Wildlife
Urban and migratory birds rely on city spaces to rest and recharge; here’s how you can help
For better or worse, my home office window faces directly into the fanning branches of a great big, mature elm, the same species peppered throughout my urban Winnipeg neighbourhood.
For better, because I can watch a seasonal procession of long-distance migratory birds every spring and fall just over the top of my computer screen. Each day brings a new complement of travellers, such as Canada or Tennessee Warblers singing and chasing down insects. For worse, because sometimes those very same birds appear during online meetings, and I have to sit on my hands and resist the urge to grab my binoculars.
However, when something like a scarlet tanager shows up, it’s hard not to lose your composure. Recently, one hovered in mid-air like a hummingbird just a metre or so from my window, catching a beam of sunlight illuminating its blood-red feathers like it was fanning a hot ember. But it’s not just its appearance that inspires.
Like many migratory songbirds, scarlet tanagers are an evolutionary marvel of endurance. This fist-sized bird, which weighs about the same as a light bulb, was probably nearing the end of a 10,000-kilometre nocturnal migratory journey that started only a few weeks before in the tropical Andes and would end in areas of Canada like southern Saskatchewan, Manitoba, southwestern Ontario, southern Quebec and parts of the Maritimes. The seeming ease with which migratory birds make these incredible intercontinental flights is to the envy of us land-lubbing primates. When this particular bird appeared in the middle of a meeting, I jumped from my office chair, blurting something incomprehensible, arms waving and pointing. My online colleagues rolled their eyes: Dr. Fraser getting excited by a bird is not an unusual occurrence.
I am grateful to the Winnipeg city planners of the last century who realized the importance of having well-treed urban neighbourhoods. Most of the streets near my house are lined with trees: ashes, bur oaks, and elms. In many places, the elm branches touch over the street, creating a shaded green tunnel in spring and summer that turns bright yellow in fall when the migrants are on their way back south. As a professional ornithologist, it is surprising even to me how many species I can spot from my home office window in the middle of urban Winnipeg. I don’t think that’s necessarily unique — other urban areas across Canada can be similar, given the right conditions.
Scientists and the public are increasingly interested in figuring out what we can do to help birds in an urban environment while also increasing backyard biodiversity. But ‘urban birds’ could be any species found in a city. Year-round residents, like black-capped chickadees and downy woodpeckers, need a decent amount of canopy cover and tree cavities for nesting. However, other ‘urban birds’ can be migratory species resting in one spot for just one night or a few hours, fuelling up like a commuter plane before heading to the next destination. These short stops to gas up are just as critical for birds as they are for planes.
Once you know what to look for, you’ll be surprised at the diversity of avian travellers passing through our city streets. For example, the blackpoll warbler, a 12-gram bird that could sit comfortably on a toonie, passes through southern Canadian cities in May on its way from South America to breeding sites in boreal forests as far north as Yukon. I also recently heard the whiny but endearing ‘song’ of the eastern wood peewee as it paused in a Winnipeg backyard near the end of its journey, also from the tropical Andes. Their distinct song, to me, is so whiny it sounds like a child pining for a third ice cream.
Many migratory species that pass through Canadian cities connect our neighbourhoods to distant landscapes. When purple martins (a swallow) and veeries (a thrush) appear in our backyards, they connect the local to distant tropical forests in the middle of the Amazon. Barn swallows, a once common bird that is now threatened, connect the eaves of our buildings, where it likes to nest, to the coasts of Argentina. American golden plovers (a big shorebird), with their long-distance flights, stitch the Canadian High Arctic to the eastern shores of South America and may take a much-needed pause in our urban areas. A few years ago, a keen-eyed student in my Biology of Birds class spotted one resting on some rocky landscaping on the University of Manitoba campus. Chimney swifts, those fast-flying chittering brown blurs we see over our buildings (true to their name, they like nesting in chimneys), eat bugs all summer in our cities, then head back to the Peruvian Andes to sit out our winter. I could go on, but that’s a sampling to provide some lift to your mental wings.
The details of these routes and connections have only recently been revealed through research using newly miniaturized tracking technology. My lab at the University of Manitoba has been a part of these efforts. While we used to say things like, “Oh, that species spends our winter somewhere down in Central America,” we can now say things like, “That bird in my yard picked a nice wooded patch near Belmopan, Belize, where it set up a winter territory, roosted in a patch of cacao at night, and stayed until April 26 at 6 p.m.” This is because the spatial precision and data storage capacity for these small devices has increased rapidly in recent years.
But there is much left to do. There are many species (more than 450 species can be found in Canada) and a lot of geography between here and Tierra del Fuego, an archipelago off the southernmost tip of South America. Even some of our most common species still hold mysteries. For example, we studied the movements of the American Robin using new live satellite tracking technology that is now just small enough to track some of our larger ‘small’ birds. We found that during fall migration, robins fly all over the city in search of fruit trees and any remaining insects, dispersing seeds between parks and riparian areas along the way. They did this for longer than we expected, staying for up to 30 days to refuel before continuing south to wintering sites that we found were as far away as Arkansas, U.S. Usually considered a daytime flier, we found robins really made tracks during the night, sometimes flying more than 400 kilometres at a stretch, when the cool, still air may allow them to save energy and go further.
Migrants like robins and warblers do a lot for us and the local ecology as they pass through our cities. Two examples are dispersing plant seeds and keeping our trees from getting too defoliated by leaf-chomping insects. And what do the birds need from us?
As travellers, birds need safe rest and refuelling sites, like a good airport or hotel. Generally, the more canopy cover and native plants in a city, the better. They also need safety from cats, bird-friendly windows that they won’t fly into, and lower levels of artificial light pollution so they don’t get disoriented during their night flights (the vast majority of otherwise daytime birds migrate at night).
According to an article in the scientific journal Avian Conservation and Ecology, house cats hunting outdoors kill an estimated 100 to 350 million birds per year in Canada. Keeping your cat on a leash while outdoors can help reduce this number. Alternatively, outfitting your cat with a brightly coloured, frilly collar with a bell can help while also making it the envy of the town! The birds will see and hear it coming and make their escape.
To reduce window collisions (bird injury or death caused by hitting a window), you can add sleek, single white dots to your window that break up the reflection and tell people you’re on the bird’s team. As I tell my students, since most window kills in Canada (some 25 million per year at last estimate) are at our homes, that gives every homeowner the power to make a difference.
Planting native plants is another way to help. Recent research shows this increases backyard diversity which will scale up the food chain to increase bird diversity. Most of the trees in a neighbourhood are in people’s yards, so private landowners are currently responsible for much of a city’s trees and, therefore, biodiversity.
Could our cities be bird-friendlier? Absolutely, particularly in a way that could benefit everyone, everywhere. Green spaces and their associated biodiversity tend to be patchy and not fairly accessible to everyone. More birds would mean cooler (both meanings of the word), more biodiverse, and human-friendlier cities, too. We should all get the benefits of bird distraction at our windows and the ecosystem services they provide in our cities and beyond.
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