Females are similar but slightly smaller than male.
The Guam Rail is a secretive, flightless, territorial species that is most easily observed as it bathes or feeds along roadsides or field edges. The call is a loud, piercing whistle or series of whistles, usually given by two or more birds in response to a loud noise, the call of another rail, or other disturbances. Though individuals will respond almost invariably to the call of another rail, the species is generally silent. The rail is one of the few native birds of Guam that is found more frequently in scrubby second growth or mixed forest than in uniform tracts of mature forest, and might have been more abundant after the arrival of man than before. It is an omnivorous feeder but appears to prefer animal over vegetable food.