Making cities wildlife-friendly seems like a big task, best left to conservation groups and governments with money and manpower for large projects like building parks and protecting species. But new research shows that there’s a lot of power in small spaces and small projects too, and anyone with a little patch of grass or a patio outside their home can also do their part for their city’s wildlife.
While they’re often underestimated and even ignored in urban conservation efforts, urban yards are really important to birds, says biologist J. Amy Belaire. In some cities, residential yards can make up more than a third of the land area, and create a patchwork of green spaces amid the concrete and asphalt that connect more “natural” habitats like forests and parks and create additional space for birds to live. If they’re managed correctly, Belaire says, the collective effect of all those yards can have a huge impact.
Belaire and other researchers from the University of Illinois spent some summer weeks canvassing several neighborhoods in Chicago to assess their bird populations and figure out what drew birds to them. At 25 different sites, they counted birds during the summer breeding season and talked to hundreds of homeowners about how their yards might attract or deter birds. They also used mapping software to look at the characteristics that might be important to birds — like the amount of vegetation, tree cover and open space or the distance to the nearest river — in the neighborhoods and larger landscapes around their survey sites.
They found that Chicagoans count a surprising number of bird species among their neighbors, and identified 36 different species across their study sites. The sites had an average of 16 different species, and some were home to as many as 21. More importantly, they learned that maintaining that abundance and diversity had more to do with the aggregate effects of nearby yards than the characteristics of a neighborhood or city section. In mathematical models that accounted for all the bird-friendly factors at the yard, neighborhood and landscape scales, alone or in combination with each other, the yards alone best explained the number of birds found. In other words, the “bottom-up” influence of a group of bird-friendly yards was more important in attracting birds than bigger “top-down” environmental projects like planting street trees or maintaining parks or undeveloped land in a neighborhood.
Belaire says the results suggest that it’s time to start “thinking outside the park” and recognize the impact that urban residents and their yards can have on a city’s wildlife. How can people steer that impact? The homeowner surveys revealed a few things that, when implemented across a city block or neighborhood, can be a boon to birds. First, a healthy mix of evergreen and deciduous trees in yards gives birds more diverse vertical space to live and feed in. Second, plants that produce fruits and berries give them something to eat. Birdfeeders, which do the same job, didn’t have the same effect. The researchers found that almost half of the species they ID’d rarely used birdfeeders, but nearly all of them eat fruit or berries. (In other cities with different native birds, birdfeeders may do more good.) Lastly, keeping cats indoors prevents birds from being scared off or killed.
Getting a group of neighbors to all maintain their yards a certain way could be a tall order, but the researchers say there are two different ways to go about it. Grassroots campaigns by conservation groups, neighborhood associations or even a small, informal group of bird-loving neighbors could convince people to make changes to their yards and support birds by highlighting how many people doing small things, like planting a berry bush, can have a big impact. On the other hand, municipal governments and homeowners associations could use their authority or certain incentives to motivate people. Chicago’s “Sustainable Backyard Program,” for example, offers residents rebates for native plants purchased for their yards.
Getting neighbors to work together toward these goals isn’t just good for the birds. It’s good for people, too. Belaire says that yards and neighborhoods play another role in the “conservation puzzle” by connecting people with wildlife and points to other research that shows that people who manage their yards to attract wildlife report better quality of life and emotional well-being. Plus, birds provide valuable “ecosystem services” like dispersing seeds and controlling insect populations, and their presence can even boost the sale price of a house.
Matt Soniak writes about science, history and Bruce Springsteen for a variety of outlets. His work has appeared in print and online for Mental Floss, The Week, Slate, Men’s Health, Scientific American, The Atlantic, ScienceNow and others. He lives in Philadelphia.