The Canada goose: A wildlife success story?
Did wildlife professionals do their job too well? Surprisingly to many Americans, Canada geese (Branta canadensis) were almost extirpated from most of North America by the beginning of the 20
Most of the problems caused by Canada geese are due to “urban” geese that are actually different subspecies than other migratory Canada geese. These urban or resident geese spend most or all of their life in urban or suburban environments. Golf-course managers, business managers and park superintendents spend a lot of time, money and effort to landscape their property, manage their turf and provide a pleasant atmosphere for themselves and their guests or patrons. However, geese can aggressively charge people and their pets and have been known to bite them. The accumulation of droppings is a common complaint about geese. Geese can also cause tremendous damage to lawns and landscape plants.
Why have geese become a problem?
Canada geese prefer to nest within 150 feet of water and with a clear surrounding view. Nesting females generally return to the same sites year after year and often near the area where they hatched. Depending on the geographic region, nesting begins in late February to early April. Male and female Canada geese will form pair bonds during their first winter and mate for life. While Canada geese do not breed until their third year, pairs of non-breeding geese will still return with others to the breeding grounds.
Canada geese are grazers and prefer open areas with fertilized, succulent grass. In some cases, geese can cause extensive turf damage from overgrazing or soil compaction. Resident geese have access to nearby agricultural areas all year round, increasing the potential for them to cause crop damage.
Conflicts between people and geese have grown as goose populations have increased. However, specific factors have made urban habitats attractive to geese. The new shoots in mowed, fertilized lawns are an attractive food source. Canada geese prefer open, grassy areas near or adjacent to water. Water provides geese with protection from predators, and open spaces allow geese to view the approach of potential predators. Thus, golf courses, parks and residential developments with stormwater catchment ponds are often ideal habitats for Canada geese.
While hunting has traditionally been the primary means of managing goose populations, resident geese are not subject to harvest because of firearm restrictions in populated areas. Plus, the lack of natural predators in urban areas further reduces the factors that would otherwise keep populations in check. The situation is compounded when people feed geese. If conditions are right, a pair of geese can become a hundred or more in a short time.
Canada geese, both resident and migratory, are protected by the Migratory Bird Treaty Act of 1918. This act made it illegal to harm, take or possess migratory birds, any parts of the bird, their nests or their eggs, except during the hunting season or by special permit. In addition to this act, state and local laws regulate various control techniques (such as harvest methods, approved repellents, etc.). It is your responsibility to know the laws in your area. You can call your local conservation officer, state natural resources agency or U.S. Department of Agriculture, Animal and Plant Health Inspection Service (USDA-APHIS) Wildlife Services office for regulations in your area.
For a successful management strategy, you need to consider the biology and behavior of geese. In other words, you must identify the environmental factors that make the area attractive to geese. One strategy would be to eliminate all food (lawns) and cover (water). In most cases, this is not a reasonable approach. However, certain techniques will make an area less attractive to geese. You should use several techniques in combination, as opposed to one. No “magic bullet” will solve your problem. Past research and case studies suggest these strategies:
Reduce the available food and eliminate or reduce the ability of geese to walk from the water to adjacent feeding areas.
Consider the timing of your actions. Goose behavior, and therefore damage, changes throughout the seasons.
Solicit public or neighborhood involvement. Many people enjoy feeding geese and any actions to decrease their presence may be negatively perceived.
Be aware of laws and regulations. These change over time, and violations may damage your reputation with the public or make authorities reluctant to issue you future permits.
Consider reducing geese, not eliminating them. Most successful plans aim to reduce goose numbers to a level tolerable by all stakeholders.
Be proactive. Many people wait until the problem is out of control before seeking help. If you have a few geese now, you can expect to have a lot of geese in the future.
Many techniques are available to minimize conflicts between geese and people. Some of these techniques require specialized training or licenses. Always seek the advice of a professional. Contact your state natural resources agency or USDA-APHIS Wildlife Services offices for more information. In most cases, these agencies will not solve your problem for you, but they can provide you with the most current information available or supply you with a list of licensed wildlife-control operators that provide services for a fee.
Below is a list of common practices used in an integrated wildlife-damage management plan. They are listed in order of the simplest to the most complex. Again, almost all situations require a combination of several of these techniques.
Do not feed geese. You will likely have to work with your patrons and neighbors in your community. Many problems began with people innocently feeding a few birds. Feeding concentrates geese in areas and may also reduce the effectiveness of other measures you take to minimize goose damage.
Reduce fertilizer use. Geese prefer fertilized grass to unfertilized grass.
Reduce lawn size. This minimizes foraging sites for geese. Some ground covers and grasses are less preferred than other plants (turf). However, be aware that geese will readily eat less palatable plants if there are no alternatives available.
