A flock of wild turkeys (crossing the street below the bridge) in a ravine of Pittsburgh's Schenley Park. Photo courtesy of Timothy Wisniewski.
Pittsburgh is characterized by steep hillsides (hence the city's famous inclines) and undeveloped ravines, which act as wooded wildlife corridors for critters moving into the city from the rural outskirts. Since passage of the Clean Water Act, animals like beavers, otters, and bald eagles have moved in to reinhabit the banks of the Allegheny and Monongahela Rivers. As in any city, humans' backyards, garbage, and feeders, plus an absence of predators, attract other mammals, like rats, coyote, and deer.