The roadrunner is a large, slender, black-brown and white streaked ground bird with a distinctive head crest. It has long legs, strong feet, and an oversized dark bill. The tail is broad with white tips on the three outer tail feathers. The bird has a blank patch of skin behind each eye; this patch is shaded blue proximally to red distally. The lesser roadrunner is slightly smaller, not as streaky, and has a smaller bill. The bird is terrestrial; although capable of flight, it spends most of its time on the ground. During flight, the wings are short and rounded and reveal a white crescent in the primary feathers. Roadrunners and other members of the cuckoo family have zygodactyl feet (two toes in front and two toes in back). Roadrunners can run at speeds of up to 20 miles per hour (32 km/h) and generally prefer sprinting to flying. Roadrunners will fly to escape predators.