A community group is calling on the Toronto and Region Conservation Authority (TRCA) to reassess its wildlife management procedures after a noticeable cormorant population increase reignites concerns over foul odours, dying trees, and impacts on daily life.
Tony Farebrother, Chair of the Toronto Islands Community Association (TICA), says the marina and its operators, along with residents of the Island, are expressing anger and concern over the nesting habits of cormorant birds in the region, including negative impacts on the island’s businesses.
“Whatever is being done isn’t sufficient, because the birds are winning. Something else has to be added to the mix. I don’t know the answer. Whatever is being done so far, the cormorants are actually increasing in number. That’s not a good sign that you’re successful,” Farebrother told Now Toronto on Wednesday.
WHAT ARE CORMORANTS?
Double-crested cormorants are a native species of medium-to-large waterbirds with long necks, and bright yellow beaks, often found along the waterfront. They primarily feed on fish, and nest in large colonies near islands, cliffs, and trees near water.
“Cormorants require tall trees for nesting without human disturbance and access to fish for food. There is excellent habitat available for cormorants in Toronto, particularly at Tommy Thompson Park and Toronto Island Park,” Karen McDonald, Senior Manager, Ecosystem Management with TRCA, said in a statement to Now Toronto on Tuesday.
In the 1970s, the black birds were on the verge of extinction due to contaminants, overfishing, and poaching. Since then, environmental conditions have improved, allowing for the cormorant population to recover.
Today, cormorants are protected under the Fish and Wildlife Conservation Act, managed by the TRCA under the Ontario’s Ministry of Natural Resources (MNR).
WHY ARE CORMORANTS BEING REMOVED FROM THE ISLAND?
McDonald says cormorants naturally kill the trees they nest in as their feces, named guano, coats the leaves, affecting the photosynthesis process.
“Their guano is also acidic, which results in impacts to the soil around the tree and contributes to the tree’s deteriorating health. And lastly, cormorants frequently break branches to add to their nests, and the nest itself can become so heavy that it damages the tree.”
But the trees are not the only living species being impacted by the birds.
Farebrother says the strong smell of guano along with their loud noise are difficult to manage during the summertime, leaving residents unable to open their windows and enjoy regular activities.
“There’s always been people concerned about the noise because there’s huge flocks of them, so they can be somewhat noisy. When it’s hot and humid, and the wind is blowing this way, the smell just settles, and it’s like a huge amount of dead-fish smell. It’s not very pleasant in the summertime,” Farebrother said.
Farebrother says businesses along the waterfront are also being impacted, including fishers, dockers and boating facilities.
“Other people on the island certainly are getting it. The smell and the destruction is affecting their business…And so they, you know, don’t want to stay because of the smell and the noise, and possibly even sometimes the birds will nest right on the main island, not just across where they are, and so you might actually have guano drop onto you or onto your boat.”
CORMORANT POPULATION INCREASING
The TRCA estimates that approximately 4,500 birds are currently nesting at the well-known Island, compared with 1,200 in 2024, marking a sharp increase. Additionally, the organization estimates that 8,000 cormorants are nesting at Tommy Thompson Park.
“This year has seen a remarkable increase in cormorant nesting at Toronto Island Park,” McDonald said. “The increase in the Toronto Island population is likely due to immigration coming from Tommy Thompson Park.”
Cormorants began nesting at Toronto Island Park in spring 2022, causing concerns over the impact on trees and recreational activities in the area. At the time, the City of Toronto prompted its Parks and Recreation team to work with the TRCA to discourage the waterbirds from nesting on the island.
But in 2024, two bald eagles made Centre Island their home for the first time in 75 years, prompting the city to install a 100-metre buffer zone around their nest to minimize human disturbance. But the measure inadvertently created an environment where cormorant populations flourished, with numbers nearly doubling.
“Well, the cormorants took advantage of that and moved closer. Most of the nests were inside that protected area, and it was more intense in that area, and that’s continued now. The Eagles Nest earlier than the cormorants, but once the Eagles are nesting, they don’t disturb that area,” Farebrother said.
EFFORTS TO SAFELY REMOVE CORMORANTS FROM THE ISLAND
The TRCA has been working to safely deter and remove the cormorants from the island and back to Tommy Thompson Park, utilizing a three-phase method to guide the birds away from the island.
Phase one happens in the winter, when all cormorant nests from the previous year are removed. During the spring’s phase two, the TRCA uses various deterrent methods, such as using pyrotechnics, to scare the birds away from particular areas. Phase three then occurs during the summer, with the birds being monitored for roosting and deterred if necessary.
The TRCA has also designed a platform structure in 2024 to move cormorants’ nests on the ground instead of on the trees, which McDonald says has been successfully used by the birds.
Despite the TRCA’s efforts, Farebrother still worries the birds may migrate and spread.
“We have occasionally seen some attempt to roost on Algonquin Island, where some of us live, and that was worrisome, because if they’re going to, you know, continue to spread out, they’re going to be closer and closer, and then, you know, they the destruction and the smell and all the rest will be bothersome,” Farebrother said.
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