Reduce or eliminate mowing. Geese have more difficulty locating new shoots in taller grass (more than 6 inches). Allowing the grass or other vegetation to grow tall around water bodies may also act as a vegetative barrier to geese or block their line of sight, which is their primary protection against predators.
Vegetative barriers. Geese prefer to walk from land into water. Establishing any type of a barrier that prevents geese from doing so will make the area less attractive to geese. Plant shrubs, hedges or other taller plants around or in the water. Choose plants that will exceed 30 inches in height and establish them in areas at least 20 to 30 feet wide. These plants physically impede the geese from moving to and from the water, minimize the availability of new grass shoots to the geese and block their line of sight, making it more difficult for geese to see potential predators approaching. Some restoration nurseries sell pond- or lake-edge enhancement systems that can act as a vegetative barrier for geese while still beautifying the landscape.
Barrier plantings will likely require protection from geese during establishment. Fencing or an overhead grid wire system (6-ft. spacing) can achieve this.
Rock barriers. Large boulders (more than 2 feet in diameter) placed along the shoreline may discourage goose use and access to grazing sites by making it difficult for geese to walk in and out of the water. Their effectiveness is improved when used in conjunction with vegetative barriers.
Fence barriers. Fences can prevent geese from walking into an area. Fences should be at least 30 inches tall and have openings no larger than 3 inches in diameter. Woven wire, chicken wire, picket fencing, plastic snow fencing and construction fencing are examples of effective materials. The effectiveness of fence barriers may be enhanced when used in conjunction with landscaping modifications (vegetative barriers, reducing lawn size, etc.). Landscaping adjacent to fences will also make it more aesthetically pleasing.
Repellents. A few chemical taste repellents are registered for Canada geese (typically using the active ingredients methyl anthranilate or anthraquinone). Some brands are registered for turf and others for water. Foggers are available for ponds. Though effective, repellents usually need to be reapplied to turf over time to remain active: rain may dissolve them and mowing will remove much of the repellent from the turf (see “Vertebrate pest controls,” page 38, for a list of repellents). Therefore, many turf managers reserve repellents for smaller, more highly visible areas. Whether the cost of treating larger turf areas with repellents is acceptable is a judgment you'll have to make for your particular site. Remember, repellents are designed to deter geese from feeding on turf, not to physically exclude them from an area.
Be sure to read and follow the label of any repellent product you use. The chemicals noted above are not highly toxic to aquatic life but should only be applied in accordance with label directions to keep environmental effects minimal.
Hazing. Noisemaking devices (cracker shells, propane cannons, whistles, etc.) or visual deterrents (Mylar tape, etc.) can help deter geese from an area when used in conjunction with the habitat modification techniques listed above. If you use hazing alone, the geese will become habituated to it. Effective visual deterrents such as Mylar tape have movement and are metallic in appearance. Many noisemaking devices require a permit or license, especially within city limits. Some of these devices are classified as firearms in many areas.
Dogs. Border collies and other breeds can be effective in chasing geese. This is a culturally acceptable method to many, but requires a substantial monetary investment. These dogs require extensive training and must be kept active. The use of dogs has failed in the past when improperly trained dogs were used or a single dog was used for a small area. Sharing a dog among businesses can minimize the cost of training and boarding a dog. This also keeps the dog chasing geese more frequently. Check local regulations to see if leash laws might restrict the use of dogs.
Egg destruction. It is illegal to harass geese while they have eggs in the nest. However, you can apply for a permit from the U.S. Fish and Wildlife Service to destroy the eggs of Canada geese. In some states, the U.S. Fish and Wildlife Service may have authorized the state natural resources agency to issue goose-egg destruction permits. The eggs are rendered infertile by puncturing a small hole in each of them, shaking them or lightly covering them in oil. The eggs will not hatch, but the geese will continue to incubate them. This is important because removing the eggs may prompt geese to lay another clutch.
Bird removal. Geese, like all waterfowl, completely replace (or molt) their primary wing feathers at once and become flightless for about a month. The molting period typically begins in early June. You can “round-up” the geese at this time and relocate them. This is a costly and time-consuming process that you should use only when all other efforts have failed. Capturing and relocating geese requires federal and state permits. Past success of this method has varied. In some cases, the geese return the next year; in others, they do not. You will still need to make the environment less attractive to geese using some of the techniques listed above.
It is best to use preventive techniques before geese become established. Once geese are established, it can become difficult and expensive to exclude them from a given area, particularly after nesting has begun. Also, you should think long-term. For example, it will likely take several years for your vegetation barrier to mature and become established. Before this time, the vegetation barrier will not be an effective deterrent to geese. In fact, you may have to physically exclude geese from the area because the young, nutritious plants and shoots will likely be an attractive food source for geese.
Brian MacGowan is an Extension Wildlife Specialist with the Department of Forestry & Natural Resources, Purdue University (W. Lafayette, Ind.) and is a Certified Associate Wildlife Biologist.
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