The EBA is located in the southern half of the Baja California peninsula, and falls within the Mexican states of Baja California Norte and (principally) Baja California Sur. The main mountain range of the EBA is the Sierra de la Giganta/Sierra Victoria (rising to c.1,700 m) along the eastern side of the peninsula, with the less extensive Cape Mountains in the Sierra de San Lázaro (to 2,400 m) in southern Baja California Sur.

With low rainfall and high mean annual temperatures, especially in the summer months, the dominant vegetation is arid and desert scrub on the west coast, dry forest on the eastern slopes, and coniferous forests and pine-oak forests confined to the higher altitudes of the mountains. The peninsula is very important floristically: 25% of its 2,700 plant species are endemic, as are 20 genera (Rzedowski 1993).

Two subspecies of Geothlypis beldingi are recognized: the nominate form is restricted to southern Baja California Sur and goldmani to central Baja California Sur. This species is confined to freshwater marsh areas, especially those fringed with generous vegetation cover, whereas Hylocharis xantusii is found in a variety of habitats.

There are potentially more restricted-range species occurring in this EBA. Baird's Junco Junco bairdi, which is confined to the Cape Mountains is traditionally (and here) considered conspecific with the widespread Yellow-eyed Junco J. phaeonotus, but is treated as a full species by Howell and Webb (1995a); it is a fairly common resident of arid to semi-arid oak and pine-oak forest at 1,200-1,900 m. Cape Pygmy-owl Glaucidium hoskinsii, which is endemic to the Sierra de San Lázaro and probably also Sierra de la Giganta, is usually treated under Mountain Pygmy-owl G. gnoma, but is considered to be an allospecies by Howell and Webb (1995a). It inhabits pine and pine-oak forest at 1,500-2,100 m and deciduous forest down to 500 m in winter. Conversely, a subspecies of American Robin, San Lucas Robin Turdus migratorius confinis, which is also endemic to the mountain pine forests of Sierra de San Lázaro, has been treated by some authorities as a distinct species, but is now considered a subspecies by all modern checklists and guides to the region.

Large areas of the EBA are uninhabited but southern Baja California is becoming ever more popular for tourism and recreational activities. The arid scrub desert on the western side of the EBA is being damaged by off-road vehicles, and illegal logging of boojum trees Idria columnaris, while the dry forests on the eastern side are threatened by agricultural expansion and grazing (Dinerstein et al. 1995).

Geothlypis beldingi is treated as threatened because the nominate race apparently survives at only one small marsh near San José, while goldmani remains common at just a handful of localities owing to the loss of its preferred habitat through drainage and drought.

The EBA does not have any protected areas. Although the El Vizcaíno Biosphere Reserve, one of the world's largest protected areas (more than 25,000 km²), is nearby in north-west Baja California Sur, the reserve falls outside the range of both Hylocharis xantusii and Geothlypis beldingi.

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Baja California. Downloaded from https://datazone.birdlife.org/eba/factsheet/3 on 23/11/2024.