City painting oil on goose eggs to control population

7:34 AM, May 21, 2010   |    comments
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Denver Parks and Recreation uses oil to coat goose eggs. That keeps them from hatching. The process is called "addling," and is approved by the Division of Wildlife as a humane way to control goose populations.

Denver Parks and Recreation spokesperson Jill McGranahan says the city has been using this method for years. She says not every nest found in the city is oiled, but she estimates hundreds of nests have already been treated this year. A final count will not be available for several months.

McGranahan says the reason why there is an overpopulation of geese in Denver parks is because people feed them.

"There's so many outside influences in an urban setting, such as parks, with people feeding the animals and with feeding the geese, that they will lay more eggs than the park can naturally sustain," McGranahan said.

McGranahan says having too many geese in the parks threatens the environment as well as public health.

"What you run into when you have too many geese is both animal and human safety and health issues, and those have been well documented in our parks. We have had cases of botulism in the lakes and some of our parks because of the overpopulation of geese, and you run into health issues with the human population as well. So this is a way for us to mitigate that somewhat and to do it in a humane way that is controlled by the Division of Wildlife," she said.

McGranahan says the staff who do the addling undergo special training.

9NEWS checked with some other metro area cities to see if they utilize addling. Aurora Parks and Recreation does not, but leaves the option open. Mary Ann Bonnell, the lead naturalist for the Parks and Recreation Open Space Department for the City of Aurora, says the city does not have the same overpopulation problem as Denver. She says the department has found other ways to manage the goose population, including putting up signs telling people not to feed the birds, and avoiding the use of Kentucky Blue Grass in parks, which geese like to eat. Bonnell agrees the reason for any overpopulation of geese in parks is people feeding them.

The City of Boulder also does not utilize addling because it has a wildlife protection ordinance which prohibits it.

9NEWS learned about this story from a news tip. If you have a story you think we should know about, e-mail us at

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