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 |
|---|---|---|
| - | B2ab(ii,iii,v) | B1ab(ii,iii,v)+2ab(ii,iii,v) |
| Year | Category | Criteria |
|---|---|---|
| 2019 | Endangered | B2ab(ii,iii,v) |
| 2016 | Endangered | B1ab(i,iii,v) |
| 2012 | Endangered | B1ab(i,iii,v) |
| 2009 | Endangered | B1a+b(iii,v) |
| 2008 | Least Concern | |
| 2004 | Least Concern | |
| 2000 | Lower Risk/Least Concern | |
| 1994 | Lower Risk/Least Concern | |
| 1988 | Lower Risk/Least Concern |
| Migratory status | not a migrant | Forest dependency | does not normally occur in forest |
| Land-mass type | Average mass | - |
| Estimate | Data quality | |
|---|---|---|
| Extent of Occurrence (breeding/resident) | 7,600 km2 | medium |
| Area of Occupancy (breeding/resident) | 440 km2 | |
| Number of locations | 2-5 | - |
| Severely fragmented? | no | - |
| Estimate | Data quality | Derivation | Year of estimate | |
|---|---|---|---|---|
| Population size | 2500-9999 mature individuals | poor | suspected | 2012 |
| Population trend | decreasing | poor | suspected | 1996-2009 |
| Generation length | 4.4 years | - | - | - |
Population justification:
Pierce et al. (2007) recorded densities of up to 50 birds/km2 on Kiritimati and pairs reportedly occupy a territory of 1.8-2.3 ha, which coarsely equates to 100 mature individuals/km2. Combined, the islands of Kiritimati and Teraini have a land area of 336 km2, suggesting they could support a maximum of c.16,000-30,000 mature individuals. However, the species is absent from considerable areas of these two islands, likely due to unsuitable habitat, and occurs at lower densities, especially where invasive predators are present. Consequently, a global population of 2,500-9,999 mature individuals is suspected, though this may prove to be an overestimate and further surveys are required. This is equivalent to 3,750-14,999 individuals in total, rounded here to 3,500-15,000 individuals. Observations at Kiritimati in 2013 suggested that densities were highly variable, ranging from 0.1 to 1.1 birds per hectare and averaging 0.47 individuals per hectare of surveyed habitat (VanderWerf 2014, Pierce et al. 2015).
Trend justification: Population trends have not been empirically assessed, but the species has been extirpated from one island (Tabueran) in the 1970s, and threats within its extant range include introduced predators and habitat degradation driven by a variety of processes. However, on Kiritimati, monitoring has been ongoing since 2007, but no declines have been detected (R. Pierce in litt. 2016). The species is precautionarily assessed as having a small ongoing decline. Should the species be found not to be declining overall, it would warrant downlisting to a lower threat category.
| Country/Territory | Presence | Origin | Resident | Breeding visitor | Non-breeding visitor | Passage migrant |
|---|---|---|---|---|---|---|
| Kiribati | extant | native | yes |
| Country/Territory | IBA Name |
|---|---|
| Kiribati | Kiritimati (Christmas Island) |
| Kiribati | Teraina (Washington Island) |
| Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
|---|---|---|---|
| Shrubland | Subtropical/Tropical Moist | major | resident |
| Altitude | 0 - 20 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 | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
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| Biological resource use | Hunting & trapping terrestrial animals - Persecution/control | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
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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 | Invasive non-native/alien species/diseases - Felis catus | Timing | Scope | Severity | Impact | ||||
| Ongoing | Whole (>90%) | Slow, Significant Declines | Medium Impact: 7 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Pluchea indica | Timing | Scope | Severity | Impact | ||||
| Ongoing | Whole (>90%) | Negligible declines | Medium Impact: 6 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Rattus rattus | Timing | Scope | Severity | Impact | ||||
| Ongoing | Whole (>90%) | Slow, Significant Declines | Medium Impact: 7 | ||||||
|
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| Natural system modifications | Fire & fire suppression - Increase in fire frequency/intensity | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
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| Residential & commercial development | Housing & urban areas | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Slow, Significant Declines | Low Impact: 5 | ||||||
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| Purpose | Scale |
|---|---|
| Pets/display animals, horticulture | international |
Recommended citation
BirdLife International (2024) Species factsheet: Kiritimati Reed-warbler Acrocephalus aequinoctialis. Downloaded from
https://datazone.birdlife.org/species/factsheet/kiritimati-reed-warbler-acrocephalus-aequinoctialis 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.