Which bird flies the fastest?

peregrine falcon, the fastest bird on Earth
   The peregrine falcon (Falco peregrinus), when diving up to 270 miles (435 km) per hour after crow, pigeon, blackbird, or duck, is the fastest. The free-falling falcon kills its target or knocks it unconscious and then circles back and catches the prey as it plunges toward the ground. The falcon's cruising speed when not after prey is about 55 miles per hour. The bird's range extends throughout North America, especially in vast open areas, and around islands, rivers, and cliffs.
   In the 1950s and 1960s, when the pesticide DDT was widely used, the peregrine falcon population nose-dived; by 1972 it had been reduced by 90 percent in the United States, to thirty-nine known pairs. After a ban on the use of DDT and a very successful recovery program, in 1999 the peregrine falcon was officially removed from the endangered species list.