In fact, there are a lot of them. Some work better than others. As with all hazing type repellents, their effectiveness is contingent on your persistence. Migratory geese are much easier to move off a site than resident geese. Resident geese have claimed the site as their home, and it is difficult to move them. Once the geese have begun to nest, repellents lose a significant amount of their effectiveness.

Waterfowl might be repelled by almost any large foreign object or mechanical noise-making device placed in a field. The length of time frightening devices are effective depends on the nature, number, and variety of devices used. Move frightening devices daily, and use them in varying combinations to improve efficacy and prevent habituation.

Repellents should be in place before the start of the damage season to prevent waterfowl from establishing a use pattern.

Visual repellents such as flags, balloons, and scarecrows should be reinforced with audio repellents such as automatic exploders, pyrotechnics, or distress calls for optimum results.

All applicable state and local laws must be observed when using frightening devices. Pay particular attention to laws governing the making of loud noises, discharging of firearms, use of pyrotechnics, and use of free-running dogs. Also consider the possible reaction of neighbors.

Flags for repelling waterfowl can be made with 4-foot (1.2-m) laths and 6 x 30-inch (15 x 76-cm) strips of 3-mil safety orange plastic or red and silver mylar ribbon. Tests conducted at Audubon National Wildlife Refuge indicate that black flags are not effective. Place flags so they are visible by waterfowl from all points in a field. Waterfowl will land in an area where flags are not visible. Once the birds land in a field with flags and begin feeding, the flags’ effectiveness may be lost. If birds access a site by swimming or walking, visual repellents are much less effective.

Balloons filled with helium, staked in open fields or over water, have proven to be effective waterfowl repellents. Tether the balloons with enough 75-pound (34-kg) test monofilament line to allow them to rise at least 10 feet (3 m) into the air. The use of balloons larger than 2 feet (0.6 m) in diameter is not recommended due to their increased wind resistance. Balloons with large contrasting eye spots seem more effective than balloons without eye spots.

Scarecrows can be made out of almost any material available. Three concepts should be incorporated into any scarecrow design: movement, bright colors, and large eyes. For maximum effect, the arms and legs should readily move in the wind. Construction materials should be of bright colors such as red, blaze orange, or safety yellow. Research indicates that scarecrows with large eyes are more effective than scarecrows with small eyes.

Mylar tape, 1/2 inch (11 mm) wide, has been used successfully to protect lawns, crops, and other areas from bird damage. When properly installed, mylar tape combines three control strategies in one—overhead grids, sound repellents, and visual repellents. Wind blowing over the tape will produce a roaring sound as the tape twists and flashes, reflecting the sunlight. Install the tape 1 to 3 feet (0.3 to 1 m) above the area to be protected on 6- to 30-foot (2- to 10-m) centers. For a 100-foot (30-m) span, the tape should be twisted no more than four or five times before tying it off. Over-twisting will reduce the flashing and roaring effect. Mylar tape has a tendency to break at the knot. This can be overcome by covering the last foot (0.3 m) of the mylar with nylon strapping tape before tying it off.

Water spray devices, using high pressure, rotating, clapper-type sprinkler heads have been used to repel other bird species from reservoirs and fish raceways. Gulls have been repelled from drinking water reservoirs by covering 50% of the total water surface with the sprinklers and cycling them on and off (5 minutes on and 35 to 45 minutes off) during the daylight hours. Similar methodology may be effective against waterfowl.

Automatic exploders, also known as propane cannons, make a loud noise without discharging a projectile. One exploder may protect up to 25 acres (10 ha) under ideal conditions. The rate of firing is manually adjustable; exploders should be set to fire about every 5 to 10 minutes. Reduce waterfowl habituation and increase the effectiveness of exploders by mounting them on turntables so the cannon rotates a few degrees with each firing. Turn exploders off after dusk and on at dawn to reduce neighbor complaints and bird habituation and to save on fuel. Clock timers or photocells are available for this purpose.

Waterfowl may use fields on bright moonlit nights. When they do, it may be desirable to run exploders all night. However, geese often habituate to propane cannons on a timer.

Pyrotechnics such as shellcrackers, whistle bombs, screamer/banger rockets, and noise bombs can be used to repel waterfowl. These devices should be fired to explode in the air just over the birds to produce the greatest scaring effect and reduce the fire hazard. Allowing pyrotechnics to explode on the ground could ignite dry grass or weeds.

Recorded distress calls have been used to repel several species of nuisance birds. Canada goose distress call tapes are not commercially available as of this writing. Individuals have made their own Canada goose distress call recordings and have successfully repelled nuisance geese. Ultrasound will not repel geese.

Remote controlled boats are very effective when used to haze geese (without goslings) in the water.

Specially trained dogs can be used quite successfully to harass geese. It is recommended that they always be under the control of a knowledgeable handler.

Laser pointers and handheld spotlights have also been successfully used to haze geese at night when they are roosting. Use caution with lasers as they can damage the user's eyes.

Resources: (online)
Waterfowl Control Information

Goose Control Information