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. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Critically Endangered | Endangered | Vulnerable |
---|---|---|
C2a(ii) | B1ab(ii,iii,v)+2ab(ii,iii,v); C2a(i,ii); D | B1ab(ii,iii,v)+2ab(ii,iii,v); C2a(i,ii); D1 |
Year | Category | Criteria |
---|---|---|
2021 | Critically Endangered | C2a(ii) |
2018 | Critically Endangered | C2a(ii) |
2016 | Critically Endangered | C2a(ii) |
2015 | Critically Endangered | C2a(ii) |
2013 | Critically Endangered | C2a(ii) |
2012 | Critically Endangered | C2a(ii) |
2011 | Critically Endangered | C2a(ii) |
2010 | Critically Endangered | C2a(ii) |
2009 | Critically Endangered | C2a(ii) |
2008 | Critically Endangered | |
2007 | Critically Endangered | |
2004 | Critically Endangered | |
2000 | Critically Endangered | |
1996 | Critically Endangered | |
1994 | Critically Endangered | |
1988 | Threatened |
Migratory status | not a migrant | Forest dependency | high |
Land-mass type | Average mass | - |
Estimate | Data quality | |
---|---|---|
Extent of Occurrence (breeding/resident) | 140 km2 | medium |
Area of Occupancy (breeding/resident) | 192 km2 | |
Number of locations | 1 | - |
Severely fragmented? | no | - |
Estimate | Data quality | Derivation | Year of estimate | |
---|---|---|---|---|
Population size | 130-1700 mature individuals | poor | estimated | 2020 |
Population trend | decreasing | poor | inferred | - |
Generation length | 7.1 years | - | - | - |
Number of subpopulations | 1 | - | - | - |
Percentage of mature individuals in largest subpopulation | 100% | - | - | - |
Population justification: Based on a range-size assumption of 100 km2, using density surface modelling and plot sampling extrapolations, the population was estimated to be between 347-4,578 individuals (Azevedo 2015). Assuming this species exists in the smallest area estimate of 55 km2 (Soares et al. 2020), the estimated population would therefore be roughly 190-2,500 individuals, which would roughly equate to 130-1,700 mature individuals.
The worst-case scenario of <200 individuals is not consistent with the number of ibises that hunters reported killing (Sampaio et al. 2016), however the best-case scenarios still produce very low population estimates.
Trend justification: The population is inferred to be declining as a result of ongoing hunting pressure (Sampaio et al. 2016). Hunting pressure is suspected to be high, but the resulting rate of decline is unclear. It may also be suffering habitat loss as a result of an oil palm plantation.
Country/Territory | Presence | Origin | Resident | Breeding visitor | Non-breeding visitor | Passage migrant |
---|---|---|---|---|---|---|
São Tomé e Príncipe | extant | native | yes |
Country/Territory | IBA Name |
---|---|
São Tomé e Príncipe | Parque Natural Obô de São Tomé e Zona Tampão |
São Tomé e Príncipe | São Tomé lowland forests |
Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
---|---|---|---|
Forest | Subtropical/Tropical Moist Lowland | major | resident |
Forest | Subtropical/Tropical Moist Montane | marginal | resident |
Wetlands (inland) | Permanent Freshwater Lakes (over 8ha) | suitable | resident |
Wetlands (inland) | Permanent Rivers/Streams/Creeks (includes waterfalls) | suitable | resident |
Altitude | 100 - 1000 m | Occasional altitudinal limits |
Threat (level 1) | Threat (level 2) | Impact and Stresses | |||||||
---|---|---|---|---|---|---|---|---|---|
Agriculture & aquaculture | Annual & perennial non-timber crops - Scale Unknown/Unrecorded | Timing | Scope | Severity | Impact | ||||
Past, Unlikely to Return | Majority (50-90%) | Rapid Declines | Past Impact | ||||||
|
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Agriculture & aquaculture | Annual & perennial non-timber crops - Small-holder farming | Timing | Scope | Severity | Impact | ||||
Future | Minority (<50%) | Very Rapid Declines | Low Impact: 5 | ||||||
|
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Biological resource use | Hunting & trapping terrestrial animals - Intentional use (species is the target) | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Rapid Declines | Medium Impact: 7 | ||||||
|
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Biological resource use | Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
|
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Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Cercopithecus mona | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Unknown | Unknown | ||||||
|
|||||||||
Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Civettictis civetta | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Unknown | Unknown | ||||||
|
|||||||||
Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Felis catus | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Unknown | Unknown | ||||||
|
|||||||||
Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Rattus rattus | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Unknown | Unknown | ||||||
|
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Natural system modifications | Dams & water management/use - Large dams | Timing | Scope | Severity | Impact | ||||
Future | Majority (50-90%) | Rapid Declines | Low Impact: 5 | ||||||
|
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Transportation & service corridors | Roads & railroads | Timing | Scope | Severity | Impact | ||||
Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
|
Purpose | Scale |
---|---|
Food - human | subsistence, national |
Recommended citation
BirdLife International (2024) Species factsheet: Dwarf Ibis Bostrychia bocagei. Downloaded from
https://datazone.birdlife.org/species/factsheet/dwarf-ibis-bostrychia-bocagei on 18/12/2024.
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 18/12/2024.