Clock ticking on options to control geese population

Egg oiling, culling being considered as nesting season nears

Jane Reuter
Special to Colorado Community Media
Posted 3/4/20

The best way to manage Denver’s goose population is not by culling, but oiling eggs — in far greater numbers than Denver Parks and Recreation has done in the past, say local goose advocates. But …

This item is available in full to subscribers.

Please log in to continue

Log in

Don't have an ID?

Print subscribers

If you're a print subscriber, but do not yet have an online account, click here to create one.


Click here to see your options for becoming a subscriber.

If you made a voluntary contribution in 2019-2020, but do not yet have an online account, click here to create one at no additional charge. VIP Digital Access includes access to all websites and online content.

Our print publications are advertiser supported. For those wishing to access our content online, we have implemented a small charge so we may continue to provide our valued readers and community with unique, high quality local content. Thank you for supporting your local newspaper.

Clock ticking on options to control geese population

Egg oiling, culling being considered as nesting season nears


The best way to manage Denver’s goose population is not by culling, but oiling eggs — in far greater numbers than Denver Parks and Recreation has done in the past, say local goose advocates.

But the clock is ticking.

“The optimal time to oil is between April 1 and April 10,” said Courtney DeWinter, spokesperson for Canada Geese Protection Colorado (CGPC), “which means we have only a few weeks.”

In that time, she hopes to gain the city’s support and mobilize the manpower needed to oil eggs en masse — a labor-intensive process that would extend far beyond public parks to private properties where geese also nest.

To have the needed effect, CGPC believes 10,000 to 12,000 eggs would need to be oiled, which is nearly triple the amount Denver Parks has oiled in the past as part of its own program.

“We are practical problem solvers,” DeWinter said. “This is a financially feasible solution we’re asking the city to deploy instead of killing. It’s an amazing opportunity to make a dent on the population in a humane fashion.”

Condoned by the Humane Society of the United States as “the humane way to limit flock growth and stabilize goose populations,” oiling works by blocking the passage of air through the shell, preventing the embryo from developing. However, timing of the oiling is critical. To do so humanely, the process must be completed before the eggs begin to develop. Eggs can be tested to determine the stage of development by putting them in water. Developing eggs will float and should not be oiled.

Last year’s decision to cull

In June and July 2019, Denver Parks partnered with the United States Department of Agriculture to round up about 1,700 geese from four city parks, including Washington and City parks. The geese were killed at a northern Colorado processing plant and their meat was distributed to families in need.

Denver Parks’ website says the decision to cull followed 15 years of goose management tactics — including oiling — that failed to keep the population in check, resulting in “an unnatural number of geese” in the parks, and an amount of goose excrement that degraded the environment and the park experience.

Denver Parks has a three-year contract with the USDA, but the city said it is still considering its plan for 2020.

Cynthia Karvaski, spokesperson for Denver Parks, said a decision on whether to cull this year will be made after counts of the geese that are still in the parks are conducted sometime in May. Any decision regarding culling will be made prior to molting season, which begins in June or July.

She added the 2019 action was a last resort.

“We were always hoping it wouldn’t come to that, but unfortunately the population is no longer manageable,” Karvaski said. “And while we’ve heard from people that are against it, we are receiving hundreds and hundreds of messages from people saying ‘thank you.’”

Still, the city will continue a multi-pronged approach to the issue, Karvaski said, and this year, will partner with CGPC for the effort.

In 2019, Kavarski said Denver Parks oiled about 3,100 eggs. She estimates at least that many will be oiled this year as well.

But DeWinter said Denver Parks hasn’t oiled enough eggs in the past to put a significant dent in the goose population. Denver Parks estimates its parks are home to about 5,000 resident geese — those born in Denver that live here year-round. A separate population of migratory geese flies to Denver from Canada each fall, but most migrate back to Canada in the spring.

DeWinter argues that because the female goose lays an average of five eggs, the city’s oiling effort is only about one-third of what needs to be done.

