In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.
|EPBC Act Listing Status||
Listed as Vulnerable
This taxon may be listed under the EPBC Act at the species level, see Sterna vittata .
|Recovery Plan Decision||
Recovery Plan required, this species had a recovery plan in force at the time the legislation provided for the Minister to decide whether or not to have a recovery plan (19/2/2007).
|Adopted/Made Recovery Plans||
National Recovery Plan for Ten Species of Seabirds 2005-2010 (Department of the Environment and Heritage (DEH), 2005f) [Recovery Plan].
|Policy Statements and Guidelines||
Survey Guidelines for Australia's Threatened Birds. EPBC Act survey guidelines 6.2 (Department of the Environment, Water, Heritage and the Arts (DEWHA), 2010l) [Admin Guideline].
Federal Register of
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument].
|Non-statutory Listing Status||
|Scientific name||Sterna vittata vittata |
|Species author||Gmelin, 1789|
This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.
The current conservation status of the Antarctic Tern (Indian Ocean), Sterna vittata vittata, under Australian Government legislation, is as follows:
National: Listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).
Listed as Marine, under Sterna vittata, under the EPBC Act.
Scientific name: Sterna vittata vittata
Common name: Antarctic Tern (Indian Ocean)
Other names: Wreathed Tern
The Antarctic Tern (Indian Ocean) is a conventionally accepted subspecies of the Antarctic Tern. However, the subspecific arrangement of the Antarctic Tern is based on morphological data from only some of the known breeding populations, with the remainder assigned a tentative subspecific status on the basis of their geographical proximity to studied populations (Higgins & Davies 1996; Murphy 1938).
The Antarctic Tern (Indian Ocean) is about 32 to 34 cm in length with a mass between 115 and 188 g. Adults are predominantly white and grey with a red bill and a partially black head. The colour of the bill and extent of black on the head varies seasonally. In the breeding season, the bill is bright red and a black cap forms over the head. In the non-breeding season, the bill fades to dark red and the black cap recedes to some streaking across the crown and a band that extends from the eyes to the nape. Juveniles can be distinguished from the adults by their buff wash and coarse buff and black markings (Higgins & Davies 1996).
The only location within the Australian territory, from which the Antarctic Tern (Indian Ocean) is known to breed, is Heard Island in the south-west Indian Ocean (Downes et al. 1959; Higgins & Davies 1996; Woehler 1991, 2006). The distribution of the subspecies at sea is poorly known. During the breeding season, adults are believed to forage in shallow waters close to shore. During the non-breeding season, the distribution is believed to extend from the waters around Heard Island into international waters (Brooke et al. 1988; Tree & Klages 2004; Watson 1975; Woehler 2006; Woehler et al. 1990). Based on records of unknown subspecies collected from Metricup in south-west Western Australia and South Casuarina Island in South Australia, it might occasionally reach the coastal waters of mainland Australia (Higgins & Davies 1996). Adults that breed on Heard Island are known to winter in southern Africa (Woehler 2006). A migratory route between Heard Island and southern Africa has therefore been inferred.
The extent of occurrence of the Australian breeding colonies of the Antarctic Tern (Indian Ocean) is estimated to be 10 km2. This estimate is based on the distribution of known colonies of the Antarctic Tern (Indian Ocean) and the extent of potential colony sites (i.e. ice-free areas) available on Heard Island (Woehler 2006). There is no conclusive evidence of any change in the extent of occurrence of the Australian breeding colonies. Some sites reportedly occupied by breeding pairs in the 1950s were found to be vacant during surveys in the 1980s, 1990s and 2000s, although, it is believed that not all nesting sites are used in each breeding season (Woehler 2006).
The area of occupancy of the Australian breeding colonies of the Antarctic Tern (Indian Ocean) is estimated to be 2 km2 (Garnett & Crowley 2000). There is no conclusive evidence of any change in the area of occupancy of the Australian breeding colonies.
