Science·What on Earth?

How geese came to dominate our urban landscapes

In this week's issue of our environment newsletter, we look at why Canada geese seem so abundant these days and we gather some of your photos for the Nature Conservancy of Canada's recent Big Backyard BioBlitz.

Also: A collection of your photos from the Big Backyard BioBlitz

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(Sködt McNalty/CBC)

Hello, Earthlings! This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

  • How geese came to dominate our urban landscapes
  • A collection of your photos from the Big Backyard BioBlitz
  • Quebec researcher studying concrete measures to cool highway heat islands

How geese came to dominate our urban landscapes

(Steve Dykes/Getty Images)

If you're seeing a lot of geese in your neighbourhood this summer, you're not alone. These large, black-necked birds have become ubiquitous in Canadian cities. And although these "honkers" are viewed by many as urban pests, the fact is that not too long ago, they were nearly extinct in North America.

"Canada geese are one of the greatest conservation success stories ever — to the point where you were lucky to find a goose back in the '50s, and now we're probably well over seven million geese estimated in North America," said Ralph Toninger, associate director of the restoration and resource management group with the Toronto and Region Conservation Authority.

At the turn of the 20th century, unregulated hunting drove Canada geese to the brink of extinction from their native habitats in North America. This prompted wildlife officials to put in place a conservation plan and reintroduce the birds to their traditional environments. 

Now, the birds known for flying in a V-formation have overrun new habitats across the continent. According to the Canadian Wildlife Service, Canada geese are considered to be overabundant in almost every province.

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The Canada geese population truly exploded in the 1970s with changes to our urban landscape. Manicured lawns, stormwater retention ponds and golf courses are ideal feeding and breeding grounds for them. In cities, Canada geese have no natural predators and can't be hunted. 

Historically, Canada geese are migratory birds that fly south for the winter. In some parts of Canada, however, they have become so comfortable that they've stopped migrating to breed and instead stay in the same place throughout the year. They have been dubbed "resident geese." 

While we've done a great job of protecting Canda geese, their sheer numbers are causing some headaches. From eating crops to causing traffic jams, geese have become an urban planning nightmare.

"Geese eat a lot and the consequence of eating a lot is that they poop a lot, so it's unsanitary," said Christian Roy, head of the migratory birds and wildlife health management unit with the Canadian Wildlife Service. "If they're close to the beach where people are hoping to swim, it could carry some health concerns."

Big gaggles of geese by stormwater ponds and along waterfronts can lead to unsafe levels of bacteria, nutrient overloads and algae blooms in the water, said Roy. Geese can also become aggressive when they believe their nests are under threat and can cause serious injury.

They're also causing problems at airports — geese pose a significant risk to aircraft because of their large size and flocking behaviour. All this has led municipalities to consider creative ways to control resident geese populations.

The City of Vancouver, for example, has put in place an egg-addling program.

"We take previously gathered and frozen eggs, we warm them up to body temperature and then replace the eggs in active nests with the frozen ones," said Dana McDonald, a planner with the City of Vancouver's Park Board planning and development team. "The geese return to their nests and the eggs just don't hatch and the geese kind of accept that and carry on."

McDonald said the city also uses dogs to scare geese away in some areas.

The City of Toronto is trying to make green spaces less attractive to the birds by putting up low fences to block access to water and reducing the amount of mowed lawn. 

"These are herbivores that are eating grass, and if you reduce the amount of green grass right beside a water body, that just makes the area less attractive [to them]," said Toninger.

Canada geese populations will likely keep increasing for years to come, but in some areas such as southern Ontario, numbers are starting to level off. Roy said that ultimately we've created the perfect environment for the birds, so we can't blame them for multiplying.

"[Canada geese] are really, really good parents and they mate for life and they're very, very protective," said Roy.

"I think we need to maybe consider them from a different angle — not necessarily a nuisance, but as an interesting species that's so adaptable."

Maya Lach Aidelbaum

Reader feedback

Further down in the newsletter, you'll find a gallery of photos readers sent to us to celebrate the Nature Conservancy of Canada's Big Backyard BioBlitz last weekend. But we also wanted to showcase an image Emily White sent us. She has been painting delightful images of the birds that she's been seeing, including the king rail, and posting them to her Instagram account.

(Submitted by Emily White)

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Old issues of What on Earth? are right here.

There's also a radio show and podcast! Extreme weather, from the current drought to floods, puts farmers on the front lines of climate change. Now, some are turning to regenerative farming to fight back. We get all the details and ask if it's enough to help stop climate change. What on Earth airs Sunday at 12:30 p.m., 1 p.m. in Newfoundland. Subscribe on your favourite podcast app or hear it on demand at CBC Listen.

