For Urban Animals, Cities Imitate Nature

Like animals in the wild, urban creatures require habitats that will satisfy their need for food and water, a place to rest and sleep, cover for rearing young, and protection from predators. Wildlife ecologist Larry W. VanDruff of the State University of New York's College of Environmental Science and Forestry in Syracuse has found that metropolitan areas contain three categories of habitat. He describes them as the central city core, the mainly residential suburbs radiating out from the core, and, farthest out, a fringe area that is relatively free of development. VanDruff emphasizes that these zones have no sharply defined borders. The landscape changes gradually from the built-up inner city out to the outlying areas where farm fields and forests prevail.

All three habitat areas provide rich food resources. In addition to finding their natural foods, animals can supplement their diet with pickings from a variety of sources, ranging from garbage cans to garbage dumps and landfills. Metropolitan areas have plenty of water as well, in reservoirs, park lakes, birdbaths, fountains, gutters, and reflecting pools. In fact, the food and water resources of urban communities offer animals a greater variety of habitats than was available there prior to human habitation.

Cities also alter the local climate. Heat produced by houses, apartment and office buildings, factories, and automobiles makes the city warmer than outlying areas. Suburbs are cooler than the central city core, but even there, heat generated by homes and automobiles makes them significantly warmer than wild places. The warmth of these so-called microclimates improves the survival rate of many urban species.

Urban animals share several common characteristics. First, they are adaptable. As their natural habitat disappeared, they changed their behavior to fit the new conditions of the urban environment. Second, urban species tend to be opportunists and omnivores—that is, they are willing to eat a variety of foods, both animal and plant. In addition, they are intelligent, some extremely so. And finally, urban species have adjusted to the presence of people. They have learned to recognize which kinds of human behavior pose a threat and which do not.