Problem wildlife” has become one of the defining difficulties of suburban life, like crabgrass and boredom. Stories of raccoons in the attic, deer in the garden, and geese on the soccer field regularly appear in the media, and every suburbanite I meet can enrich the growing stock of anecdotes with stories of his own.
Gehrt and his assistant, Suzie Hatten, a graduate student from the University of Missouri, have been monitoring raccoon populations at six sites in the Chicago area, and what their numbers show is that sprawl creates large increases in raccoon populations. Natural areas surrounded by farms have far fewer animals than natural areas surrounded by suburbs.
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The critical difference in the suburban sites may be the existence of year-round food sources in the garbage cans and Dumpsters of homes and businesses. Combine that with the presence of the preserve as a refuge and you have a recipe for major raccoon abundance.
The other big worry is birds. During the nesting season raccoons are heavy predators on bird nests, eating both eggs and young. As agile climbers, raccoons can go after both ground nesters and tree nesters. A number of studies have shown that predation on nests is quite heavy in suburban areas where raccoon populations–and the populations of other nest predators–are high. In one study predation reached 100 percent; every single nest was raided. Gehrt intends to put out some artificial nests this spring to begin the job of measuring raccoon predation. We also need general studies of nesting success in this region like those carried out elsewhere in the state by Scott Robinson and Jeff Brawn of the Illinois Natural History Survey.