The Big Picture: A backyard photo blitz

Last week, Canadians were invited to help science and conservation by uploading photos of plants, animals and fungi to the iNaturalist app as part of the Nature Conservancy of Canada's Big Backyard BioBlitz. If you took photos last weekend and haven't uploaded them yet, it's not too late to add them, the NCC says. Just make sure you have the correct date if you want them to be part of the BioBlitz.

In the meantime, here's a slideshow of some of the photos you sent to us. (You'll find the species or group identified by iNaturalist, as well as the photographer's name and location, below.)

(Submitted by multiple readers)

Credits: Half-black bumblebee, Cheryl MacLeod, Notre-Dame-du-Laus, Que.; Lance-tipped darner, Sharlyn Bullen, Sunshine Coast, B.C.; Eastern giant swallowtail, Lana Bastien, Windsor, Ont.; Northern crescent, Nancy Wilson, Bayfield, Ont.; Northern walkingstick, Chris Baas, Pinery Provincial Park, Ont.; Monarch butterfly, Dinesh Sharma, London, Ont.; Garden whites, Jenn Maddigan, Whitby, Ont.; Two-striped grasshopper, Wendy Ash, Kanata, Ont.; Black swallowtail, K. Peel, St. Mary's, Ont.; Northern flicker, Rose Rathwell, Exeter, Ont.; Bumblebee, Anant Nagpur, Ottawa.

Hot and bothered: Provocative ideas from around the web

  • People of colour face many barriers to experiencing nature. Engaging in activities like camping and fishing has traditionally been more difficult for non-white communities because of factors such as the high cost of equipment and overwhelmingly white media portrayals of people outdoors. A new project in Ontario wants to change that by educating non-white communities about nature and showcasing photos of BIPOC Canadians out enjoying it.

  • As the western U.S. continues to deal with drought and water shortages, cities like Los Angeles, Phoenix and San Diego are looking for ways to reuse as much wastewater as possible. One project is working to bring purified wastewater directly to people's taps — as opposed to the current practice of filtering wastewater through a groundwater basin before it reaches the faucet.

  • A landscape architect is proposing using large quantities of oysters to defend New York City's coast from rising sea levels and water pollution. When there's enough of them, oysters can create reefs that break storm surges, protect the city from further flooding damage and filter out toxic pollutants.

Quebec researcher studying concrete measures to cool highway heat islands

(Jessica Wu/CBC)

They don't look high-tech, but temperature sensors attached to wooden stakes along the autoroutes that criss-cross Laval, Que., may provide the data that could help the city — and eventually other municipalities — become cooler, shadier places to live.

These installations can be seen at 10 sites along highways 13, 15, 19 and 440.

They are all part of a heat island research project being conducted by a young scientist whose goal is to soften the impact of large swaths of pavement and concrete near urban centres.

Hugo Ouellet convinced the City of Laval and the Quebec Transport Ministry to let him install thermometer systems that continuously record the temperatures at those sites. The project is part of his master's degree thesis in biological sciences at the University of Quebec in Montreal (UQAM).

Ouellet says highways contribute significantly to higher temperatures in neighbourhoods that are nearby — and to heat-related discomfort and illnesses. He is studying how biodiversity can reduce heat islands in highway environments. 

He wants to know what kind of green space is the most effective, what kind of vegetation should be planted and how the plants should be arranged.

"I think it's a great start in making greener cities," said Ouellet.

Alain Paquette, the professor at UQAM supervising Ouellet's project, said the negative impact of rising temperatures on people's health is already well-documented.

"It doesn't have to be 10 degrees. It can be just one degree higher than normal, and it will already have an effect on people's health."

Paquette said that everyone benefits from a reduction of temperatures, but it especially helps people who already suffer from conditions made worse by heat, including asthma and other cardiorespiratory diseases.

Paquette said lowering temperatures will also help animals and plants that live in these environments.

Until now, most heat island research has concentrated on downtown areas — looking at how to offset the heat created by parking lots, schoolyards and dense construction with trees and green spaces.

That means there is little data on heat islands near major roadways, which is why Ouellet describes his project as "one of the first" to address the issue. There is growing interest from municipalities and Quebec's transportation ministry to do something about this.

"What we need is data and information to guide, and to make it count," said Paquette.

Ouellet said there are plenty of potential solutions to highway heat. Something as simple as greening the spaces near off-ramps with trees could be "an easy fix that will help the city a lot with heat islands."

"I hope I'm going to see something [come] out of it." 

Jessica Wu

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Editor: Andre Mayer | Logo design: Sködt McNalty

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