Outside of Australian jurisdiction, the Antarctic Tern (Indian Ocean) breeds on Bouvetøya, the Prince Edward Islands, Iles Crozet and Iles Kerguelen (Higgins & Davies 1996; Murphy 1938). Its distribution at sea is poorly known, but probably extends from the waters around Heard Island, west across the southern Indian Ocean to the waters around Bouvetøya in the southern Atlantic Ocean, south to the coastal waters of Antarctica and north to the coastal waters of southern Africa and, possibly, mainland Australia (Brooke et al. 1988; Tree & Klages 2004; Watson 1975; Woehler et al. 1990).
The global breeding population of the Antarctic Tern (Indian Ocean) is estimated at about 2265 pairs (Crawford & Cooper 2003; Tree & Klages 2004). The overall trend in global population size is unknown. The breeding populations on Iles Kerguelen (approximately 2000 pairs) and Iles Crozet (approximately 100 pairs) appear to have changed little since the 1980s (Jouventin et al. 1984; Tree & Klages 2004; Weimerskirch et al. 1989), but the breeding population on the Prince Edwards Islands has evidently declined from 10-30 pairs in 1975 (Berruti & Harris 1976) to less than 15 pairs in the early 2000s (Crawford & Cooper 2003; Crawford et al. 2003). It is not possible to determine the trend in the breeding population on Heard Island (approximately 100-200 pairs) (Woehler 2006) due to a lack of data. At the species level, the Antarctic Tern is classified as being of 'Least Concern' at the global population level (BirdLife International 2004). Approximately 5-10% of the global breeding population of the Antarctic Tern (Indian Ocean) nests on Heard Island (Crawford & Cooper 2003; Tree & Klages 2004; Woehler 2006).
Antarctic Tern (Indian Ocean) colonies on Heard Island were surveyed opportunistically in the late 1940s and early 1950s (Downes et al. 1959), 1983 (Vining 1983) and 1987-1988 (Copley 1989). All active and historical breeding sites were surveyed and mapped in 2000-2001 and 2003-2004 (Woehler 2006).
Approximately 100-200 pairs of the Antarctic Tern (Indian Ocean) nest on Heard Island (Woehler 2006) and there is insufficient data to determine trends. Downes and colleagues (Downes et al. 1959) reported a seasonal maximum of about 50 birds in the 'Four Bays' area of the island in the 1950s. Forty-eight nests were present in the Stephenson Glacier moraine in 1983 (Vining 1983) and 13 nests were present in this same area in 1987-1988 (Copley et al. 1989).
Heard Island and the nearby McDonald Islands are together designated as a World Heritage Area. Additionally, the waters surrounding Heard Island and the McDonald Islands are managed for conservation purposes through the Heard Island and McDonald Islands Marine Reserve.
During the breeding season, the Antarctic Tern (Indian Ocean) forages close to shore, and mostly within the kelp-zone that extends up to 200 m from shore, in the shallow waters of coves, bays, inlets, harbours and estuaries. It typically feeds close to, or in, the surf zone, and often amongst heavy surf, diving from heights of 1-4 metres above the water's surface to capture prey. It occasionally forages much farther from shore, particularly during the non-breeding season, when it migrates over pelagic waters between breeding and wintering sites. It rarely feeds on land, although it was observed, on a single occasion, to pick food items from wet sand exposed by receding waves (Woehler 2007 pers. comm.).
The Antarctic Tern (Indian Ocean) nests on rocky terrain that is typically located less than 1 km from the coast. Nests can be situated amongst boulders at the bases of cliffs, on rocky ridges, spits and peninsulas, headlands, rock stacks, rocky islets, pinnacles, glacial moraines, raised lava platforms, rock fields in close proximity to fresh water, and boulder-strewn beaches. It rarely nests at sites other than these, although breeding has also been recorded on coarse shingle beaches and, at Heard Island, on outwash flats below glacial snouts. Nests can be situated amongst low, sparse vegetation such as mosses and grasses (Poa spp.) (Higgins & Davies 1996; Woehler 2002 pers. comm.).
The Antarctic Tern (Indian Ocean) usually roosts on rocky surfaces, especially on ledges and in cavities of steep coastal cliffs and stacks, or on rocky ridges. It roosts less regularly on wet sand on sheltered beaches in coves and estuaries (Higgins & Davies 1996; Woehler 2002 pers. comm.). It typically roosts close to its nesting sites during the breeding season (Woehler & Auman 2001).
