This poorly explored EBA includes various mountain ridge-tops: those of the Cordillera del Condor on the border of south-east Ecuador and northern Peru, and in northern Peru the isolated Cordillera de Colán, the northernmost end of the Cordillera Oriental, and the isolated mountains east of the Mayo river (on the San Martín–Loreto department boundary); the range of one endemic species extends the boundaries of the EBA east of the Cordillera del Condor into the middle Marañón valley in Peru’s northern Amazonas department. Distributionally, the species defining the EBA are poorly known, so the boundaries of the area cannot be more precisely delineated than the various mountain ranges described above. Though separated by habitat preferences, the ridge-top forest restricted-range species overlap with the ranges of some of the restricted-range species from the North-east Peruvian cordilleras (EBA 049) in the northernmost part of the Cordillera Oriental and the Cordillera de Colán.

Native vegetation of this EBA is the humid, often stunted evergreen forest on ridge-tops (ridge spurs projecting from the main mountain chain), primarily between 1,000 and 2,450 m. The highly specialized stunted elfin or cloud forest on such ridges is generally the result of the drenching afforded by the moisture-laden prevailing easterly winds, the exposed nature of the situation and, quite often, outcrops of mineral-poor soil (Collar et al. 1992).

Most of the restricted-range species occur in humid, subtropical to lower temperate zone, stunted ridge-top forest, with forest edge and bushy areas adjacent to forest also being inhabited by some of the birds. Wetmorethraupis sterrhopteron has a distribution slightly disjunct from the other species, and occurs lower down, at 600-800 m, where it inhabits mature humid forest on mountain slopes; however, it is probably best treated in this EBA due to suspected sympatry with other endemics on the Cordillera del Condor (Collar et al. 1992, T. A. Parker in litt. 1991).

This area of southernmost Ecuador and northern Peru has only recently been explored; thus, five of the six endemics have been discovered since 1975, and Wetmorethraupis sterrhopteron was first found in 1963 (Collar et al. 1992; also Fitzpatrick et al. 1977, Graves et al. 1983). Because of the general paucity of distributional information, the limits of the various species in this group, and how they relate to those species in the North-east Peruvian cordilleras, is poorly known. However, the North-east Peruvian cordillera birds appear to be confined to the main mountain range at slightly higher altitudes (1,900-3,700 m), with the restricted-range species from this EBA (Xenoglaux loweryi, Grallaricula ochraceifrons, Hemitriccus cinnamomeipectus and Henicorhina leucoptera) overlapping with them but restricted to the stunted, lower-altitude forest on the ridge spurs.

Vegetation in this EBA is generally in a reasonable state, although deforestation is increasing, with areas adjacent to the EBA having suffered particularly badly in recent decades (Collar et al. 1992). Recent surveys of the northern end of the Cordillera de Colán (within the EBA) found an alarmingly high deforestation rate, with most of the forest in this area already gone, and what remains being rapidly cleared for cash-crops, particularly marijuana and coffee (Barnes et al. 1995).

Three of the endemics are considered threatened, partly due to the uncertain status of the habitat in many of the areas, where even limited deforestation potentially threatens species with such restricted ranges and specific needs. All the ridge-top areas are of critical importance, especially those projecting from the northern part of the Cordillera Oriental and the isolated Cordillera de Colán (which are the only known localities for Xenoglaux loweryi and Grallaricula ochraceifrons) and the area east of the Mayo river (the only known area for Herpsilochmus parkeri). Another more-widespread threatened bird known from this EBA is Military Macaw Ara militaris (Vulnerable).

Nine Key Areas have been identified in this EBA for the conservation of threatened species, two in the Cordillera del Condor in Ecuador and the remainder in Peru. None of these Key Areas is currently protected, and the EBA as a whole remains one of the most biologically important but least protected EBAs in the Americas (IUCN 1992a, Wege and Long 1995).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Andean ridge-top forests. Downloaded from https://datazone.birdlife.org/eba/factsheet/50 on 22/11/2024.