Alternatives to Anticoagulant Poisons
For the sake of native wildlife, please use alternatives to rat poisons. Integrated pest management is an excellent alternative to poison use. Replacing anticoagulant rat poisons with another poison often will not reduce the risk of wildlife exposure to the poisons because no poisons available on the market in the U.S. have zero risk of unintended consequences for wildlife.
The best pest control practices include rodent-proofing human structures and encouraging natural predators. To encourage natural predators, nesting boxes and perches for owls can be installed around your homes (see HungryOwl for more information).
Preventative action is critical. Rodent-proof your homes by sealing holes. Remove unnecessary vegetation and trash in your yard that could be homes for rodents and other small mammals. If mice, rats, and ground squirrels are a problem around your home or business, remove food and water sources such as bird feeders and baths!
Finally, once you’ve taken the above steps, try mechanical traps. Wooden snap traps and electric zappers are good for within home use. Be careful when using traps outdoors so that other wildlife, such as raccoons, opossums, owls or other birds, are not unintentionally captured and injured. Pets can also fall victim to snap traps.
Rats and Mice
The rats and mice that people target in southern California may be both native and nonnative rats and mice. The most frequent chemical method of rodent control used worldwide is anticoagulant rodenticides. However, we recommend NOT using any poisons at all! Whether you use the poisons inside your home only, or both in and outdoors, you put other wildlife at risk of being poisoned too. Pets and children are not immune to the effects of these poisons either.
Are there safer, effective ways to control rats and mice?
- Seal holes inside and outside buildings to prevent entry by rats and mice.
- Keep areas clean and free of crumbs and water. Seal food in rodent-proof containers.
- Use snap-traps instead of baits whenever possible. Keep the traps indoor where wildlife such as raccoons, coyotes, opossums, etc. won't become accidental victims of the traps.
Within the southern California area, a lot of people consider our native pocket gophers a big problem around their gardens and lawns. Pocket gophers are strictly herbivorous, and will often pull plants into the ground by the roots to consume them in the safety of their burrows, where they spends 90% of their lives. The burrows of this species may reach lengths of more than 150 meters. The main predators of pocket gophers include badgers, coyotes, long-tailed weasels, bobcats, snakes, skunks, owls, and hawks. Despite their many predators, they are frequent targets of poisoning, particularly with the use of anticoagulant rodenticides.
Once you become aware of unwanted gopher activity, it is important to act quickly. Once a tunnel system is in place, other gophers can quickly replace any you may drive away. Various methods can help to repel gophers, but very few are foolproof. Some plants such as gopher spurge (Euphorbia lathyrus) and castor bean (Ricinus communis) have been reported to deter gophers because they exude a poisonous substance from their roots. Research shows that neither of these are consistently effective repellents. Putting substances in gopher tunnels -- used kitty litter, rags soaked in predator urine or pine oil -- works for some gardeners. Ultrasonic noisemakers provide only short-term relief.
The most effective controls are exclusion and trapping. In small beds, gardeners can create cages or baskets to protect prized plants. Dig a 2- to 3-foot-deep hole in the planting area and line the sides and bottom of the hole with wire mesh. Replace the soil and plant your garden. Protect trees with wire mesh guards placed a few inches below the soil line and 2 feet up the trunk. If need be, use traps to kill problem gophers.
The use of poisons, particularly anticoagulant rodenticides, is not recommended, no matter how bad the problem! Gophers do not necessarily die in their burrows, and anticoagulant rodenticides can take up to 10 days to kill an animal once it has ingested a lethal dose of the poisons. Thus, predatory animals can easily be exposed to the poisons by preying on already poisoned (but not yet dead) gophers. There is little evidence that poisoned gophers remain in their burrows when they die from poisoning.
If you are interested in traps, click here to learn more about those options.