No information is available on age of sexual maturity, life expectancy or natural mortality in the Heard Island population. In other species in the subfamily Sterninae, individuals can begin to breed at two, three or four years of age (Higgins & Davies 1996).
During the breeding season, pairs of the Antarctic Tern (Indian Ocean) defend a restricted area around the nest (Downes et al. 1959). Pairs can nest solitarily or colonially, with nests separated by as little as 3 m (Sagar 1991; Woehler 2007 pers. comm.). On Heard Island, the Antarctic Tern (Indian Ocean) breeds in small colonies of 3-15 pairs, with nests separated from one another by distances of 3-10 metres. The dispersion of nests in these colonies may reflect a lack of suitable nesting sites rather than a preferred spatial arrangement (Woehler 2007 pers. comm.).
Egg laying occurs during late December to February, with young being present until April, or rarely until July (Downes et al. 1959; Higgins & Davies 1996). They have a clutch size usually of one, sometimes two, and rarely three eggs are recorded. The breeding success is thought to be low, based on limited data (Downes et al. 1959; Higgins & Davies 1996).
Breeding success is influenced by weather conditions, with increased wind speed reported to lower the growth rate of chicks and reduce the ability of parents to feed their young. It is possible that birds may initiate breeding when conditions are favourable (Sagar 1991), although such calm conditions are rare on the subantarctic islands on which the subspecies breeds (Woehler 2007 pers. comm.).
The Antarctic Tern (Indian Ocean) is carnivorous, feeding mainly on fish and crustaceans, and rarely on molluscs, algae and insects (Higgins & Davies 1996).
When foraging, the Antarctic Tern (Indian Ocean) patrols back and forth at a height of 3-8 m above the water's surface, behind and within the surf zone, and sometimes within 5 m of the shore. It forages in flocks of more than 100 birds at Heard Island (Woehler 2002 pers. comm., 2007 pers. comm.). On sighting its prey, the Antarctic Tern (Indian Ocean) may hover and then plunge, or make a low dipping flight to the surface, to snatch prey. Strong winds and rough seas inhibit its ability to forage, as quantified by reductions in the frequency of foraging attempts and the rates of prey capture (Higgins & Davies 1996; Sagar 1991).
It has been suggested that the Antarctic Tern (Indian Ocean) migrates from its Subantarctic and Antarctic breeding grounds to over-winter in southern Africa (Higgins & Davies 1996), with recent evidence supporting this claim (Woehler 2002 pers. comm., 2006). Most birds or, on some islands, the entire population depart from breeding islands during the non-breeding season. Adults and fledged young generally leave the breeding grounds between January and May. They depart from Iles Kerguelen by the end of April, from Heard Island by June and from Iles Crozet by July. The return migration to breeding grounds generally occurs from September to October. On Iles Crozet, they generally return during November, and on Heard Island and Iles Kerguelen, during December (Sagar 1991; Higgins & Davies 1996; Woehler 2002 pers. comm., 2006, 2007 pers. comm).
On Marion Island (off the South African coast in the subantarctic Indian Ocean), most birds depart by June, however some birds remain on the island throughout the year (Burger 1978b). Little is known about these birds' movements during the non-breeding period. However, birds banded during the non-breeding season in South Africa, including off Bird Island in Algoa Bay near Port Elizabeth, have been recorded at Iles Kerguelen and Heard Island during the breeding season (Sagar 1991; Higgins & Davies 1996; Woehler 2002 pers. comm., 2006, 2007 pers. comm.).
During the breeding season, pairs of the Antarctic Tern (Indian Ocean) defend a restricted area around the nest (Downes et al. 1959). Pairs can nest solitary or colonially, with nests separated by as little as 3 m (Sagar 1991; Woehler 2007 pers. comm.). On Heard Island, the Antarctic Tern (Indian Ocean) breeds in small colonies of 3-15 pairs, with nests separated from one another by distances of 3-10 metres. The dispersion of nests in these colonies may reflect a lack of suitable nesting sites rather than a preferred spatial arrangement (Woehler 2007 pers. comm.).
