This EBA includes the mountains of south-east Mexico (east of the Isthmus of Tehuantepec, EBA 014), Guatemala, El Salvador, Honduras and north-central Nicaragua. The topography is especially complex in central Guatemala, with several volcanoes rising above 4,000 m. Some of the mountain ranges, such as the Sierra Madre de Chiapas, run parallel to the Pacific coast and so lie adjacent to the North Central American Pacific slope (EBA 017).

The principal habitats are various types of humid montane and lower montane forest: at 600-1,400 m lower montane (semi-deciduous) forest; at 1,400-2,500 m humid montane forest and (on the wettest slopes) cloud forest, both dominated by evergreen oaks; at 2,500-3,000 m pine-oak and cypress forests; and above 3,000 m fir forest dominates. In parts receiving less rain there are more deciduous formations, such as tropical deciduous forest and oak scrub. The montane forests of north Central America are noted for high levels of plant endemism (Breedlove 1981, Rzedowski and Calderón de Rzedowski 1989).

With 20 extant restricted-range species, these highlands hold more than any other of the north Central American and Mexican EBAs. The majority of the birds are found above 1,500 m in the pine-oak and montane forests, some (e.g. Atthis ellioti, Melanotis hypoleucus, Cyanocorax melanocyanea) being associated with forest edge, secondary growth and scrub areas. Xenotriccus callizonus and Icterus maculialatus, which occur mainly in semi-deciduous forest, are found in drier inter-montane areas of the EBA down to 500 m (but do not occur in the North Central American Pacific slope [EBA 017]).

Most species are distributed throughout the EBA but Oreophasis derbianus, Otus barbarus, Tangara cabanisi, Ergaticus versicolor and Carduelis atriceps occur only in the western part (Mexico and Guatemala). Podilymbus gigas has the most restricted distribution being endemic to Lake Atitlán in south-west Guatemala. The two mountain-gems are allospecies, both confined to this EBA, Lampornis viridipallens being found from Mexico to eastern Honduras, L. sybillae in interior eastern Honduras to north-central Nicaragua.

The pine-oak forest within this EBA is disappearing rapidly through logging, firewood-gathering, uncontrolled burning, agricultural expansion and bark-beetle epidemics that are exacerbated by degradation from logging, grazing and burning. The montane forests are especially affected at 1,000-1,800 m by the growing of coffee without shade trees and by firewood-gathering. New roads continue to open up areas for further human exploitation (Dinerstein et al. 1995). The current civil war in Chiapas has caused accelerated deforestation of pine–oak areas in the Altos de Chiapas (P. J. Bubb in litt. 1997).

Two of the restricted-range species are considered threatened, and a further five Near Threatened. Most restricted-range species are found in degraded forest, hence the low number threat-listed in relation to the high number confined to this EBA. However, Oreophasis derbianus is threatened by a combination of extensive and intensifying deforestation and continuing hunting pressure (Collar et al. 1992). Tangara cabanisi is restricted to a small part of this EBA in the Sierra Madre de Chiapas and adjacent Guatemala, principally on its Pacific slope at 1,000-1,700 m; it is threatened because its habitat is prime land for coffee cultivation (Heath and Long 1991).

The winter quarters of the threatened restricted-range Golden-cheeked Warbler Dendroica chrysoparia fall within the highlands of this EBA (it breeds in Edwards plateau, Secondary Area 006)-but there are few records, probably due to the paucity of observers, especially in Guatemala, El Salvador and Honduras; the only area with regular sightings (46 during 1990-1992) is around San Cristóbal de las Casas in central Chiapas, Mexico (Vidal et al. 1994). Atitlán Grebe Podilymbus gigas, estimated to have a population of 210 in 1973, apparently became extinct on Lake Atitlán during the 1980s, owing probably to replacement by or hybridization with the widespread Pied-billed Grebe P. podiceps.

Wege and Long (1995) identified 14 Key Areas for this EBA's threatened restricted-range species (two endemics and one wintering) (see also Barker 1990). More surveys are needed in most of these areas, such as those identified for Dendroica chrysoparia (e.g. Volcán de San Salvador, El Salvador; La Esperanza and Cerro Cantoral, Honduras) where the records are over 20 years old, and those for Oreophasis derbianus along the volcano peaks in Guatemala and south-east Chiapas. Several Key Areas are protected, including, in Mexico, the El Triunfo Biosphere Reserve and Lagunas de Montebello National Park; and, in Guatemala, Sierra de las Minas Biosphere Reserve and Atitlán National Park. El Triunfo is especially important as it holds a significant proportion of the range of Tangara cabanisi and important populations of O. derbianus, as well as the enigmatic Resplendent Quetzal Pharomachrus mocinno-and indeed most of the restricted-range species of this EBA.

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: North Central American highlands. Downloaded from https://datazone.birdlife.org/eba/factsheet/14 on 23/11/2024.