SOUTH PORTLAND — Harassing ducks and geese with a remote-controlled mini airboat is one of several recommended techniques that city officials are considering to deter waterfowl whose droppings cover wide swaths of Mill Creek Park.

Installing fencing around Mill Creek Pond and treating grass with a goose repellent are two other methods suggested by a wildlife expert with the U.S. Department of Agriculture who met with city officials this month.

The wildlife expert also offered other options that likely would provide little relief from the 2 pounds of waste produced daily by each of about 200 mallard ducks and Canada geese that live in and around the 10-acre park.

The list of possibilities includes motion-activated sprinklers or alarms, air horns and other noise makers, predator decoys, reflective streamers or pinwheels, dogs trained to harass waterfowl and handheld bird-deterrent lasers.

Geese and ducks swim at Mill Creek Park in South Portland. Federal wildlife officials have suggested options for the city to consider to mitigate its problem with waste from the waterfowl. Derek Davis/Staff Photographer

Kristina Ertzner, conservation manager in the city’s parks department, immediately dismissed the laser option.

“Handheld lasers? We’re close to an airport – is that even legal? I don’t think so,” Ertzner said, referring to the Portland International Jetport, just across the Fore River. It is a federal crime to aim a laser pointer at an aircraft.

Ertzner is responding to residents’ complaints that accumulating waterfowl waste has turned the popular park into an unhealthy and unattractive place to be.

The resident duck and goose population has dropped from about 500 birds in 2018 to about 200 today, Ertzner said. She credits a city ordinance and public education campaign against feeding waterfowl with curbing a problem that plagues parks and golf courses from Maine to Australia.

Conservation efforts have allowed some waterfowl populations to flourish, including Canada geese, whose numbers have burgeoned in the United States, increasing 16 times since the 1970s, from 230,000 to 3.9 million, wildlife experts say.

Grassy expanses near water resources provide ideal habitat where ducks and geese run afoul of human activity. In South Portland, city workers use machines to remove droppings from Mill Creek Park before special events, which is about twice a month spring through fall.

Portland officials are taking steps to address a growing geese population in Deering Oaks park, said Jessica Grondin, city spokesperson. And in Rangeley, selectmen recently consulted with a USDA wildlife biologist before they approved a plan to reduce the town’s Canada geese population of about 100 birds using a carbon dioxide-filled chamber.

Culling the flock in South Portland is still off the table, Ertzner said, both because of the public opposition it most likely would generate and because it wouldn’t eradicate the problem.

“There is no silver bullet to solve this,” Ertzner said. “We’re always going to have resident ducks and geese, even if we do everything that’s recommended.”

Among the likely options in South Portland is the purchase of a remote-control airboat that travels on land and water to disrupt and harass ducks and geese into leaving the park, Ertzner said. Priced at $25 to $250, it also might be one of the least expensive options, if not the easiest to deploy.

MULTIFACETED APPROACH RECOMMENDED

“Harassment techniques should be employed immediately when the waterfowl show up in the spring,” Joseph Badger, the USDA wildlife expert, advised in an email to Ertzner. “A variety of methods should be aggressively deployed at all times of day and night for best results.”

Resident ducks and geese can quickly become desensitized to some harassment or deterrent techniques, so using a variety of methods in coordination is crucial, Badger said.

He recommended spraying park grass with Flight Control Max, a nontoxic “anti-feedant” that causes digestive irritation in geese so they move on in search of new food sources. It sells for $315 per gallon online.

Made with anthraquinone, a biochemical pesticide, it targets geese and poses “negligible” risk to humans and “minimal to nonexistent risk” to other wildlife, according to the U.S. Environmental Protection Agency. It also makes grass look different to geese, so it also provides a visual deterrent.

“This product is applied to the lawn and usually needs to be reapplied every 3-4 weeks, commonly after mowing, since cutting the grass removes the product,” Badger said.

He also suggested landscape modifications to deter geese and ducks from hanging around, such as installing a 3- to 5-foot-tall fence around Mill Creek Pond.

“This has been completed in numerous settings and has proven effective at reducing the water’s attractiveness,” Badger said.

Other suggestions included planting thick hedgerows around the pond or lining the banks with large boulders to make it difficult for ducks and geese to access the water from land.

None of the pond-blocking options seem viable given the potential cost and impact on the public’s ability to see and access the pond, which is used for ice skating in winter.

“It will be costly and people are gonna hate it,” Ertzner said.

SPRING IMPLEMENTATION LIKELY

Ertzner and other South Portland officials have until next spring to develop and start implementing an expanded plan to control waterfowl in the park. It may require permits to interact with waterfowl that are normally protected under wildlife regulations, she said.

At Badger’s recommendation, it will include a stepped-up public education campaign against feeding ducks and geese, which naturally eat aquatic plants, grains, grasses, bugs and mollusks. Geese also eat berries, seeds and small fish.

“Make sure the no-feeding policy is enforced,” Badger advised. “Change signs, move signs, put them in front of benches. (Remove or relocate) benches which have become duck-feeding locations.”

Ducks and geese don’t need additional food from humans, experts say. Moreover, it usually provides poor nutrition, can cause disease and death, delays migration, is unsanitary, causes water pollution, and promotes unnatural behavior and aggression toward humans.

“People could really help by not feeding them,” Ertzner said.