The northernmost representative of a large family of terrestrial birds, Thicket Tinamou occurs from northern Mexico south to southern Costa Rica. This species has two distinctive groups of populations. Along the Pacific lowlands of Mexico from Sinaloa to Guerrero is a subspecies that is gray below and whose male has an unbarred back. From Tamaulipas and the Yucatan Peninsula to the dry forests of northwestern Costa Rica are forms that are cinnamon below and whose males are barred above. Females of all populations are barred above. All Thicket Tinamous also have red legs. Thicket Tinamou occurs from arid woodlands near sea level to approximately 1800 m where it inhabits moist oak woodlands. Although large (length 29 cm), Thicket Tinamou generally remains hidden among dense shrubs, vine tangles, and impenetrable thickets of terrestrial bromeliads, so is usually detected by its far-carrying, mellow, quavering whistle.