Cryptic Warbler Cryptosylvicola randrianasoloi


Justification of Red List Category
Although this species may have a restricted range, it is not believed to approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Population justification
The global population size has not been quantified, but the species is described as locally common (del Hoyo et al. 2006).

Trend justification
The population is suspected to be in decline owing to ongoing habitat destruction.

Distribution and population

This species was discovered in 1992 in the Maromiza Forest, close to the Réserve Spéciale d'Analamazaotra in the central area of the eastern rain forest of Madagascar (Goodman et al. 1996). It has subsequently been found to be restricted to, but relatively widespread in, the eastern part of the island from Anjanaharibe-Sud in the north to Andohahela in the south, being recorded from eight localities including six nature reserves, although it may well occur in areas to the north and south of its currently known range (Goodman et al. 1996).


The species would appear to prefer evergreen, humid rain forest between 900-2,100 m, but is found in primary forest, montane forest, along steep ridges, areas of bamboo and also in altered habitats including disturbed and degraded forest, exotic plantations next to native forest and forest fragments (Goodman et al. 1996, Morris and Hawkins 1998). In montane forest it favours areas dominated by Podocarpus, and in ridge-top sclerophyllous forest it favours areas where epiphytic moss and lichens are plentiful (Goodman et al. 1996). It inhabits the canopy and sub-canopy of trees and shrubs from 2-25 m but is found most often between 3-15 m, sally-gleaning insects from foliage, twigs and branches (Goodman et al. 1996). It has been recorded on numerous occasions in mixed species flocks (Goodman et al. 1996). The breeding season is October-December; one nest examined contained three eggs and family groups observed in November have comprised up to four individuals (Goodman et al. 1996). Records of the species in degraded and altered habitats indicate that it is tolerant of disturbance (Goodman et al. 1996).


The principal threat to the eastern humid forests is from slash-and-burn cultivation by subsistence farmers, resulting in progressively more degraded regrowth and leading eventually to bracken-covered areas or grassland (Stattersfield et al. 1998).


Text account compilers
Ekstrom, J., Fisher, S., Harding, M., Butchart, S.

Recommended citation
BirdLife International (2023) Species factsheet: Cryptosylvicola randrianasoloi. Downloaded from on 01/02/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 01/02/2023.