The main potential threat to the Antarctic Tern (Indian Ocean) population on Heard Island is the accidental introduction of the Rat (Rattus rattus) (Garnett & Crowley 2000) or other vertebrate predators such as the Cat (Felis catus) (Brooke et al. 1988). Rats are known to raid nests of subspecies Antarctic Tern (New Zealand) on Campbell Island (Sadleir et al. 1986) and are alleged to have caused colonies of subspecies S. v. tristanensis to abandon accessible nest sites on Tristan da Cunha (Elliott 1957). The small size and restricted distribution of the population on Heard Island may also render it vulnerable to catastrophic events such as disease or severe weather events (Garnett & Crowley 2000). Other potential threats include disturbance of breeding pairs by human activity, which can cause adults to abandon eggs or chicks and/or result in opportunistic predation of unguarded eggs or chicks by the Kelp Gull (Larus dominicanus) or skuas (Catharacta spp.) (Woehler 2007 pers. comm.).
The Antarctic Tern (Indian Ocean) is likely to benefit from the following actions:
- Opportunistic monitoring of seabird populations on Heard Island (Garnett & Crowley 2000; Woehler 2006).
- Monitoring the breeding population on Heard Island (as no regular visits are made to Heard Island this will be on an opportunistic basis only) to determine directions and rates of population change (DEH 2005f).
- Identifying any emerging actual threats to the population and developing measures to alleviate these threats (DEH 2005f).
- Instigating research to improve biological and ecological knowledge of the subspecies (DEH 2005f).
- Developing and implementing quarantine measures. For example, quarantine protocols have been established and are outlined in the Heard Island and McDonald Islands Marine Reserve Management Plan (AAD 2005).
- Establishing a 100 m buffer around breeding colonies or lone nests, except where permission is granted for research purposes, to prevent disturbance of breeding pairs (DEH 2005f).
There have not been any major studies on the Antarctic Tern (Indian Ocean) in Australia, although a series of reasonably detailed opportunistic observations were collated by Downes and colleagues (1959) and the results of two targeted surveys were reported by Woehler (2006).
The National recovery plan for ten species of seabirds 2005/2010 includes recommendations for the recovery of the Antarctic Tern (Indian Ocean).
The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.
|Threat Class||Threatening Species||References|
|Climate Change and Severe Weather:Climate Change and Severe Weather:Climate change altering atmosphere/hydrosphere temperatures, rainfall patterns and/or frequency of severe weather events||Sterna vittata vittatain Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006yc) [Internet].|
|Human Intrusions and Disturbance:Human Intrusions and Disturbance:Human induced disturbance due to unspecified activities||Sterna vittata vittatain Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006yc) [Internet].|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or predation||Rattus rattus (Black Rat, Ship Rat)||Sterna vittata vittatain Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006yc) [Internet].|
|Species Stresses:Indirect Species Effects:Low numbers of individuals|
Australian Antarctic Division (AAD) (2005). Heard Island and McDonald Islands Marine Reserve Management Plan. Kingston, Tasmania: Australian Antarctic Division.
Berruti, A. & A. Harris (1976). Breeding schedules of Antarctic and Kerguelen Terns at Marion Island. Notornis. 23:243-245.
BirdLife International (2007). Sterna vittata: 2007 IUCN Red List of Threatened Species. [Online]. www.iucnredlist.org.
Brooke, R.K., J. Cooper, P.A.R. Hockey, P.G. Ryan, J.C. Sinclair, W. Suter & A.J. Tree (1988). Distribution, population size and conservation of the Antarctic Tern Sterna vittata in southern Africa. Cormorant. 16:107-113.
Burger, A.E. (1978b). Notes on Antarctic Terns at Marion Island. Cormorant. 4:30-32.
Copley, P.B. (1989). Summary of bird observations, east Heard Island, 1987-88. Kirkwood, R.J., E.J. Woehler, & H.R. Burton (Eds), eds. Heard Island ANARE Report. Page(s) 10-24. ANARE. Kingston, Tasmania: Australian Antarctic Division.
Crawford, R.J.M. & J. Cooper (2003). Conserving surface-nesting seabirds at the Prince Edward Islands: the roles of research, monitoring and legislation. African Journal of Marine Science. 25:415-426.
