Birding in Boston – What Urban Birds Tell Us
By Elizabeth Deatrick
BU News Service
Birding in Boston is much more than just swan boats and the occasional pigeon––the city actually supports an enormous variety of bird species, and one scientist aims to find out why. Dr. Paige Warren, of the University of Massachusetts Amherst, has been studying urban birds and how and where they live. Recently, she has come to some surprising conclusions about what urban areas are best for birds––and what we can do to help both them, and ourselves.
In a recent lecture at Harvard’s Arnold Arboretum, Warren explained that the lives of urban birds are closely tied to social justice issues. The spread of lower-income neighborhoods in cities parallels declining bird populations––in part because poorer neighborhoods often have fewer full-grown trees, and therefore fewer attractive places for birds to live. Warren believes that, by studying how birds are attracted to urban green spaces, and how those green spaces can be improved and expanded, cities and towns can improve the lives of both people and birds.
Warren’s work focused on two cities: Phoenix, and Boston. Despite their radically different environments, the problems that have confronted birds in these two cities are similar: native habitats have been subsumed by lawns, houses, and other human-constructed landscapes.
But instead of disappearing from these environments, some birds––though not all––adapted quite well. These new “urban birds” were often generalists: they were not picky about what they ate. But there were limits: in Phoenix, Warren said, “The pigeons would just… stop at the desert [at the edge of the city]. They don’t go out there.”
Instead, more specialized birds took over around the edges, where green lawns were more scarce, and dry, xeriscaped yards that resembled the surrounding desert were more common. Warren acknowledges that this could be for a variety of reasons: either different kinds of birds are coming in from the desert, or xeriscaped yards are more likely to be owned by upper-class people, who can provide more varied kinds of food to their resident birds.
Thanks to a more temperate environment, Boston’s urban birds also prefer parks full of big trees with dense canopies, as well as large patches of undeveloped land. Warren cites the Emerald Necklace park system as an excellent urban bird habitat: it’s designed by and for humans, but it’s large, and has many old trees.
Are large green spaces the only solution for encouraging birds in cities? Warren is adamant that even small green areas can make a difference. “We were, frankly, not expecting to find anything,” she said, but explained that small patches of greenery, such as tree-lined streets or tiny parks, do attract more birds than the surrounding city, even if they don’t increase the variety of bird species. “In general,” said Warren, “every 150 square meters of greenery gets you one more species.”
These small green spaces, scattered throughout the city, may have an impact on more than birds: Warren is sure that urban greening projects can help with social justice issues, such as urban revitalization––and she’s not the only one thinking that way. Cornell’s Celebrate Urban Birds project, in collaboration with many other organizations across the country, works with lower-income communities to get people excited about their neighborhoods’ potential––both for their avian and human residents. Like Warren, Celebrate Urban Birds sees the greening of urban spaces as a path towards better cities.
“Because a lot of our participants don’t have land, we have a list of plants that grow well in containers, and that attract birds,” says Karen Purcell, the project leader for Celebrate Urban Birds. “If there’s a good habitat for birds, and the birds are thriving, it’s good for people as well.”