Data Zone
Justification of Red List category
This species has a large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence under 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). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (under 10,000 mature individuals with a continuing decline estimated to be over 10% in ten years or three generations, or with a specified population structure). 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 (over 30% decline over ten years or three generations). 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). This species is considered to have a high dependency on forest habitat, and tree cover is estimated to have declined by 15.4% within its mapped range over the past 10 years (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). It is therefore tentatively suspected that this rate of cover loss may have led to a decline of between 1-19% in the species' population size over the same time frame, with a best estimate of reduction being 15-19%.
Trend justification
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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
Rutherford, C.A.
Recommended citation
BirdLife International (2024) Species factsheet: Cryptic Warbler Cryptosylvicola randrianasoloi. Downloaded from
https://datazone.birdlife.org/species/factsheet/cryptic-warbler-cryptosylvicola-randrianasoloi on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.