Biodiversity

Species Profile and Threats Database


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EPBC Act Listing Status Listed marine
Listed migratory - CAMBA, JAMBA, ROKAMBA
Adopted/Made Recovery Plans
Federal Register of
    Legislative Instruments
List of Migratory Species (13/07/2000) (Commonwealth of Australia, 2000b) [Legislative Instrument].
 
Declaration under section 248 of the Environment Protection and Biodiversity Conservation Act 1999 - List of Marine Species (Commonwealth of Australia, 2000c) [Legislative Instrument].
 
Environment Protection and Biodiversity Conservation Act 1999 - Listed Migratory Species - Approval of an International Agreement (Commonwealth of Australia, 2007h) [Legislative Instrument].
 
State Listing Status
SA: Listed as Rare (National Parks and Wildlife Act 1972 (South Australia): Rare species: June 2011)
Scientific name Sterna hirundo [795]
Family Laridae:Charadriiformes:Aves:Chordata:Animalia
Species author Linnaeus, 1758
Infraspecies author  
Reference  
Distribution map Species Distribution Map not available for this taxon.
Illustrations Google Images

Scientific Name: Sterna hirundo (Linnaeus, 1758)

Common Name: Common Tern.

Other English names: Asiatic Common Tern, Black-billed Common Tern, European Common Tern, Western Common Tern, Sea-swallow (AOU 1998; Avibase 2008e; Gill & Wright 2006, 2008; Gochfeld & Burger 1996; Higgins & Davies 1996; Nisbet 2002).

The Common Tern is a conventionally accepted species, with three or four subspecies currently recognised (Christidis & Boles 2008; Gochfeld & Burger 1996; Higgins & Davies 1996).

Common Terns are medium-sized and slender sea-terns (total length 31–37 cm; adult weight 110–145 g) with long narrow wings and a long, deeply forked tail (with the tips of the tail-streamers falling level with the folded wing-tips).

Breeding
Breeding adults are distinctive, with largely light-grey upperparts, marked with a black cap, contrastingly white rump and uppertail-coverts, grey-black sides of tail and slightly darker grey primaries. The underparts are largely pale grey with a contrastingly white vent and undertail-coverts, and a white underwing with thin black stripe on the outermost primary and a dusky black trailing edge. In Sterna hirundo longipennis, the bill is black or black with a dull reddish-black or reddish base, the eyes dark brown, and the legs and feet are dusky red to reddish brown; in the subspecies Sterna hirundo hirundo the bill and legs are wholly red.

Non-breeding
In non-breeding plumages, adults differ from those in breeding plumage by: white forehead and lores that merge to dirty white and black-streaked crown and black half-cap on the rear crown, nape and ear-coverts, and with a large black patch in front of the eye; pale grey rump merging into white uppertail-coverts; and a conspicuous black cubital bar and a dusky secondary bar on the upperwing and a dusky wedge on the outer upperwing. The underparts are also white. The bill is black, occasionally with a red tinge at the base, and the legs usually black or black faintly tinged with red.

Juveniles
Juveniles are like non-breeding adults but with a buff wash to the forehead and lores, and a dark-brown to blackish crown, nape and ear-coverts; the mantle, back, scapulars, tertials, and innerwing-coverts are pale grey with varyingly strong dark-brown crescents or spots; and the hindneck-collar and underparts are white. The upperwing is largely light grey with a conspicuous black cubital bar, dusky grey patch at the carpal joint, dusky grey secondary bar and white trailing edge not reaching the tip of wing. The bill is dark brown or blackish with an orange or pink base, soon becoming wholly black, and the legs and feet pinkish or orange-brown (Cramp 1985; Gochfeld & Burger 1996; Higgins & Davies 1996; Nisbet 2002; Olsen & Larsson 1995).

Common Terns are typically gregarious, roosting and foraging in small flocks, but can be seen singly and in large groups, sometimes in hundreds, or even several thousands, at preferred sites. They sometimes forage in dense flocks over abundant prey, such as schools of fish. The species migrates in flocks. They often associate with other terns, such as White-winged Black Terns (Chlidonias leucopterus), Little Terns (Sternula albifrons) and White-fronted Terns (Sterna striata) (Cramp 1985; J. Dening 2008, pers. comm.; Gochfeld & Burger 1996; Higgins & Davies 1996; Milledge 1977; Mullarney 1988b; Nisbet 2002; Olsen & Larsson 1995).

