Scaly Ground-roller Geobiastes squamiger


Taxonomic note
Geobiastes squamiger (del Hoyo and Collar 2014) was previously placed in the genus Brachypteracias. Gender agreement of species name follows David and Gosselin (2002b).

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - A3c

Red List history
Year Category Criteria
2016 Vulnerable A3c
2012 Vulnerable A3c
2008 Vulnerable A3c
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Land-mass type - shelf island
Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 135,000 medium
Number of locations 11-100 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 1500-7000 poor estimated 1999
Population trend Decreasing medium suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 30-49 - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations 2-100 - - -
Largest subpopulations - - -
Generation length (yrs) 5.6 - - -

Population justification: The population is estimated to number 2,500-9,999 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated extent of occurrence is likely to be occupied. This estimate is equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals. The true population size may lie at the upper end of this estimate, as while the species is described as uncommon it can be easily overlooked and so nay be more common than has previously been believed (Collar and Stuart 1985).

Trend justification: Modelling the possible effects of climate change have shown that this species's ecological niche may decline by c.45% due to climate change over the 50 year period from 2000 to 2050 (Andriamasimanana and Cameron 2013). Assuming a linear decrease, this would equate to a c.17.5% decline in its ecological niche over its next 3 generations, from climate change alone. Habitat loss and degradation due to forest conversion have led to a suspected moderate decline in population over the last 3 generations. In line with all of these factors, the rate of decline is expected to become rapid over the next 3 generations (c.30-49% decline).

Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Madagascar N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Madagascar Daraina Forest
Madagascar South Anjanaharibe Special Reserve and extension
Madagascar Marojejy National Park
Madagascar Masoala National Park
Madagascar Anjanaharibe Classified Forest
Madagascar Upper Rantabe Classified Forest
Madagascar Mananara-North National Park
Madagascar Ambatovaky Special Reserve
Madagascar Zahamena National Park and Strict Reserve
Madagascar Betampona Strict Nature Reserve
Madagascar Sihanaka Forest
Madagascar Mantadia National Park and Analamazaotra Special Reserve
Madagascar Andohahela National Park - Section I
Madagascar Tsitongambarika NPA
Madagascar Ranomafana National Park and extension
Madagascar Andringitra National Park
Madagascar Vondrozo Classified Forest NPA
Madagascar Midongy South National Park
Madagascar Tsaratanana-Marojejy Corridor NPA (COMATSA)
Madagascar Masoala National Park - Section II
Madagascar Zahamena-Mantadia SAPM
Madagascar Ranomafana North
Madagascar Masoala National Park - Section III
Madagascar NAP Corridor Ambositra-Vondrozo (COFAV) (part of)
Madagascar Anjanharibe-Sud - Marojejy Future Proposed Protected Area
Madagascar Ambositra-Vondrozo Corridor NPA (COFAV)
Madagascar Ankeniheny Zahamena Corridor NPA (CAZ)
Madagascar Daraina (Loky - Manambato) SAPM
Madagascar Makira Natural Park
Madagascar Fandriana-Marolambo Forest Corridor NPA (COFAM)

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major resident
Altitude 0 - 1000 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Shifting agriculture Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation, Ecosystem conversion
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Species mortality
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation, Ecosystem conversion
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Future Whole (>90%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Canis familiaris Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Species mortality

Recommended citation
BirdLife International (2020) Species factsheet: Geobiastes squamiger. Downloaded from on 23/09/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from on 23/09/2020.