We've had a problem with rabbits in downtown Chicago, they were breeding like, well, rabbits and doing very expensive damage to the landscaping in the parks.
Here's an article if anyone is interested:
http://articles.latimes.com/2007/aug/05/news/adna-rabbits5Quote from the article:
The advent of leash laws and the lack of other predators allowed the rabbits to thrive. Coyotes that might normally cull the bunny population were chased, captured and removed by the city’s animal control officers. By 2001, the bunny population had boomed, and the rabbits had eaten their way through $100,000 worth of landscaping in Grant Park. Other cities around the country, including Miami, Detroit and Hartford, Conn., struggled with similar invasions.