Data Zone
Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
| Critically Endangered | Endangered | Vulnerable |
|---|---|---|
| - | A2b; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i) | A2b; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i); D1 |
| Year | Category | Criteria |
|---|---|---|
| 2021 | Endangered | A2b; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i) |
| 2016 | Critically Endangered | B2ab(i,ii,iii,iv,v) |
| 2015 | Critically Endangered | B2ab(i,ii,iii,iv,v) |
| 2012 | Critically Endangered | B2ab(i,ii,iii,iv,v) |
| 2009 | Critically Endangered | B2a+b(i,ii,iii,iv,v) |
| 2008 | 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 |
Land-mass type - continent |
Average mass | - |
| Estimate | Data quality | |
|---|---|---|
| Extent of Occurrence breeding/resident (km2) | 130 | medium |
| Extent of Occurrence breeding/resident (km2) | 20 | good |
| Number of locations | 3 | - |
| Severely Fragmented | - |
| Value | Data quality | Derivation | Year of estimate | |
|---|---|---|---|---|
| No. of mature individuals | 250-999 | good | estimated | 2010 |
| Population trend | Decreasing | poor | inferred | - |
| Decline (3 years/1 generation past) | - | - | - | |
| Decline (5 years/1 generation past) | - | - | - | |
| Decline (10 years/1 generation past) | - | - | - | |
| Decline (10 years/3 generation future) | - | - | - | |
| Decline (10 years/3 generation past and future) | - | - | - | |
| Number of subpopulations | 3 | - | - | - |
| Percentage in largest subpopulation | 1-89 | - | - | - |
| Generation length (yrs) | 3.86 | - | - | - |
Population justification: Waiyaki and Samba (2000) estimated the population to number 1,400 individuals, which is roughly equivalent to 930 mature individuals. Galbusera et al. (2000) estimated the following subpopulation sizes: Mbololo 1,059, Ngangao 250, and Chawia 38, which totals 1,347 individuals, and c.800 mature individuals. Plot-based Capture-Mark-Recapture models by L. Cousseau (as reported by L. Lens in litt. 2019) on data collected between 2000-2010, and the comparisons of annual survival rates during sub-periods between 2000-2010 with those calculated for 1997-2000, suggest the following rates of decline occurred in each subpopulation between 2000-2010: Mbololo (73%), Ngangao (36%), Chawia (41%). The subpopulation sizes in 2010 may therefore have been more like: Mbololo 289, Ngangao 159, and Chawia 23, which would equate to c.280 mature individuals (L. Lens in litt. 2019).
However, the initial figures by Galbusera et al. (2000) were produced via extrapolation. Hence, these figures assume that densities are constant throughout the whole fragment, which is unlikely due to edge effects and that even in dense homogenous forest, density varies significantly. Additionally, using the CMR models to assess absolute population estimates relies on delicate assumptions. Therefore, there is significant uncertainty around the true population size. To account for this, the population estimate is placed in the band 250-999 mature individuals.
Trend justification: Based on the figures from Galbusera et al. (2000) data from the Capture-Mark-Recapture models (L. Lens in litt. 2019), the subpopulations may have reduced from 1,059-289 (Mbololo), 250-159 (Ngangao) and 38-23 (Chawia). Overall, this equates to an overall population decline of 63.4% over three generations. Hence, the population decline is inferred to fall in the band 60-70% over three generations.
| Country/Territory | Occurrence status | Presence | Resident | Breeding | Non-breeding | Passage |
|---|---|---|---|---|---|---|
| Kenya | N | Extant | Yes |
| Country/Territory | IBA Name |
|---|---|
| Kenya | Taita Hills Forests |
| Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
|---|---|---|---|
| Forest | Subtropical/Tropical Moist Montane | major | resident |
| Altitude | 1200 - 2000 m | Occasional altitudinal limits |
| Threat (level 1) | Threat (level 2) | Impact and Stresses | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Agriculture & aquaculture | Annual & perennial non-timber crops - Small-holder farming | Timing | Scope | Severity | Impact | ||||
| Ongoing | Whole (>90%) | Rapid Declines | High Impact: 8 | ||||||
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| Agriculture & aquaculture | Wood & pulp plantations - Scale Unknown/Unrecorded | Timing | Scope | Severity | Impact | ||||
| Ongoing | Whole (>90%) | Rapid Declines | High Impact: 8 | ||||||
|
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| Climate change & severe weather | Habitat shifting & alteration | Timing | Scope | Severity | Impact | ||||
| Future | Whole (>90%) | Unknown | Unknown | ||||||
|
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| Invasive and other problematic species, genes & diseases | Problematic native species/diseases - Unspecified species | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
|
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| Natural system modifications | Fire & fire suppression - Increase in fire frequency/intensity | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Causing/Could cause fluctuations | Medium Impact: 6 | ||||||
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Recommended citation
BirdLife International (2022) Species factsheet: Turdus helleri. Downloaded from
http://www.birdlife.org on 23/05/2022.
Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from
http://www.birdlife.org on 23/05/2022.
