There’s a battle with beavers going on in Mississauga’s north end — and the beavers are winning.
Last fall and over the winter, the City of Mississauga removed a number of beaver dams and beavers from in and around Sixteen Mile Creek and Osprey Marsh in the heart of the Lisgar community in the northwest part of the city near the Milton border.
The critters, who were safely relocated, had built dams that were causing drainage problems near the creek and marsh. That subsequently led to water flow problems, the city said.
Beavers safely evicted, problem solved.
Not so fast. Residents reported to Ward 10 Coun. Sue McFadden, who represents the area, that they’d spotted the beavers back in town this past spring.
The reported sightings prompted McFadden to declare she and City of Mississauga staff were going to keep a close eye on the situation as they searched for a better solution.
“Additional attention is being paid to this matter in the coming weeks,” the councillor told constituents at the time.
Aerial image shows location of Osprey Marsh and surrounding neighbourhoods.
Fast-forward to earlier this week when McFadden told residents in her latest update that beavers, among the largest living rodents in the world, “continue to reside along the Sixteen Mile Creek running through Lisgar.
“Despite previous efforts last winter to remove several beavers, another lodge and series of dams have been spotted further north within the tributary,” McFadden continued. “I have met with (City of Mississauga) staff on several occasions to develop short- and long-term plans to ensure that the beaver activity is not negatively impacting the stormwater system in this area.”
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McFadden said she’ll also host a townhall meeting, tentatively scheduled for Dec. 2, as her office continues to receive “ongoing messages of concern from the community.”
She noted the public meeting will specifically address “the topic of managing beavers within an urban setting,” adding city staff will present the municipality’s policies and operations, as well as Ontario government regulations they must adhere to.
“We’ll share what the current situation is in Lisgar and how our office and staff have been working to address it,” said McFadden, adding officials will also take questions and comments from residents at the meeting.
Photo taken last fall shows stagnant water along Sixteen Mile Creek that was supposed to have drained into Osprey Marsh but was impeded by beaver dams. (Photo: Ward 10 Mississauga Coun. Sue McFadden newsletter)
Osprey Marsh, located to the immediate northeast of Britannia Road West and Ninth Line, is a man-made stormwater pond (or series of smaller ponds) that regulates the flow of rainwater and snow melt from storm sewers and the Sixteen Mile Creek upstream.
Essentially, it’s an important feature that’s designed to control flooding, which has impacted that part of Mississauga for years.
McFadden said late last fall that her office worked closely with city staff to address “the recent situation of stagnant water” along the creek that was supposed to drain into Osprey Marsh.
“So far, two beaver dams have been removed — one south of the Osprey Boulevard bridge and one just north of it,” the councillor said in late 2025. “Reports of additional dams further upstream have been investigated and two more have been confirmed and will be removed shortly to restore proper flow and level of water in the creek. Relocation of the beavers to a more rural setting is also being considered in order to help manage proper operation of the stormwater system in the Lisgar community.”
The issue with the beavers continues as Osprey Marsh is undergoing its first-ever dredging to allow it to better perform its important function, the city said earlier.
The marsh/stormwater pond was built in the mid-1990s and the ongoing work this year will remove sediment that has settled at the bottom of the pond the past few decades.
The work is expected to be completed by the end of this year.
Osprey Marsh, much like nearby Lake Wabukayne to the east, has also become home to numerous types of birds and other wildlife over the years.
And this isn’t the first time the thick-furred, web-footed beavers have left an unwelcome mark on the site.
After a family of the semi-aquatic animals used their powerful jaws and strong teeth to destroy a number of trees along the trail that circles Osprey Marsh several years ago, the city looked to develop a beaver management strategy for all of Mississauga.
“Anyone who has walked the trail that circles Osprey Marsh will have noticed the damage to several trees by the family of beavers that call the marsh their home,” McFadden said at the time.
A member of the Lisgar Residents’ Association told INSAUGA Canada in 2022 that the beavers posed a considerable threat to trees in the area and they had actually destroyed closer to “hundreds of trees” instead of only several.
Furthermore, the community had been pushing the city for years to address the problem, which included “whole areas” that had been “clear-cut by beavers,” the resident added.
The residents’ group member also said at the time that beavers had on at least two occasions “attempted to dam up Osprey Marsh, but fortunately when we alerted city staff, they did dismantle the dam.”
Despite the ongoing problem, the city says North American beavers are native to Ontario “and part of a healthy ecosystem. They are beneficial to wetlands and watersheds as they create and preserve wetlands for many animal, bird and insect species.”
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