The species is a non-breeding migrant to Australia, where it is widespread and common on the eastern coast south to eastern Victoria, and common on parts of the northern coast, mainly east of Darwin. The subspecies occurring in Australia is predominantly Sterna hirundo longipennis, though nominate S.h. hirundo has also been recorded, apparently in small numbers (Barrett et al. 2003; Blakers et al. 1984; Brandwood 2000; Chatto 2006; Higgins & Davies 1996; Johnstone & Storr 1996). Forms treated as a subspecies (S.h. minussenis) by some authors are considered to be intergrades between S.h. longipennis and nominate S.h. hirundo by Cramp (1985) and Higgins and Davies (1998). These may also be represented in Australia.

In Australia, Common Terns are mainly found along the eastern coast, where they are widespread and common from south-eastern Queensland to eastern Victoria (extending south-west to Port Albert), though less often recorded south of Port Hacking in NSW. Elsewhere on the eastern coast, they occur in the eastern Torres Strait and more sparsely from there south to Rockhampton. In northern Australia, there are only scattered records in the Kimberley Division of Western Australia, but the species has recently been found to be one of the most abundant species recorded in ground surveys of waterbirds of the Top End of the Northern Territory, including Groote Eylandt, and is also widespread in the Gulf of Carpentaria and along western Cape York Peninsula. In southern Australia, other than the south-east, the species is only rarely recorded in south-western Victoria and south-eastern South Australia (though recorded increasingly frequently in the latter in recent decades). In Western Australia, the species is rarely recorded south of approximately 30° S, with only scattered records north of there to the Kimberley Division. The species is a vagrant to Tasmania (Barrett et al. 2003; Blakers et al. 1984; Chan & Dening 2007; Chan et al. 2008; Chatto 2006; de Rebeira & de Rebeira undated; Higgins & Davies 1996; Jaensch et al. 1988; Johnstone & Storr 1998; Serventy et al. 1971). Elsewhere in Australian territory, the species is a rare visitor to Lord Howe and Cocos-Keeling Islands (Gibson-Hill 1949b, 1950c; Higgins & Davies 1996; McAllan et al. 2004).

There is no estimate of the extent of occurrence of the Common Tern in Australia. The species has a large worldwide range, with an estimated global extent of occurrence of 10 000 000 km² (BirdLife International 2007o). The source of this estimate is not known, and there are no available data to indicate past declines or future changes.

The estimated area of occupancy of the Common Tern in Australia is 37 600 km².

Globally, the species is widespread, breeding throughout Eurasia and North America and wintering widely in the southern hemisphere.

There are no known captive populations of this species and the species has not been reintroduced into the wild in Australia or elsewhere.

The species has a widespread and largely continuous breeding distribution through much of Eurasia and in North America, an extensive non-breeding range along the coasts of most continents and many islands, and overall the distribution does not appear to be fragmented. However some breeding populations are, or appear to be, isolated and are threatened. For example, the Gulf of Mexico breeding population is geographically disjunct and critically endangered, numbering just 12 pairs; and the breeding colony on Bermuda was destroyed by a hurricane in 2003, declining from 20 pairs, to only 12 birds, probably all females (Wetlands International 2006).

This species breeds in North America and Eurasia. In North America, breeding is recorded from Alberta and Montana east to southern Quebec, Newfoundland and the north-eastern USA, with scattered breeding on USA coasts south to North Carolina and in the Gulf of Mexico, as well as in Bermuda, the Greater and Lesser Antilles and islands off Venezuela.

In Eurasia, breeding is recorded throughout temperate Europe and Asia from the Azores, Canary Islands, British Isles and Norway east to the Gulf of Anadyr, Kurile Islands, Sakhalin, North Korea and north-eastern China, mainly south of 62–65° N but extending north of the Arctic Circle in northern Norway and eastern Siberia. The southern limit of the breeding range in Eurasia-Africa is somewhat fragmented, but includes locations in Mauritania, Guinea-Bissau, Tunisia, Israel, Kuwait, Iran, Afghanistan, northern India and Tibet. Breeding has also been recorded in Nigeria.

