7 Ways You Can Create an Oasis for Wildlife in Your Town

From planting trees to keeping cats indoors, here’s how to make animals feel at home in the big city.

(Photo: Getty Images)

Mar 13, 2015· 5 MIN READ
Richard Conniff is the author of House of Lost Worlds: Dinosaurs, Dynasties, and the Story of Life on Earth and other books.

A few years ago I was visiting the west Baltimore neighborhoods that inspired the American television series Homicide and The Wire. It was an urban wasteland, the brick row houses largely abandoned and boarded over. Whoever used to live here had long since gone away. Then we turned a corner onto North Carrollton Avenue, and for one city block it was a miracle: Handsome old trees formed a green canopy over the street. The houses were occupied and well tended. Someone was selling flavored ices at a stand in the shade in the middle of the block. The trees, a local woman told me, made all the difference, shading the houses, filtering the air, and making it easier to breathe. There were even birds and squirrels in the branches overhead.

That visit comes to mind because I have been thinking lately about ways to make cities more livable, for people and wildlife alike. The rapid urbanization of the Earth is the dominant movement of this century, and the sprawling, unplanned growth of cities and suburbs tends to leave behind patches of greenery only by accident—a few neglected parks, some street trees here and there, and the occasional sliver of protected land. Wildlife gets crowded out and pushed toward extinction.

Plenty of studies have already demonstrated that street trees and other green spaces tend to reduce crime, improve health, build stronger neighborhoods, encourage investment in housing stock, slow stormwater runoff and lower pollution. So let’s focus on the wildlife for now. Cities are not ideal wildlife habitat, but they are increasingly the only habitat. So what do we need to do to make room for wildlife in our increasingly urbanized world?

Plan for Green Space

Add some trees along a street, and you’ve got someplace where birds can rest or roost. Add a park at the end of that street, even a small one, and now you’ve got a spot where migrating birds can stop and eat on their way to or from their breeding grounds. Even adding just 150 square meters of green space—that’s 10 parking spaces—will bring one additional bird species into a neighborhood, according to a 2013 study by urban greening specialist Paige Warren at the University of Massachusetts–Amherst. The green space can include a community garden that benefits human residents. Bees, butterflies, and other pollinators will also show up, said Warren, “even in very dense metropolitan areas like in Manhattan.”

Make those Green Spaces Connect

Multiple parks or gardens that are connected make for exponentially better habitat. This is true at large scale: The Yellowstone to Yukon initiative, for example, seeks to connect protected lands so animals like grizzly bears and wolves can roam freely through this 2,000-mile-long ecosystem. But connectivity is important for green spaces at the neighborhood scale too, according to Madhusudan Katti, an ecologist at California State University, Fresno. For instance, “canopy corridors” created by street trees help squirrels to move safely from one park to another. Salamanders, on the other hand, may need road underpasses to get to the wetlands where they breed. For animals that can fly, like birds and bees, connectivity may be less about physical connection than the proximity of green spaces, Warren said. Bear in mind that the idea of building green corridors within cities is not new: Newark, New Jersey, may not be your idea of a garden spot, but Branch Brook Park winds through the heart of the city for 360 acres, and next month the largest collection of cherry blossom trees in the United States will be in flower there.

Plant for Wildlife

If you’ve got a local species you’re worried about, plant the species it needs to breed or feed. Monarch butterflies, for instance, require milkweed. Birds love oak trees (because they’re home to so many juicy caterpillars). If you happen to live in the Northeast, a guide published by The New York Times this week is useful: Bayberries for yellow-rumped warblers and black-eyed Susans for goldfinches are among the recommended plantings. Wherever you live, native plants are the key ingredient for native species. Avoid the exotics, especially the ones, such as barberry and purple loosestrife, that spread rapidly and wreak havoc on surrounding ecosystems. “Cities are a nexus for introduction” of invasive species, said Paige.

Invasive animals are also a problem, especially when pet owners do what they think is the humane thing by setting exotic species free. Burmese pythons are currently decimating the native mammal populations in the Florida Everglades.

Make Buildings Bird-Friendly

Cities can be rough for birds. In New York City alone, 90,000 birds die each year from flying into glass windowpanes that are invisible to their eyes. A 2014 paper estimated that across the United States, between 365 million and a billion birds may die from collisions with buildings each year. For ways to prevent your house from contributing to the problem, check recommendations in a report from the American Bird Conservancy. Some cities have also begun adopting bird-friendly building guidelines, as San Jose, California, did last week. A program called “Lights Out” has also been gaining traction in some cities. In the spring and fall, when many birds migrate, the bright lights from buildings can disorient them. Building owners in Boston, Chicago, Minneapolis, New York, and other cities have voluntarily agreed to turn off some or all lights at night. One incidental benefit: lower electric bills.

Get Educated

Outdoor cats are major bird killers. In many cities, one attempt to control the problem, called “Trap-Neuter-Return,” or TNR, has gained popularity among people who are unwilling to euthanize unwanted cats. But it doesn’t really work. If you’re a cat owner, spay or neuter your cat and keep it indoors. Work to outlaw feral cats in public parks and green spaces. They are just subsidized death squads for wildlife.

Cities also need to educate residents about how to live side by side with wildlife, because the wildlife is showing up, even uninvited. Los Angeles has mountain lions, and Berlin now has 4,000 wild boars. When New York City realized that it has well-established coyote populations in several city parks, the city made plans to post fliers and hand out cards listing “Five Easy Tips for Coyote Coexistence,” including the cardinal rule of keeping wildlife wild: Don’t feed the animals. In Bakersfield, California, the tiny San Joaquin kit fox is an endangered species, and it likes to den under sidewalks and beneath schools. The California Department of Fish and Game includes information about the foxes as part of its “Keep Me Wild” campaign. Among the suggestions: Pet food should stay indoors, to avoid feeding wildlife even accidentally.

Look Beyond City Limits

Even the roads connecting a city to the outside world can become wildlife habitat. By changing the timing and frequency of mowing roadside margins, some forward-thinking highway departments in Iowa, Florida, and a few other states are giving a break to ground-nesting birds, flowering plants, and pollinators. Roadside margins and even power transmission corridors can connect the fragmented habitat on the fringes of cities.

Though conservationists have tended to write off these “wastelands,” a new study published last month in the journal Animal Conservation found that some ground-nesting grassland birds around Chicago actually fledged more offspring when nesting near housing or other urban developments.

Take Action in Your Community

Lobby local building and zoning authorities to include wildlife-friendly provisions in their standard requirements. Last week the National Wildlife Federation named its "top ten cities for wildlife." If your city’s not on the list (hello Boston, Chicago, and Seattle!) find out why not and what your city could be doing better. Some cities are already asking any new development to include enough plantings and porous surfaces to handle all stormwater runoff on site. So why is Petco, Walmart, or Home Depot able to build in your community without setting aside a certain percentage of its parking area as green space?

When your city is debating how to prepare for climate change and rising sea levels, why not insist that saltmarsh buffer areas get equal consideration with seawalls? Those marshes incidentally benefit migrating shorebirds. (The seawalls only benefit contractors.)

Finally, we need an urban biodiversity index, so cities can start to benchmark their wildlife-friendliness against other cities of comparable size and begin to trade ideas for doing better. In fact, many cities worldwide are already adopting such an index pioneered by Singapore. Is there any reason this should not be coming to your neighborhood soon?

Geoffrey Giller contributed reporting for this column.