Geese, ducks, and swans have always been a treasured natural resource in Pennsylvania. These birds are enjoyed by millions of people each year, whether they are birdwatchers, hunters, or just those who appreciate their presence. The fall flights of geese and swans in their characteristic “V”-flock formation are familiar and welcome signs of the changing seasons. However, because of recent dramatic increases in waterfowl populations, these birds have become a nuisance in some places. A lack of predators, decreased opportunities for waterfowl hunting, food handouts, and landscapes consisting of large expanses of turfgrass have provided ideal conditions for these birds.
Although most people find a few ducks or geese acceptable, waterfowl populations can quickly get out of hand. For example, one pair of geese can, in five to seven years, easily become 50 to 100 birds that foul ponds and damage lawns, golf courses, and crops. This fact sheet provides information on controlling damage caused by Canada Canada geese, ducks, and swans.
Canada geese mate for life, with both parents caring for, and aggressively protecting, their young. Canada geese in Pennsylvania consist of both migratory and nonmigratory populations. Migratory populations are the Atlantic Population and the Southern James Bay Population. These two populations nest in Canada and migrate south for the winter. Adults of both populations do not breed until three years of age. Both of these migratory populations have declined in size because of poor survival and low reproduction since 1985.
By contrast, the nonmigratory, or resident, population in Pennsylvania has grown from approximately 2,400 from 1955-60 to more than 150,000 in 1993. Adults in this population can begin breeding at age two and have a higher survival rate than migrating birds. The resident population consists of nonmigratory birds that nest and reside in the Mid-Atlantic states, including Pennsylvania, throughout the year. Because harvest restrictions that protect the migratory populations also have protected the resident population, Pennsylvania has recently established special hunting seasons to target the resident population of geese. These seasons take place when migrant populations are not in the state.
Canada geese may be discouraged from using ponds by installing a 30- to 36-inch-high poultry-wire fence at the water’s edge. This technique, however, is not effective for ducks. Three-foot-high woven-wire fences around gardens and yards also will help keep geese out of these places because adult geese with young will not cross a fence and leave their young behind. Geese also are reluctant to pass under a wire fence, so installing a single-strand fence, or one made of Mylar flashing tape, at a height of about 15 inches may discourage geese from entering an area. A 2-to 3-strand goose-resistant fence can be placed around lawns, gardens, and crop areas. Place the first strand 1 foot above the ground, with each succeeding strand 1.5 feet
above the previous strand. Snow drift fences and electric livestock fences have also proven effective.
Good results also have been reported using 20-pound test, or heavier, monofilament line to make a 2- to 3-strand fence in situations where aesthetics preclude the use of wire fencing. String the first line 6 inches off the ground, with each additional line spaced 6 inches above the preceding line. Suspend thin strips of aluminum foil at 3- to 6-foot intervals along the lines to increase visibility of the barrier for wildlife and people. The best results are obtained when the fence is in place before geese start grazing.
To stop waterfowl from using reservoirs, lakes, ponds, and fish-rearing facilities, overhead grids can be constructed of thin cable visible to both humans and waterfowl. White or brightly colored cables may improve visibility. Because these materials are extremely light, several hundred feet can be supported between two standard, 5-foot, steel fence posts. Grids on 20-foot centers will stop geese, and grids on 10-foot centers will stop most ducks. Where necessary, grid lines should be installed high enough to allow people and equipment to move beneath them. Excessive rubbing will result in line breakage, so grid wires should be tied together
wherever two lines cross.
Attach lines independently to each post and not in a constant run, to prevent having to rebuild the entire grid if a line breaks. Where total exclusion is needed, use 1- to 1.5-inch mesh polypropylene UV-protected netting. Support the netting with at least 0.19-inch, 7 x 19-strand galvanized coated cable on 20-foot centers. Support cables must be well anchored to carry the weight of the netting and to allow the cable to be stretched tight to eliminate sag. High winds are the greatest hazard to this type of netting installation, so netting should be attached to the support cables to prevent wind-caused abrasion.