Highland Guan is a pheasant-sized and sexually dimorphic member of the family Cracidae. The species occurs mainly in cloud and pine-oak forest in the highlands of the southern Mexican states of Oaxaca and Chiapas, and in the Central American countries Guatemala, El Salvador, Honduras, and Nicaragua. Highland Guan is locally common, which is obvious only during the first part of the breeding season from February to April, when males emit a loud and far-carrying whistle which is often followed by a rattling sound produced by vibration of wing feathers while gliding between perches. The guans are rather silent outside the breeding season. They are shy and not easy to see. Nests are placed in the forest under and midstory, and sometimes on ground. The female incubates two white eggs alone. Foraging Highland Guans use all forest strata; they pluck a variety of fruit from the understory to the upper canopy, and pick up fallen fruit from the forest floor. Highland Guan is classified as Vulnerable mainly because of an ongoing loss of habitat. In addition to the standardized English common name Highland Guan (AOU 1998), a variety of names were used in earlier publications, such as Black Chachalaca, Black Penelope, Black Penelopina, Black Pajuil, and Little Guan (Salvin and Godman 1897-1904, Dickey and van Rossem 1938, Eisenmann 1955, Andrle 1967, Land 1970, Davis 1972, Blake 1977, Rowley 1984). The recent introduction of yet another name, Mountain Guan (Renner 2005) appears redundant. The most commonly used local Spanish names for Highland Guan are cayaya, pasha, gallina de monte, pava pajuil, and chachalaca negra (González-García et al. 2001; K. Eisermann, personal observations).