During the non-breeding period, the species is almost cosmopolitan. Terns winter in North and South America, on the Pacific coast from southern California and Baja California, south through Central America to southern Peru, and on the Atlantic coast from Newfoundland and Gulf of St Lawrence, south to Florida, the Gulf of Mexico and Caribbean islands, to Colombia and Venezuela and the entire eastern coast of South America to southern Argentina, ranging to islands in the South Atlantic. They also occupy the entire coasts of Africa and Europe except for the coast of the Barents Sea. In southern Asia, they occur from the Red Sea and Arabian Peninsula, east to the western and south-eastern coast of India, north to the Bay of Bengal and inland along the Ganges River. In south-eastern and eastern Asia, Common Terns are widespread from eastern Siberia and the Kamchatka Peninsula, south through Japan and eastern China and the coast of the Gulf of Thailand to the southern Malay Peninsula, Indonesia, the Solomon Islands, New Guinea and Australia.

Vagrants are recorded widely, including in New Zealand and on the Hawaiian Islands (Ali & Ripley 1969; AOU 1998; Coates 1985; Coates & Bishop 1997; Cramp 1985; Gochfeld & Burger 1996; Higgins & Davies 1996; Nisbet 2002; Urban et al. 1986; White & Bruce 1986).

The species has a large global population, estimated to be 1 100 000–4 500 000 individuals (BirdLife International 2007o; Wetlands International 2006); Gochfeld and Burger (1996) give a world population of at least 250 000, and possibly as many as 500 000 pairs. Global populations appear to be largely stable, though different populations appear to show different trends, some showing long-term (30 year) decreases but stable or increasing populations over the last 10 years, whereas others are stable over the long term but decreasing or stable over the last 10 years (Wetlands International 2006). The species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (declining more than 30% in 10 years or three generations). Globally, the species is listed as Least Concern (BirdLife International 2007o).

The proportion of the global population of Common Terns in Australia is not known (Higgins & Davies 1996).

The distribution of Common Terns in Australia is well known through past and ongoing bird atlas projects of Birds Australia and the activities of bird groups throughout Australia. Common Terns, along with other migrant and resident species of terns, were the target of a three-year study of terns on the Caloundra sandbanks in south-eastern Queensland (Chan & Dening 2007); and of a 16-month survey at the Noosa sandbanks 50 km north of Caloundra (Chan et al. 2008), with counts continuing to the present (J. Dening 2008, pers. comm.). The species has also been widely recorded during surveys of waterbirds of the Top End and associated seas of the Northern Territory (Chatto 2006). However, Common Terns frequent marine habitats more than terrestrial wetlands (Chatto 2006) and thus significant populations are not likely to be picked up in terrestrial wetland surveys. Further, because Common Terns are diurnal as well as marine foragers, daytime surveys fail to count populations accurately and crepuscular surveys need to be conducted (J. Dening 2008, pers. comm.). It is possible that detailed surveys of the Gulf of Carpentaria coast and waters during the austral spring-summer may find other significant sites where large numbers of non-breeding Common Terns congregate.

The species has a large global population, estimated to be 1 100 000–4 500 000 individuals (BirdLife International 2007o; Wetlands International 2006).

Three or four subspecies of Common Tern are usually recognised, with populations of Sterna hirundo hirundo and S.h. longipennis intergrading over a wide area in central Asia, and which are treated as a separate subspecies (S.h. minussenis) by some authors (AOU 1998; Gochfeld & Burger 1996; Higgins & Davies 1996; Nisbet 2002). Overall, the species has a widespread and largely continuous breeding distribution through much of Eurasia and in North America and the distribution does not appear to be fragmented.

Global populations of Common Terns appear to be largely stable, though different populations appear to show different trends. For example, the breeding population of the Atlantic coast of North America (approximately 90 000 pairs, 270 000 individuals) shows a long-term (30 year) increasing trend but populations were possibly decreasing or stable over the last 10 years. In contrast, the population of the Great Lakes of North America (approximately 9000–10 000 pairs, 27 000–30 000 individuals) shows a long-term decreasing trend but appeared to be stable over the last 10 years (Nisbet 2002; Wetlands International 2006). The species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (declining more than 30% in 10 years or three generations) (BirdLife International 2007o).

In Australia, numbers of non-breeding birds in NSW are thought to be increasing, with greater numbers in some areas where they were previously scarce or absent (Morris et al. 1990). For example, in Sydney Harbour National Park, Common Terns were seldom reported before 1970 but more recent counts are typically of up to 60 birds (Higgins & Davies 1996; Morris 1986).

