This EBA corresponds to the Western Domain of the Western Malagasy Region (a biogeographic region recognized by White 1983) in Madagascar, where the characteristic vegetation is seasonally dry deciduous forest.

The boundary of the EBA includes all remaining patches of deciduous forest, which occur on various distinctive rock types, largely below 800 m, from Antsiranana in the north to Morombe in the south-west; forest cover is based on satellite imagery of the vegetation taken between 1972 and 1979, these data being simplified and interpreted by Du Puy and Moat (1996) from Faramalala (1988, 1995).

In the north-west, the EBA is bisected by the so-called Sambirano Domain which is treated here as part of the East Malagasy wet forests (EBA 094; see that text), as is the Montagne d'Ambre Massif in the far north. On its western boundary, the EBA is skirted by the West Malagasy wetlands (EBA 096), which also intersects it along rivers and around inland lakes, overlapping in some places.

All the restricted-range species are forest birds and most are very local in distribution, e.g. Xenopirostris damii which is known from only two sites (Ankarafantsika and Analamera), and Phyllastrephus apperti which is recorded from just one forest complex (including the Zombitse and Vohibasia forests).

Mesitornis variegata is treated as endemic to this EBA but has one anomalous record in the East Malagasy wet forests (EBA 094). Coua coquereli and Philepitta schlegeli also occur in the Sambirano Domain (EBA 094), but their core ranges lie in the western dry forests. Thamnornis chloropetoides and Newtonia archboldi occur only in the extreme south of this EBA, the majority of their ranges falling within the South Malagasy spiny forest (EBA 097).

Benson's Rock-thrush Monticola bensoni was thought to breed on the Isalo Massif (Secondary Area s049) and in a few sites in the East Malagasy wet forests (EBA 094), dispersing to the western lowlands of the present EBA in winter-but breeding populations have recently been found west to Ankazoabo (S. M. Goodman in litt. 1996).

Estimates of the surface area of the remaining western dry forests vary from less than 12,000 km² to less than 20,000 km² (Smith et al. 1991a, Du Puy and Moat 1996; see also Nelson and Horning 1993), although misclassification of forest and inaccurate boundaries can result in wide margins of error (Hawkins 1994). Whatever the exact figures, it is certain that much of the dry deciduous forest within the boundaries of this EBA has been replaced by bush, wooded savanna and sterile grassland.

The extent to which man is responsible for these habitat changes is uncertain, as climatic changes resulting in desiccation over the last 2,000 years (since settlement) may also have contributed to modifications of the native vegetation (Burney 1995; see also Langrand and Goodman 1995). Nevertheless, forest has unquestionably been destroyed by man over the last 50 years and the main threats today come from subsistence cultivation involving the felling and burning of forest for maize-growing, commercial logging followed by fire and/or cultivation, and exploitation for charcoal and firewood (Jenkins 1987, A. F. A. Hawkins . 1995).

Three of the EBA's endemic species are classified as threatened on account of their small and declining ranges. Although protected areas appear to provide fairly good protection of the forest environment (Nicoll and Langrand 1989), and there are several strict nature reserves and special reserves in this EBA representing c.15% of extant forest, this protection is often nominal (Hawkins 1994). Du Puy and Moat (1996) calculate that only 9% of western forests are well protected, and note that many of the reserves are in areas of Mesozoic limestone where highly eroded limestone karst and pinnacles (known as 'tsingy') make access extremely limited and are an effective natural protection against overexploitation, burning and cattle-grazing; they suggest that protection of vegetation on other rock types should be carefully examined. In addition, the pressures on the dry forests are increasing very rapidly, and conservation action in this EBA should thus be viewed as a major priority for Madagascar (A. F. A. Hawkins verbally 1997).

Two key forests were identified by Collar and Stuart 1988 (see also Collar et al. 1987): the Ankarafantsika Strict Nature Reserve (which provides some protection for Mesitornis variegata and Xenopirostris damii) and the Zombitse Forest (important for Phyllastrephus apperti), the latter the subject of a NORAD-funded WWF project to establish it and Vohibasia Forest as a national park. Other important sites include Analamera Special Reserve (which protects the second known site for Xenopirostris damii and also holds Mesitornis variegata), Menabe Forest (including Andranomena Special Reserve and Kirindy Forest, a logging concession which is being exploited sustainably) and Analabe Private Reserve (A. F. A. Hawkins verbally 1996).