Birds make their living in a number of ways. There are even a few bird species that specialize on other birds. The Peregrine Falcon is one such species. It hunts by swooping down on other bird species, ranging from warblers to gulls. These other birds are often out of luck, as Peregrine Falcons reach speeds of up to 200 km/h! Although birds are a profitable food source, Peregrine Falcon's high position in the food chain has resulted in the accumulation of high levels of the pesticide DDT in Peregrine body tissues. This chemical caused eggshell thinning, pushing the Peregrine falcon to the brink of extinction. Fortunately, as a result of the banning of DDT and bird conservation efforts, populations have recovered across North America, including Southern Quebec, where numbers have increased from 0 pairs to 13 pairs during the last 20 years. Nests are found primarily on cliffs, but also in trees, on the ground, and even on urban bridges and city skyscrapers. In fact, Peregrines can be found nesting in downtown Montreal and Quebec, as well as 25 other cities across North America.