WSB: Harassing geese may not keep them away

In Chicago, geese just went to the park for a while

Of all the species that create conflicts with humans in Illinois, Canada geese are among the biggest offenders—particularly in urban areas. They leave piles of droppings, harass joggers and sometimes even collide with aircraft.

Wildlife managers often try harassing them to scare them away. But researchers recently found that may not be the best solution.

“Our work was started to understand geese behavior to mitigate their threat to airports in Chicago,” said Michael Ward, a professor in the Department of Natural Resources and Environmental Sciences at the University of Illinois and the senior author of a study published in the Wildlife Society Bulletin, led by his PhD student, Ryan Askren.

Managers had tried harassing geese that stuck around for the winter to try to drive them to agricultural areas or migrate south. Ward and his team wanted to see how successful these efforts were.

To find out, they harassed the birds by clacking boards together in front of them and used accelerometers—similar to FitBits that people wear the count their steps—placed around the Canada geese’s (Branta canadensis) necks to record their reactions. When the geese fed, the device reflected them tipping their head down. When they were alerted, the devices showed them popping their heads up to look for threats. Using machine learning, the team could characterize these behaviors and incorporate GPS data to see how far the geese would go to avoid harassment.

Looking both at migratory geese, which summer in northern Canada and, resident geese, which stay in Chicago year-round, the researchers found that neither group fled very far. Most—especially resident geese that knew the area well—just went to a nearby park and came back within the hour. And they weren’t draining their energy reserves. “The colder it got, the less feeding they would do, and the more sitting they would do,” Ward said.

The team suspects the geese have learned they’re safe from hunting in Chicago, but if they migrate south, they could end up being harvested.

For harassment to work, Ward said, managers may need to perform it at very cold times of the year when geese need to travel farther to find resources. But sending people outside when it’s negative 20 degrees Fahrenheit to scare away geese may not be very practical.

To successfully get rid of geese, Ward said, harassment may not be enough. “You have to really scare them or harvest them, or make the cost of sticking around there high,” he said.

Geese pose a growing problem, particularly around airports, where they can cause damage to aircraft. “That’s where you’re going to have to put the most effort and most intensive management,” he said.

This article features research that was published in a TWS peer-reviewed journal. Individual online access to all TWS journal articles is a benefit of membership.  Join TWS now to read the latest in wildlife research.

Header Image: Ryan Askren, pictured with a collared Canada goose, worked with University of Illinois researcher Mike Ward and others to determine how well harassment repels nuisance Canada geese. Credit: Courtesy Ryan Askren