Best practices
for nuisance wildlife control operators in New York State

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Ch 5: Step three: Do it - Nonlethal techniques

Frightening techniques and repellents

Repellents, you may remember from the earlier discussion, are objects, substances, or techniques that frighten an animal away. Or they make the desired object, such as a crop or nesting site, undesirable—the repellent may make that object smell or taste nasty, or feel bad to the touch.

There are several tools and techniques used to repel animals: scare devices; chemicals (which can only be used by NWCOs with a commercial pesticide applicator license); hazing with dogs, hawks, falcons, or radio-controlled boats and cars; and the use of guard animals.

Objects that look scary, such as mylar tape, strobe lights, lasers, models of predators, and "scare-eye" balloons, are often used to drive off birds. Geese and crows can be easily dispersed from a night-time roost by pointing a spotlight, laser pointer, or laser pistol (such as the Avian Dissauder®) at them. Visual repellents range dramatically in price, sophistication, and effectiveness. For example, everyone recognizes a scarecrow, but there are versions that actually move. These animated "human effigies" tend to work much better than the charming homemade kind, which are better considered as garden decorations. (Whenever possible, choose a repellent that moves, such as by swaying in the wind). Visual repellents should be clearly visible.

Objects that sound frightening, include a variety of firecracker-like noisemakers and recordings of distress calls and alarm calls. Sometimes, even banging a pot or rattling tin plates will drive off birds (but not ultrasonic devices, which they can't hear). Distress and alarm calls are most effective. Before using any noisemakers, check local ordinances and consider the effects on the neighbors. Fireworks-based noisemakers (a.k.a. "pyrotechnic devices") include

bangers (a.k.a. "bird bombs"): makes a loud bang. It's often launched from a handheld pistol launcher. Bangers can be used at medium range (50-100 feet).
screamers: makes a long, drawn out whistle. They can be launched from a handheld pistol launcher or a 12-gauge shotgun. The shell flies out about 100 feet, screaming and whistling all the way.
shell-crackers (or "crackers"): makes a loud bang that sounds like a M-80 firecracker. These shells are fired from a twelve-gauge shotgun, exploding about 75 yards away.
propane cannons: unlike the other devices, propane cannons can be used with a timer. All of the other devices must be fired by a person.

There are a few devices that combine flashing lights and scary noises, for example, the Critter Gitter®. Some of these can be very effective because they vary the pattern of the frightening element.

Chemicals that make objects smell, taste, or feel bad. You'd need a commercial pesticide applicator license to use any of these products in your NWCO business. For information about the training, contact the DEC's Bureau of Pesticide Management or Cornell's Pesticide Management Education Program.

Hazing describes a technique in which dogs, hawks, falcons, or radio-controlled aircraft and boats drive nuisance animals away from a site. Hazing Canada geese with border collies is one of the most effective ways to chase the birds away from golf courses, public parks, and similar locations. Hawks are sometimes used to chase other birds away from airport runways.

Don't haze birds in their nesting areas during the nesting season—that's a violation of the Migratory Bird Treaty Act. Be very careful if you want to haze Canada geese during their molt (usually June 15–July 15), because the geese are vulnerable and can't fly. It's wise to first secure a permit that would allow the taking of geese. Even a well-trained dog might accidentally injure a goose while chasing it. Without a permit, that's also a violation of the Migratory Bird Treaty Act.

Guard animals such as dogs and llamas are sometimes used to protect livestock, especially sheep, from predators. The livestock and the guard animal must be kept within a fenced area. Dogs can sometimes protect orchards or Christmas tree plantations or vineyards from deer or turkey damage.

You may encounter different definitions of "repellent" and "exclusion device." There is natural overlap between the two categories. Don't sweat it. We've classified products that are meant to be permanent installations, such as porcupine wire and post-and-grid systems, as exclusion devices. Although they repel birds, these devices are clearly barriers. Recordings of distress and alarm calls may have a long-lasting effect, but they are noisemakers.

Does this classification matter to anyone but an academic? Yes—because you need to remember that in general, repellents are a bit trickier to use. Although they may provide quick relief, it often doesn't last. Exclusion devices, on the other hand, often require an up-front investment because the materials and installation may be expensive. They tend to provide long-lasting results, and help to prevent problems. Exclusion can be a proactive approach, but repellents are generally a reactive strategy.

General tips for the use of repellents and frightening techniques

Before you use any repellents, double-check their legal status at all levels: federal, state, and local. Are you dealing with a protected species (usually, a migratory bird)? Any local ordinances that come into play? For example, noise ordinances would affect your ability to make use of pyrotechnic devices, which are purposefully loud. Local bird control ordinances might affect your choices, too.
If you want to use chemical repellents, you must follow pesticide regulations.
Often, a combination of techniques is more effective than using one technique by itself.
Repellents tend to be more successful in preventing new behavior (such as roosting, nesting, or feeding) than in stopping a well-established behavior.
Another thing to remember is that animals get used to both visual and sound repellents. To increase your chance of success, mix things up a little. Move the devices around. Change the patterns of the noise or lights. Keep it unpredictable.
Remove the devices after the problem has stopped (or if the animals have left the area for other reasons).

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