Data Zone
Taxonomic note
Chlidonias albostriatus (del Hoyo and Collar 2014) was previously placed in the genus Sterna as S. albostriata.
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.
Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.
| Critically Endangered | Endangered | Vulnerable |
|---|---|---|
| - | A2bce+3bce+4bce; C2a(ii) | A2bce+3bce+4bce; C2a(i,ii) |
| Year | Category | Criteria |
|---|---|---|
| 2022 | Endangered | A2bce+3bce+4bce; C2a(ii) |
| 2016 | Endangered | A2bce+3bce+4bce |
| 2012 | Endangered | A2bce+3bce+4bce |
| 2010 | Endangered | A2b,c,e; A3b,c,e; A4b,c,e |
| 2008 | Endangered | A2b,c,e; A3b,c,e; A4b,c,e |
| 2007 | Endangered | |
| 2004 | Endangered | |
| 2000 | Endangered | |
| 1996 | Vulnerable | |
| 1994 | Vulnerable | |
| 1988 | Threatened |
| Migratory status | full migrant | Forest dependency | does not normally occur in forest |
| Land mass type | Average mass | 95 g |
| Estimate | Data quality | |
|---|---|---|
| Extent of Occurrence breeding/resident (km2) | 167,000 | medium |
| Extent of Occurrence non-breeding (km2) | 166,000 | medium |
| Number of locations | - | |
| Severely Fragmented | - |
| Value | Data quality | Derivation | Year of estimate | |
|---|---|---|---|---|
| No. of mature individuals | 1000-5000 | medium | estimated | 2020 |
| Population trend | decreasing | medium | estimated | - |
| Decline (3 years/1 generation past) | - | - | - | |
| Decline (5 years/1 generation past) | - | - | - | |
| Decline (10 years/1 generation past) | - | - | - | |
| Decline (10 years/3 generation future) | 50-70 | - | - | - |
| Decline (10 years/3 generation past and future) | 50-70 | - | - | - |
| Number of subpopulations | 1 | - | - | - |
| Percentage in largest subpopulation | 100 | - | - | - |
| Generation length (yrs) | 8.6 | - | - | - |
Population justification: Previously the population has been estimated at 7,000-10,000 individuals (R. Keedwell in litt. 2006), roughly equivalent to 4,600-6,700 mature individuals. Similarly, based on index counts of rivers, the population was estimated at c.10,000 mature individuals in 2011 (O'Donnell and Hoare 2011). However, data based on genetic samples and evidence of steep ongoing declines (thought to be equivalent to 50-70% within three generations) suggest that the population is less than 10,000 mature individuals at present. Between 2013 and 2015, the effective number of breeders was estimated at around 700 (381-4,229) based on 17 microsatellite loci of 104 chicks (Schlesselmann and Robertson 2020). The effective population size is estimated at 3,216 (1,827-10,611) based on 422 chick and adult samples (Schlesselmann and Robertson 2020). In 2020, the New Zealand Department Conservation estimated there to be 1,000-5,000 mature individuals overall (Robertson et al. 2021).
Trend justification:
Breeding populations on braided rivers in the South Island, New Zealand, are assumed to be in decline as their habitat comes under increasing pressure from exotic pests, hydroelectric power development and water abstraction. A meta-analysis of the trends of the breeding population from 1962 to 2008 (O’Donnell and Hoare 2011) showed that rivers on which declines have occurred are characterised by having relatively low flows. At such rates, populations on low-flow rivers (51.4% of Black-fronted Terns counted on the oldest counts) would decline by a further c. 90% within 25 years. Even if populations on larger rivers were stable, it is predicted that the total population would decline by c.50% over the next 25 years. Although there has not been an updated trend analysis, annual reports continue to show that nest survival is poor across many different river systems such as Aparima, Waitaki, Rangitata, Rakaia, Ashley and Hurunui, with relatively high survival at the Tasman and Clarence rivers due to conservation management (A. Schlesselmann in litt. 2022). Given that most unmanaged river systems have poor nesting success and that the managed population only represents 5-10% of the global population, steep declines are thought to be ongoing and Robertson et al. (2021) estimate an ongoing rate of 50-70% within three generations.| Country/Territory | Presence | Origin | Resident | Breeding | Non-breeding | Passage |
|---|---|---|---|---|---|---|
| New Zealand | extant | native | yes |
| Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
|---|---|---|---|
| Marine Coastal/Supratidal | Sea Cliffs and Rocky Offshore Islands | suitable | non-breeding |
| Marine Intertidal | Shingle and/or Pebble Shoreline and/or Beaches | suitable | non-breeding |
| Marine Neritic | Estuaries | major | non-breeding |
| Wetlands (inland) | Permanent Freshwater Lakes (over 8ha) | suitable | breeding |
| Wetlands (inland) | Permanent Rivers/Streams/Creeks (includes waterfalls) | major | breeding |
| Altitude | 0 - 1860 m | Occasional altitudinal limits |
| Threat (level 1) | Threat (level 2) | Impact and Stresses | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Human intrusions & disturbance | Recreational activities | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Canis familiaris | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
|
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Cytisus scoparius | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
|
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Erinaceus europaeus | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Rapid Declines | Medium Impact: 7 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Felis catus | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Very Rapid Declines | High Impact: 8 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Gymnorhina tibicen | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
|
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Mustela erminea | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Rapid Declines | Medium Impact: 7 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Mustela furo | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Rapid Declines | Medium Impact: 7 | ||||||
|
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Named species | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Slow, Significant Declines | Low Impact: 5 | ||||||
|
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Named species | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Negligible declines | Low Impact: 4 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Rattus norvegicus | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Very Rapid Declines | High Impact: 8 | ||||||
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| Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Rattus rattus | 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 - Trichosurus vulpecula | Timing | Scope | Severity | Impact | ||||
| Ongoing | Unknown | Unknown | Unknown | ||||||
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| Invasive and other problematic species, genes & diseases | Problematic native species/diseases - Circus approximans | 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 | Problematic native species/diseases - Haematopus finschi | Timing | Scope | Severity | Impact | ||||
| Ongoing | Unknown | Unknown | Unknown | ||||||
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| Invasive and other problematic species, genes & diseases | Problematic native species/diseases - Larus dominicanus | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
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| Natural system modifications | Dams & water management/use - Abstraction of surface water (agricultural use) | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Slow, Significant Declines | Low Impact: 5 | ||||||
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| Natural system modifications | Dams & water management/use - Dams (size unknown) | Timing | Scope | Severity | Impact | ||||
| Future | Minority (<50%) | Very Rapid Declines | Low Impact: 5 | ||||||
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Recommended citation
BirdLife International (2023) Species factsheet: Chlidonias albostriatus. Downloaded from
http://datazone.birdlife.org/species/factsheet/black-fronted-tern-chlidonias-albostriatus on 07/06/2023.
Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from
http://datazone.birdlife.org on 07/06/2023.
