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Sterna albostriata
– Endangered
Taxonomy
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Kingdom:
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ANIMALIA
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Phylum:
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CHORDATA
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Class:
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AVES
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Order:
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CHARADRIIFORMES
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Family:
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LARIDAE
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Scientific Name:
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Sterna albostriata
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Species Authority:
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(Gray, 1845)
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Synonym/s:
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Chlidonias albostriatus (Gray, 1845)
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Common Name/s:
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BLACK-FRONTED TERN (Eng)
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Assessment Information
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Red List Category & Criteria:
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EN A2abce+3bce ver 3.1 (2001)
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Year Assessed:
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2007
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Assessor/s:
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Birdlife International
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Evaluator/s:
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Benstead, P., Bird, J., Butchart, S., McClellan, R. & Stattersfield, A. (BirdLife International Red List Authority)
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Justification:
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This tern has a small population that has shown recent very rapid population reductions at some wintering and breeding sites, which are predicted to continue in the future due to ongoing threats. It is therefore considered Endangered.
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History:
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| 1988 | - | Threatened (Collar and Andrew 1988) |
| 1994 | - | Vulnerable (Collar, Crosby and Stattersfield 1994) |
| 2000 | - | Endangered (BirdLife International 2000) |
| 2004 | - | Endangered (BirdLife International 2004) |
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Geographic Range
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Range Description:
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Sterna albostriata breeds in the South Island, New Zealand. It is found along the eastern riverbeds from Marlborough to Southland, and on the upper Motueka and Buller Rivers in southern Nelson3. Birds disperse to the coastline and estuaries in winter, mostly from Stewart Island to the southern North Island, feeding at sea within 10 km of the coast3,6. The most recent estimate puts the total population at 7,000 to 10,000 individuals10. All populations of this species that have been studied have been in decline7. Numbers recorded in the Bay of Plenty during winters in the 1980s ranged between 25 and 45. Since 2000, counts at the same site have varied between 10 and 16 (M. Szabo in litt. 2006). Similarly on the breeding grounds, numbers on the Ashburton River declined from over 750 birds in 1981 to less than 200 by 1990 (Maloney 1999, O'Donnell 1992, Taylor 2000). A total of 55 individuals was recorded in the lower 18 km of the Ashley River in 1980 (Wildlife Service surveys) with just 26 and 28 in the same area in 2005-2006 (J. Dowding in litt. 2006). These and other observations indicate that the species may be in widespread decline4,5,6,9.
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Countries:
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Native:
New Zealand
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Population
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Population Trend:
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Habitat and Ecology
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Habitat and Ecology:
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It breeds on riverbeds, creating simple scrapes in the shingle. It usually lays two eggs. Young fledge at c.30 days old. It feeds on freshwater invertebrates, small fish, earthworms and other terrestrial invertebrates (on pastureland) and, when at sea, mainly crustaceans3.
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System:
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Terrestrial; Freshwater; Marine
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Threats
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Threats:
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Introduced mustelids Mustela spp., feral cats, brown rat Rattus norvegicus, hedgehogs, brush-tailed possum Trichosurus vulpecula, dogs, and Australian Magpie Gymnorhina tibicen prey on this species6,8. Major breeding failures have been recently reported at colonies as a result of predation7,8. Cattle and sheep can disturb breeding colonies. Recreational activities, presently increasing rapidly, can cause breeding failure and disturbance at wintering sites. Further hydroelectric developments are a major threat; notably a proposed project on the Wairau River where 12% of the population currently nest9. Invasion of introduced weed species and tree planting along riverbeds reduces available habitat6. Confinement of rivers to a single channel reduces the availability of nesting "islands"1.
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Conservation Actions
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Conservation Actions:
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Conservation measures underway:
Several studies have been completed covering aspects of the species's biology and ecology. Habitat restoration and fauna monitoring is carried out by Project River Recovery in a number of major riverbed habitats in the McKenzie basin, covering part of the range2,6.
Conservation measures proposed:
Census and map all breeding colonies. Census winter flocks. Monitor accessible colonies annually. Examine all proposals for hydro-dams or irrigation projects to identify impacts on the species. Establish nest protection if predation is identified as significantly affecting breeding success. Spray weeds on rivers if required6. Commence trial of establishing islands/rafts in lagoons and tarns1.
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