Canada geese causing problems for cities as experts struggle to reduce populations

While Canada geese are a national symbol, the animals can cause a lot of problems for the cities they reside in, leaving officials grappling to find solutions to mitigate their populations.

In recent decades, B.C.-based urban biodiversity planner Jennifer Rae Pierce says Canada geese have been derided as urban pests, overrunning new habitats across North America, especially in cities.

Pierce told CTV's Your Morning on Wednesday that the issue is not the migrating geese, but rather the "resident geese" that have, in some cases, taken up residence in urban areas year-round.

She explained the two are the same species of bird, but each has different migrating behaviours.

"The geese that do not migrate and stay in one place have larger impacts on the ecosystem because they're not behaving the way that they were evolved to behave. This means that their grazing patterns have a higher impact and also the feces or when they're pooping on the ground, they're not moving around as much," Pierce said.

A single goose can defecate up to once every 12 minutes, producing up to two pounds of feces each day, according to Go Geese Go. Pierce said large flocks of this can strip grassy areas and damage irrigation systems.

Canada geese can also cause agricultural and natural resource damage, including attacking grain crops, overgrazing pastures and degrading water quality on farms.

Geese can also be aggressive and can sometimes cause injuries, especially to small children or pets when nesting in cities.

Pierce said these issues are more common during the spring because this is when goslings have hatched and the adult birds at the same time are molting -- replacing all body, wing, and tail feathers shortly after the nesting season.

"This means that the geese are less able to fly and they're congregating in larger numbers together as certain geese pairings will look out for a large group of goslings at one time," Pierce said, adding that the impact of geese is then concentrated in urban areas without predators.

According to Environment and Climate Change Canada, at least seven million Canada geese inhabit North America, with about 4.5 million in Canada.

However, Canada geese and their growing population are a Canadian-made problem.

Prior to European colonization, the historical nesting grounds of Canada geese were limited to southwest Ontario and the southern Prairies. But by the turn of the 20th century, unregulated hunting drove Canada geese to the brink of extinction from these native habitats.

This prompted a concerted effort by wildlife officials who bred the birds on their homesteads to boost the numbers of Canada geese and introduce them to new areas.

As forests were razed in favour of commercial crops and manicured lawns and waterfronts, the introduced geese, who were never taught to migrate during the reintroduction period, flocked to these open pastures that offer an abundant supply of food and relatively few predators.

"Without having predators in place and other natural methods of population control, those populations are just growing exponentially. The [geese] find that cities are incredible places of habitat for them with abundant food, very few predators, and so it's just the perfect place for a population increase," Pierce said.

Because of this, the federal government approves hundreds of permits for culling and using predators to scare away the geese each year. However, culling can be controversial and some wildlife experts argue it is ineffective in the long term, as geese lay eggs rapidly and in large numbers.

Pierce said a variety of techniques can be used to reduce populations, such as egg switching and birth control.

"The most common is to handle the population at the point of egg, which usually involves egg addling or some other system of making the eggs non-viable," she explained.

Pierce said adjusting areas so they seem less attractive to geese in what is called habitat modification can also help.

"This can be quite simple, just involving things such as providing shrubbery or low vegetation around water edges, where predators could in theory be in hiding and this would make that area less safe for them," she said.

"Or even in a large grassy area ensuring that there are branches over the grass so that the geese aren't able to have nice, clear take off areas."

With a file from The Canadian Press