The species does not appear to undergo large natural fluctuations in numbers, though natural events, such as cyclones, can devastate colonies or local populations (Nisbet 2002; Wetlands International 2006). In Australia, Common Terns showed no significant regional variation and no significant difference in reporting rate in surveys for the Atlas of Australian Birds for 1998 to 2001 compared with 1977 to 1981 (Barrett et al. 2002). However, counts at individual sites vary annually, for example at Caloundra, in south-eastern Queensland, the median count (with maximum annual counts in parentheses) over each of three years were 1039 (23 863), 709 (38 054) and 9509 (34 262) birds (Chan & Dening 2007).

The lifespan of the Common Tern is 18–23 years. In a sample of eastern USA colonies, most birds bred at three years old, with < 10% breeding at two years old and < 20% first breeding at four years old. Median age of breeders is approximately nine to ten years old. Estimates of average annual adult survival range from 0.88 to 0.925 (Nisbet 2002).

Common Terns do not breed in Australia but this country appears to be an important wintering destination. Greatest concentrations appear to occur in south-eastern Queensland (Chan & Dening 2007) and in northern Australia, where surveys can be difficult in the wet season (Barrett et al. 2003; Chatto 2006). At Caloundra, in south-eastern Queensland, the median and maximum counts, respectively, over each of three years were 1039 and 23 863, 709 and 38 054, and 9509 and 34 262 birds (Chan & Dening 2007). Common Terns were the most abundant bird visiting the Caloundra sandbanks, with a count of > 38 000 birds in one summer and counts of > 10 000 on 25 other occasions. At this site, Common Terns comprised an average 35% of all birds found on the sandbanks, approximately 60% of all migrant terns, and on several occasions, formed > 80% of all birds occupying the sandbanks. It is possible that the Caloundra sandbanks hold the highest concentration of non-breeding Common Terns of subspecies S.h. longipennis at any one site within Australia and one of the largest in the world (Chan & Dening 2007). Also in south-eastern Queensland, surveys of sandbanks at Noosa, 50 km north of Caloundra, obtained counts of up to 35 000 birds (subspecies S.h. longipennis) but at higher densities than recorded at Caloundra, which makes the Noosa sandbanks an internationally important area for migratory terns. The sandbanks at Noosa and Caloundra probably represent a contiguous wintering ground on the Sunshine Coast for migrant terns, with individual birds using both areas (Chan et al. 2008). In surveys of the Northern Territory, Chatto (2006) made 108 ground or boat records of Common Terns, totalling > 20 700 birds (with additional records from aerial surveys) and considers it likely that the species may well be one of the most abundant birds of the Top End if all territorial waters were included in the survey area. However, because most foraging by Common Terns was at sea and many birds arrived at roost after dark, only a tiny proportion of the population was ever surveyed. Although not seen to form large pre-migration flocks (like White-winged Black Terns), large groups of Common Terns were seen roosting on the Perron Islands, on Mooroongga Island (3000 birds, October 1994), on the coast just north of Numbulwar (approximately 2500 Terns, September 1994), and there were two records, involving a total of 5500 Common Terns, on the intertidal sandflats and mudflats on the south-western coast of Groote Eylandt (February 1996). Further, about 1000 Terns were seen foraging at sea to the north-east of Croker Island in December 2004 (Chatto 2006). Elsewhere in Australia, large numbers are occasionally recorded at some localities, for example records of up to or exceeding 1000 birds at Nambucca Heads, Long Reef and Botany Bay, NSW (Higgins & Davies 1996).


Hybridisation with Roseate (Sterna dougallii), Forster's Terns (S. forsteri ) and Little Terns has been reported. Reports of possible hybridization with Arctic Terns (Sterna paradisaea) are unconfirmed (Hays 1975; Higgins & Davies 1996; McCarthy 2006; Mullarney 1988a; Nisbet 2002).

