Although the peregrine falcon, Falco peregrinus, is still rare in Utah, it has become much more abundant throughout its range in recent years. The widespread use of the pesticide DDT in the 1940s, 1950s, and 1960s caused a drastic reduction in peregrine falcon numbers (and in the numbers of other raptor species) throughout North America. It was eventually determined that DDT was moving up the food chain and causing raptors to lay thin-shelled eggs that would often break during incubation. DDT was banned in early 1970s, which allowed the peregrine falcon to start its recovery. By August 1999, the peregrine falcon had recovered to the point that it was removed from the Federal endangered species list.
Birds captured in flight are the main food item for the peregrine falcon. The species is distributed very widely, breeding in a variety of habitats on every continent except Antarctica. Eggs are incubated for about one month and the average clutch size is four. The peregrine falcon is the world's fastest bird, capable of attaining speeds of over 200 miles per hour.