Crawford, R.J.M., J. Cooper, B.M. Dyer, M. Greyling, N.T.W. Klages, P.G. Ryan, S. Petersen, L.G. Underhill et al (2003). Populations of surface-nesting seabirds at Marion Island, 1994/95-2002/03. African Journal of Marine Science. 25:427-440.
Department of the Environment and Heritage (DEH) (2005f). National Recovery Plan for Ten Species of Seabirds 2005-2010. [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/seabirds.html.
Department of the Environment, Water, Heritage and the Arts (DEWHA) (2010l). Survey Guidelines for Australia's Threatened Birds. EPBC Act survey guidelines 6.2. [Online]. Canberra, ACT: DEWHA. Available from: http://www.environment.gov.au/epbc/publications/threatened-birds.html.
Downes, M.C., E.H.M. Ealey, A.M. Gwynn & P.S. Young (1959). The Birds of Heard Island. Australian National Antarctic Research Reports (Series B).
Elliott, H.F.I. (1957). A contribution to the ornithology of the Tristan da Cunha group. Ibis. 99:545-586.
Garnett, S.T. & G.M. Crowley (2000). The Action Plan for Australian Birds 2000. [Online]. Canberra, ACT: Environment Australia and Birds Australia. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/action/birds2000/index.html.
Higgins, P.J. & S.J.J.F. Davies, eds. (1996). Handbook of Australian, New Zealand and Antarctic Birds. In: Volume Three - Snipe to Pigeons 3. Melbourne: Cambridge University Press.
Jouventin, P., J.C. Stahl, H. Weimerskirch & J.L. Mougin (1984). The seabirds of the French subantarctic islands and Adelie Land, their status and conservation. Croxall, J.P., P.G.H. Evans & R.W. Schreiber, eds. Status and conservation of the world's seabirds. Page(s) 609-625. Cambridge, U.K.: International Council for Bird Preservation (Techn. Publ. 2).
Murphy, R.C. (1938). Birds collected during the Whitney South Sea Expedition. XXXVII. On pan-Antarctic terns. American Museum Novitates. 977:1-17.
Sagar, P.M. (1991). Aspects of the breeding and feeding of Kerguelen and Antarctic Terns at the Kerguelen Islands. Notornis. 38:191--198.
Tree, A.J. & N.T.W. Klages (2004). Population size, distribution and origins of Antarctic Terns Sterna vittata wintering in South Africa. Marine Ornithology. 32:55-61.
Vining, R., ed. (1983). Heard Island Expedition 1983. Sydney: Garvan Institute of Medical Research.
Watson, G.E. (1975). Birds of the Antarctic and Sub-Antarctic. Washington, D.C.: American Geophysical Union.
Weimerskirch, H., R. Zotier & P. Jouventin (1989). The avifauna of the Kerguelen Islands. Emu. 89:15--29.
Woehler, E. & H. Auman (2001). Colour-flagged Antarctic Terns at Heard Island. Australian Bird Study Association Newsletter. 62:9.
Woehler, E.J (1991). The status and conservation of seabirds of Heard Island and the McDonald Islands. In: Croxall, J.P, ed. Seabird Status and Conservation. ICBP Technical Publication No. 11. Page(s) 263-277. ICBP. ICBP, Cambridge, UK.
Woehler, E.J. (2002). Personal communication.
Woehler, E.J. (2006). Status and conservation of the seabirds of Heard Island and the McDonald Islands. In: Green, K., & E.J. Woehler, eds. Heard Island, Southern Ocean Sentinel. Page(s) 128-165.
Woehler, E.J. (2007). Personal communication. School of Zoology, University of Tasmania. September 2007.
Woehler, E.J., C.L. Hodges & D.J. Watt (1990). An Atlas of the Pelagic Distribution and Abundance of Seabirds in the Southern Indian Ocean, 1981 to 1990. Tasmania: Australian National Antarctic Research Expeditions.
This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.
Citation: Department of the Environment (2014). Sterna vittata vittata in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Fri, 25 Apr 2014 14:40:56 +1000.