A huge, ground-dwelling cuckoo. Streaky brown overall with a very long tail and short, shaggy crest. Surprisingly iridescent in good light, with purple and green tones on wings and tail. Usually seen on the ground in dry desert habitats with patches of thick vegetation; sometimes perches on fences or rocks, especially when singing. Runs swiftly after large insects, lizards, and other prey. Unmistakable in most of range; overlaps locally with Lesser Roadrunner in west Mexico. Greater has more streaking on the throat and center of breast, instead of clear buffy on Lesser. Listen for very low-pitched cooing song.