Given the widespread distribution around Australia the species is recorded in many areas designated as reserves, though none appear to be specifically managed for this species. However, large and internationally significant numbers occur annually on the Caloundra and Noosa sandbanks in south-eastern Queensland. It is possible that Caloundra sandbanks hold the highest concentration of non-breeding Common Terns of subspecies Sterna hirundo longipennis at any one site in Australia and one of the largest in the world, and subsequent surveys of the Noosa sandbanks to the north of Caloundra found equivalent numbers to Caloundra but at greater densities (Chan & Dening 2007; Chan et al. 2008; Dening 2003). The sandbanks at Noosa and Caloundra probably represent a contiguous wintering ground on the Sunshine Coast for migrant terns (Chan et al. 2008). The Caloundra sandbanks lie within the Moreton Bay Marine Park, which is also a designated Ramsar site, but the area should be regarded as an Area of International Importance based on criteria contained in the Ramsar Convention (Chan & Dening 2007; Dening 2003). However, the Noosa sandbanks, which are also an internationally important area for migratory terns, are not protected within reserves. The Noosa estuary should be included as an Area of International Importance based on the populations of Common Tern alone (Chan et al. 2008).

Common Terns are marine, pelagic and coastal. In Australia, they are recorded in all marine zones, but are commonly observed in near-coastal waters, both on ocean beaches, platforms and headlands and in sheltered waters, such as bays, harbours and estuaries with muddy, sandy or rocky shores. However, off Wollongong, NSW, Common Terns were recorded in all marine zones but generally recorded in offshore and pelagic waters, 11–55 km from shore. Occasionally they are recorded in coastal and near-coastal wetlands, either saline or freshwater, including lagoons, rivers, lakes, swamps and saltworks. Sometimes they occur in mangroves or saltmarsh and, in bad weather, in coastal sand-dunes or coastal embayments (Brandis et al. 1992; Chatto 2006; Higgins & Davies 1996; Hitchcock 1965; Morris 1989; Morris et al. 1981, 1990; Wood 1991).

Common Terns forage in marine environments, often close to the shore, including sheltered embayments and in the surf-zone, but also well out to sea. They also forage in near-coastal terrestrial wetlands, including estuaries, rivers and swamps (Cramp 1985; Gochfeld & Burger 1996; Higgins & Davies 1996; Hitchcock 1965; Milledge 1977; Nisbet 2002; Serventy et al. 1971). There has been one record of foraging behind a trawler in the Gulf of Carpentaria (Blaber & Milton 1994). Common Terns roost on unvegetated, intertidal sandy ocean beaches, sandy islands, shores of estuaries or lagoons, and sandbars, as well as on rocky shores, rock platforms or rocks protruding above the surface of the water. In poor weather, they have been recorded sheltering in coastal sand-dunes or coastal embayments. They are often recorded perched on wooden structures protruding from the water, including piers, wharves, groynes and posts and on moored boats. They often roost in large flocks, for example, up to 38 000 birds observed roosting on Noosa sandbanks (Chan & Dening 2007; Chan et al. 2008; Chatto 2006; Cramp 1985; Higgins & Davies 1996; Hitchcock 1965; Morris 1989; Morris et al. 1990).

Common Terns nest on the ground in the open, usually on bare substrates, occasionally near vegetation or in it, or on a floating mat of vegetation. They usually nest on islands, either marine or in lakes, only sometimes on mainland beaches or promontories or salt or freshwater marshes. Common Terns often nest in sites washed over by winter storms or floods. In North America, most nesting areas are found < 5 m above high-water mark and < 100 m from the edge of the water. In Europe, and occasionally elsewhere, the species nests on rivers (Cramp 1985; Gochfeld & Burger 1996; Nisbet 2002; Ramos & del Nevo 1995).

The species is not known to use refuge habitats.

Common Terns are not known to rely on any threatened ecological community in Australia, nor are they specifically associated with any threatened species though they potentially share habitat with such species. The Caloundra and Noosa sandbanks, in south-eastern Queensland, are major sites for the species (with counts of more than 38 000 birds at Caloundra and estimated maximum counts of 30 000–35 000 birds roosting at night at Noosa). The Caloundra sandbanks lie within the Moreton Bay Marine Park, which is a Ramsar site (No. 41), but the site is adjacent to the Caloundra Central Business District (CBD) and subject to increasing levels of human recreational and tourism activity (Chan & Dening 2007; Chan et al. 2008; Dening 2003). Both the Caloundra and Noosa sandbanks should be regarded as Areas of International Importance based on criteria contained in the Ramsar Convention (Chan & Dening 2007; Chan et al. 2008).

In a sample of eastern USA colonies, most birds breed at three years old, with < 10% breeding at two years old and < 20% first breeding at four years old. In Germany, some 75% of surviving birds first returned to their natal colony at two years old, and approximately 20% at three years old, with the rest at four to five years old (Nisbet 2002).


