Wildlife management activities related to crops can be a complicated matter due to the diversity of species, habitats, laws, and experience level of those facing damage. Avian and mammalian species can cause significant crop damage — which includes sweet corn — and management activities differ within species of both groups. Most avian species are governed by the U.S. Fish and Wildlife Services and are under federal protection. Whereas mammalian species are primarily managed by state agencies. The focus of this article will be mammalian species and how to help reduce damage they may cause.
Although exclusion and harassment are both very effective methods in reducing damage from mammal species, lethal control activities are often necessary to help enforce non-lethal practices and further reduce damage. Both exclusion and harassment are legal means and can be conducted without a permit or authorization from the regulatory agency. Lethal measures may be conducted, but prior to taking action it is important to determine the methods and other restrictions for your area. The best way to do this is to contact the local wildlife conservation/protection officer and have them visit your property and provide site specific authorization.
One of the primary ways to reduce damage to sweet corn is through exclusion. This is especially true when dealing with mammal species (white-tailed deer, black bears, raccoons, wild hogs, and other primarily terrestrial species). The main method of exclusion is fencing, with electrified fencing being the most effective tool. Although this may seem like a time consuming and expensive technique, there are many advantages to installing a temporary electric fence. The first is that this tool can work 24 hours a day, with minimal maintenance. It works on many species, and depending on design, it can be used seasonally. In addition, the fence can be reconstructed annually.
The most effective type of electric fence is multiple braided wire, going from ground level to 5 to 6 feet high. Although species such as deer can jump over a fence of this height, it will help reduce the number of animals that can easily enter the fields. Increased weaves of wire toward the base of the fencing will help reduce access to species like raccoons, groundhogs, opossums, black bears, and deer, especially younger animals that may not be able to jump over the fencing.
Installation of a solar powered charger and batteries will prevent the need to have power to the site, making the system more mobile so that it can be used on different fields. Fencing may not be required during the entire growing cycle of the corn, but only when damage is observed or crops are most vulnerable. If crops are staggered so they can be harvested throughout the summer, the same fence may be able to be moved between the fields to protect them when they are vulnerable.
It is important to monitor fences to ensure they are in good condition throughout the season, have not been damaged, and the power source is working correctly. Habitat management around fields can be beneficial in reducing damage to sweet corn. Removal of attractive habitat and refuge near fields is helpful and includes brush piles, rock-piles, old buildings, and vegetation adjacent to the fields. These features allow wildlife, especially small mammal species, refuge close to the food source.
Deter Through Harassment
Many harassment tools can be used to deter wildlife from using crops as a food source. Many larger property owners have employed propane cannons as a tool. These are propane-powered noise making devices that can be moved around the field interior. They are very loud and can be heard from more than a mile away. Other harassment devices include sirens, lights, and effigies, or decoys. These all can be effective tools for short-term harassment. One key is to use them on a limited basis and move the devices around the field. Wildlife can get accustomed to these techniques and they will quickly become ineffective. Even propane cannons will cease to deter wildlife from using fields.
The combination of harassment with exclusion can be very beneficial and significantly increase the effectiveness of the techniques. These methods can also be effective with reducing avian damage, and this is often how they are used, with effect on mammals an additional benefit. One drawback to harassment is that it can be time consuming. The most effective harassment is conducted while animals are using the resource. The need to move the devices around the affected area, as well as turning them on and off will take time during each day.
Wildlife management can be a complicated activity to attempt without professional guidance on techniques and laws. It is best to first research the management methods that you are considering, consult with a damage management expert, and visit with local wildlife law enforcement prior to the employment of any techniques. It is also important to remember that multiple management methods can be employed together to help reduce damage threats. With dealing with mammal damage, unlike problems with birds, local population management even if conducted outside the growing season can be effective in reducing damage.