Heavy oiling in coastal areas

Similar egg oiling programs have been used in communities across the country.

Greenwich, Connecticut, started a goose management program 15 years ago based on egg oiling, hazing and public education. Director of Environmental Affairs Patricia Sesto said the community was motivated to take action because of concerns about bacteria from goose waste on beaches and in the water.

There, geese are hazed with dogs and eggs are oiled on city and private property.

While the dog hazing keeps geese away from specific waterways and properties, Sesto said, “hazing doesn’t manage the population. It just manages those particular geese on a particular property. The oiling changes the population.”

Greenwich’s program also includes educating residents on how to oil the eggs themselves, but residents can also allow the city to do so, Sesto said.

Controlling a goose overpopulation “is not just a municipal solution. It has to be a community solution,” Sesto said. “If you’re only doing it in public parks, you’ll never get a handle on it.”

Despite the success of Greenwich’s nonlethal program, Sesto doesn’t oppose culling if a big population reduction is needed.

“Euthanasia is going to knock the population down, then you can hold that steady with the egg oiling,” Sesto said.

The GeesePeace program

Greenwich’s program was based on a protocol created by a Virginia-based nonprofit called GeesePeace, which advocates a three-pronged approach of egg oiling, dog hazing and an educational campaign urging people not to feed geese.

GeesePeace national program director David Feld, a retired engineer from Virginia, co-founded the program in 1999 because of a conflict concerning geese in his community.

Feld attended a January meeting in Denver about the local Canada goose issue.

In addition to oiling, Feld said the key is to make Denver’s waterways — which serve as safe retreats for geese where most predators can’t go — undesirable for geese. That’s done with dogs on shore and in boats on the water, stationed during a specific time period.

Feld said the program is low cost and effective, in large part because it taps into a Canada goose’s inbred desire to fly north — an instinct Feld said is present even in non-migratory resident geese like those found in Denver.

If geese find the environment undesirable, they’ll go elsewhere, Feld said.

“It always works,” he said. “They either fly north or fly to other water bodies.”

Geese won’t leave an area, however, Feld added, if they have goslings, which is why he believes egg oiling is also critical.

“I’m not a goose lover. I’m an engineer and I like to solve problems,” he said. “This is high gain and low cost. It gets both sides working together instead of fighting. Right now in Denver, you have a broken community. There’s no reason why that should be.”

Culling a common practice

Washington Park resident Steve Spirn, who represents Citizens to Restore the Parks, said his group supports any method that will keep Denver parks free of goose waste.

He and his neighbors helped create the citizen group in 2016, garnering support from 1,500 people who signed a petition to resolve the issue.

“Our issue has been about not stepping in goose poop,” Spirn said. “There are legitimate health and safety issues. We’ve collected at least 50 scientific and medical papers to support that. And overpopulation can cause problems, including for the geese themselves.”

Spirn added that Citizens to Restore the Parks encouraged city council and the parks department to take nonlethal action, but was content with Denver Parks’ decision to cull.

“You move to Colorado and Denver for nature, and animals are part of nature,” Spirn said. “The difference is this — the nonlethal doesn’t work. Our position was and is the last step may have to be lethal.”

He said the group felt the overpopulation of geese in parks got to the point that culling was necessary, which in turn, likely reduced some of the health and safety issues.

“We don’t have enough expertise to know what else they could have done short of culling,” Spirn said. “We’d be most happy if nonlethal would work. If there are other methods to be tried, we’re in favor. But we’re also realistic.”

Denver Parks’ Karvaski said culling is a commonly used technique, often implemented with no public input or objection.

“We have, for years, taken community input regarding the situation,” Karvaski said. “But we’ve been tasked with the management of wildlife in the city. We make the best decision we can based on that responsibility.”


Our Papers

Ad blocker detected

We have noticed you are using an ad blocking plugin in your browser.

The revenue we receive from our advertisers helps make this site possible. We request you whitelist our site.