By David Heitz / NewsBreak Denver
(Denver, Colo.) Denver's parks department is confident its efforts to control the Canada geese population will prevent the need to euthanize birds this year.
Denver's year-round goose population has leveled off, so the city doesn't need to use its Goosinator to chase the birds during breeding season.
The Goosinator, a remote-controlled device that looks like a children's toy, is painted to look like a predator and makes noise to chase geese away.
Denver Parks and Recreation Executive Director Scott Gilmore said using the Goosinator and oiling goose eggs, among taking other measures, has reduced its year-round goose population. Gilmore said that the geese flocks at area parks no longer exceed manageable numbers.
The goose program works to compare and contrast data to assess the efficacy of different strategies to determine the best options to manage the goose population in the future.
Denver built goose paradise
Gilmore also is a wildlife ecologist and worked 17 years for the state in that job. He said geese are not native to Denver but came here because the parks department built a paradise for them.
Lush green spaces with man-made lakes turned Denver parks into goose gathering places. The geese flock to Washington, City, Garfield, and Sloan's Lake parks. According to city counts, in some parks, the geese outnumbered people three to one.
Gilmore said in the 1950s, Denver did not have geese. "People wanted them and moved them here."
But geese can become aggressive when fed, the parks department warns online. They also don't need handouts, so people should not give them food. Geese can be particularly territorial during mating season and when hatchlings emerge.
In 2015, less than 11,000 geese occupied Denver's parks as permanent residents. By 2019, the population bloated to more than 95,000 geese, including 44,000 breeding pairs. Washington Park used to be home to more than 700 birds; today, there only are about 50 geese at the park, Gilmore said.
Denver captured, killed geese
Denver allows hunting of geese with a permit but not with guns. Some cities use dogs, fireworks, or gunfire to chase the birds away. Denver uses its goosinator, which likely helped spare hundreds of goose lives. Its success and other measures have made killing the geese unnecessary.
Denver captured and shipped 1,662 geese to be slaughtered at a processing facility in 2019. Details are scarce. The parks department won't specify how the birds were killed to protect workers from the United States Department of Agriculture, which performed the exterminations under contract with the city.
"For the privacy and protection of the processor and recipients of donated meat, identifiable information will remain private," the parks department reported online in April 2020. "DPR will rely on the expertise of the contractor to determine the process for how resident geese will be rounded up and euthanized."
The department reports the geese were "humanely" euthanized following American Veterinary Medical Association guidelines at a Colorado Department of Public Health and Environment-approved facility. "Not all resident geese at these locations were removed to ensure continued public enjoyment of wildlife within Denver parks," the parks department reported.
Other ways Denver hazes geese
Sometimes parks employees chase geese with golf carts. "Chasing geese by foot or in a golf cart is labor-intensive, but in conjunction with other harassment methods, it can be successful if persistent," according to a parks department report. "The idea is to chase geese long enough to cause them to go elsewhere. Some DPR staff use this method in smaller parks."
The city even used lasers. "Lasers have been used to harass migratory geese," the 2020 report explains. "The lasers are used at dawn, dusk and at night during times when flocks prepare to bed for the evening. Geese think that the lasers are predators and will not land for the evening."
Using lasers provides an alternative to pyrotechnics and propane cannons to avoid the noise caused by the other techniques. Denver tried using lasers with little success, but it continues to explore using them in some areas.
Some people ask why the city doesn't relocate the geese. The parks department has an answer for that in their report, too. "Relocation of Canada geese in Denver parks was discontinued in 1999 by Colorado Parks and Wildlife for various reasons. This method of goose management proved to be unsuccessful — no other states wanted Colorado's nuisance geese and relocation was costly, labor intensive and required a special federal permit."
Oiling eggs highly effective
The parks department began its egg oiling program soon after the relocations stopped. "During the breeding season, March through June, staff and volunteers locate nests throughout Denver parks and spray 100 percent grade corn oil on goose eggs," according to the city's Resident Canada Goose Management Program. "The corn oil blocks the air passages of the eggshell and prevents the embryo from developing. This method is quite successful due to the minimal disturbance to the nest, allowing the female goose to continue incubation of the treated eggs and minimizes her chance of re-nesting."
The city accepts volunteers who want to help with egg oiling. Gilmore said this is a way for people to keep geese from being exterminated.
"Although labor intensive, oiling Canada goose eggs has proven to be a successful method of population management," according to the program. "The number of goose nests and eggs that have been located and oiled throughout Denver parks has consistently increased each year, resulting in fewer goslings."