping farmers eradicate moles in an environmentally sound way, without toxic poisons or mechanical traps. I will continue to develop inexpensive, effective live mole traps through field trials at various farm locations throughout the area. The opportunity to develop new methods and designs may have crossover potential for other rodent pests.

Poisonous Bait

The main thrust of the commercial market relating to rodent eradication is focused on poisonous bait. Motomco Mole Killer claims, “one worm contains a lethal dose.” Unfortunately, the poisoned mole may become the prey of another unintended victim of the poisoned bait. This product is “not to be sold in AK, HI, NC and NY.” Another poison-based product, Moletox claims, “This exclusive formula pelleted bait has a unique cracked corn base, making it more palatable.” The problem here is that moles are exclusively carnivores/insectivores and would have no interest in cracked corn. This product is “not to be sold in CA, IN, NC, NH and Washington D.C.”

Clearly poisons should be an absolute last resort rather than a first choice.

Mechanical Traps

Mechanical traps offer a considerable advantage over poisons as far as environmental impacts are concerned. Most mechanical mole traps are designed to either impale or squeeze a mole, one at a time rendering the trap ineffective until it gets reset.

These traps are spring-loaded and come with their own warnings. The “innovative new scissor trap” is not to be sold in Alaska, Hawaii or North Carolina. These traps must be set over an active mole tunnel (of which there are many to choose from) and require a lot of vigilance on the part of the trapper. Here the trapper is going to spend a considerable amount of time chasing the moles, hit or miss, around the field in order to eradicate but a few.

Mole Control: Organic Mole Eradication

I had been on the search for a natural or organic method of mole eradication and have viewed many websites in a quest for a somewhat humane mole trap. The “sticky” trap seemed the best, consisting of a wide tape-like sheet that the moles were supposed to get stuck to. I made one but caught none. I’ve discovered moles are quite clever — they will test something and if they don’t like it after trying it once, they’ll stay away from it. Besides, there was no incentive for the moles to cut across the sticky sheet, no food, no reward, just a shortcut.

The mulch hay I lay over the bare soil each spring protects the microbial life-forms on the soil surface from solar UV rays that would otherwise sterilize the soil surface, killing that rich, vibrant biomass. Nature does her best to cover over bare soil with biomass in order to protect soil life-forms to keep them alive, protected from UV and erosion-proof.

I like using the mulch hay method because it is constantly building soil. The hay method also prevents compaction because the weight of man or equipment is distributed over the wider surface area of a thick hay mat. The mulch also holds in a lot of otherwise evaporated water and prevents erosion during a downpour.

During midday if I pull back some of the hay, earthworms will be on the surface of the soil. Earthworm castings and the soil-enriching properties of their activity are beneficial to soil conditions and therefore beneficial to the crops that the soil supports.

If a farmer has a lot of earthworms and some loose hay on the ground chances are that he/she will also have a host of moles tunneling about. The benefits of using mulch hay far outweigh discontinuing the practice due to the mole problem, but they are a problem nonetheless. I was transplanting small lettuce plants from an outside raised bed into the winter greenhouse. The raised bed lettuce was riddled with sub-surface tunnels to the extent that I was able to remove large swaths of young plants simply by running my hands through the soil 2 to 3 inches under the surface, nearly unobstructed, plowing from one tunnel into the next.

This was an advantage in transplanting, but in my other greenhouse where spinach was planted in raised beds the plants were stunted and sparse because of mole activity. Mole activity necessitates more frequent watering due to the fact that sub-surface tunneling dries the soil much faster. Safely trapping and removing the moles from the greenhouses and growing beds will increase production of both crop plants and earthworm populations.

The trapping methods I’ve employed so far have consisted of several trap designs and various baits. One design in particular has shown promise over previous ideas. The primarily successful live trap now in place on my farm has trapped as many as four moles in the same trap over a three-day cycle, indicating that this method could potentially serve to trap many more live moles over a longer period, therefore alleviating the tedious chore of checking multiple mechanical traps every day or even every three or four days.

Moles consume nearly their own weight in food each day. Moles are from a group of mammals called insectivores. This live-capture study may also prove useful in that moles could possibly be used in areas of insect infestation to remove problem insects, then recaptured live and relocated for use at other sites.

Moles have several other distinct features that may prove useful in further studies. Moles produce a toxin in their saliva that incapacitates earthworms, and moles have a high blood oxygen content. I believe these two features of the anatomy of moles are worthy of a great deal of study. Live capture could possibly be a very positive offshoot of this live trapping method in order to supply research labs.

At this time live moles are released into the wild a fair distance from the trap locations. The experience of dealing with an infestation of destructive mole activity on my farm led to the search for a nonpoisonous, non-violent, inexpensive and effective method of eradicating moles.

Through my own experimentation and expressions of ideas I’ve come up with a mole trap that works reasonably well, has no environmentally harmful side effects and is economically viable for just about anyone, anywhere. The trapping method described has been put to use here over the last few months of this past growing season and I have documented its simplicity and effectiveness.

Mole Control: Preparing the Trap

This study was a comparison between the various trap designs that resulted from my experiment and used in combinations of live baits. No commercial traps or poisons were used. The best bait was local — earthworms on the farm were dug up and refrigerated for future use. The traps are simple to construct using a common 5-gallon pail that is clean and odor-free. A pail that has been open and set outside for a while or one used for garden water and soil will work well. Drill about 70 quarter-inch holes through the bottom to allow water to move through and to give the mole a sense of openness below.

Locate the area most heavily infested for installation. Dig a hole that will loosely accommodate the bucket with plenty of room around the sides to be backfilled with loose soil. Set the bucket in about 3 inches deeper than the bucket open top so that the fill soil slopes downward around the open rim. Now fill about 25 to 30 percent of the bucket with rich, loose soil. Get a separate container for your live worms and place just enough soil in to keep the worms alive but not allow escape. Six to eight worms are plenty and should last three to four days. Depress the worm container into the rich bucket soil to keep it at ground temperature and the worms alive. While installing your trap it is helpful to stand on top of boards in order to prevent compaction. Moles commonly reuse the same tunnels so try to leave them undisturbed. Place a generous layer of mulch hay around your trap and cover with a piece of board that has been outside for a while. Your trap is set.

If you leave the trap unchecked for three days you may have a better success rate than if you check more often. There will be less human presence sensed by the moles, and if there are some moles already in the trap, more are likely to join the festive party. Always wear gloves to prevent human odors around the trap and to protect your skin from wily moles.

The design intent for these trapping materials and methods involves materials that are available and common to most every area of the world. The design is simple to build and install at a very low cost to the farmer, involving no special tooling or hard-to-find materials. The design does not require the purchase of mechanical devices or commercial poisons.

The intent is to produce a replicable trap for mole control that can be constructed and installed by the average farmer using materials commonly found on any farm. Aspects of agricultural sustainability are addressed by the ability of the farmer to be able to build his own traps from simple materials and bait them with worms or insects that are found on the farm.

This study focused primarily on star-nosed moles and the European mole, also known as the common mole or northern mole, common to this Northeast region. Northeastern farmers who have mole infestation problems will most likely be dealing with these species, and the trapping methods should work equally well throughout the region and beyond. The simple trap designed and used here has proven to be successful in trapping moles. This method is easily transferable — the most successful design/bait combination is available to farmers everywhere. It seems likely this simple trap could work successfully for mole control most anywhere in the world.

By David Brown. This article was originally published in the September 2013 issue of Acres U.S.A. magazine.