Common Terns do not breed in Australia (Higgins & Davies 1996). Within their breeding range, the species nests in the boreal spring-summer, from May to September. Common Terns usually breed in colonies, of a few pairs to 1800 pairs, but sometimes nest solitarily. They often nest close to other species of tern. Most birds breed annually, and raise one brood each season. The clutch-size is one to three eggs, usually two to three, but varies between colonies. Breeding success is usually high, but annual colony rates range from 0 to > 2.5 fledged chicks/pair, with consistently higher productivity in larger colonies. Reproductive performance improves with age, and productivity continues to increase until death. In Massachusetts, USA, the median breeding lifetime is approximately seven years (Cramp 1985; Nisbet 2002).

Common Terns are fairly opportunistic, with a diet predominantly of small fish (greater than or equal to 15 cm in length), though also often taking crustaceans or insects, and occasionally squid. The species rarely take other invertebrates. When breeding, the species almost always eats live prey but is known to take dead fish and fish offal in non-breeding areas (Cramp 1985; Gochfeld & Burger 1996; Higgins & Davies 1996; Nisbet 2002). In the Northern Territory, when weather conditions are good, Common Terns forage well out to sea and will rest on the sea during the day, returning to land at night to roost. When weather conditions are poor or they are able to find food close to islands, they come to land to rest during the day between bouts of foraging (Chatto 2006).

Little information on diet from Australia exists, but the species is recorded eating fish (including Clupeidae and Engraulididae) and insects (including Orthoptera, Coleoptera, Lepidoptera and Hymenoptera) (Barker & Vestjens 1989; Higgins & Davies 1996; Hitchcock 1965; Milledge 1977).
Common Terns forage mainly by surface or shallow plunge-diving, typically from 2–3 m above the surface of the water. Common Terns also forage by contact-dipping and aerial dipping, taking prey from on or just below the surface. They have also been seen sallying for insects and gleaning on the ground, and will steal food from other terns, especially when food is scarce (Cramp 1985; Gochfeld & Burger 1996; Higgins & Davies 1996; Milledge 1977). They often forage in tight formations.

This species is strongly migratory, breeding in the northern hemisphere in the boreal spring-summer and migrating south to wintering areas in the Northern and Southern Hemispheres (Higgins & Davies 1996).

Subspecies Sterna hirundo longipennis is the common form recorded in Australia, with a non-breeding range that extends from the Malay Peninsula and Philippines through Indonesia and New Guinea to Australia, with stragglers occurring in New Zealand and the Cocos-Keeling Islands. The non-breeding range may also extend to southern Asia. These individuals leave northern regions of the breeding range in late August to early September, and depart southern regions somewhat later, in late September. Birds migrate south along the Asian coastline. Common Terns arrive north-western and northern Australia from late August, with some moving south along the western coast. The Common Tern is also recorded in Darwin as early as August-September.

In eastern Australia, they appear to move south along the coast. Common Terns are recorded in Queensland from September, and usually arrive in NSW from late September to October. In Victoria, reporting rates increase during September-October. Birds leave Australia between March and May, though some remain during the austral winter. In Australia, reporting rates are 1.2% during summer and 0.2% during winter (Blakers et al. 1984; Chan & Dening 2007; Chatto 1996; Coates & Bishop 1997; Cramp 1985; Gochfeld & Burger 1996; Higgins & Davies 1996; Nisbet 2002; Serventy et al. 1971).

In surveys of the Top End of the Northern Territory, Common Terns were recorded in all months except January (when they were also likely to have been present but not surveyed), but showed a large annual increase in numbers from September and a decrease in March. Not all birds leave the region each year (Chatto 2006). At Caloundra, in south-eastern Queensland, Terns begin to arrive October and most leave by mid-April, with greatest numbers generally from late December to early April (Chan & Dening 2007; Dening 2003). Their distribution in some areas of Australia may relate to abundance of food, and some occurrences are associated with severe weather conditions (Blakers et al. 1984; Crawford 1972; Higgins & Davies 1996).

The other subspecies recorded in Australia is S.h. hirundo, which occurs in small numbers in south-western Australia from September to April, and as an accidental in Victoria, with records in October. Palaearctic and Oriental populations move to non-breeding areas in Africa, Portugal and Spain, the southern Caspian Sea and Persian Gulf, the Indian Subcontinent and possibly the Malay Peninsula. European populations leave their breeding grounds from late July to October, and western Siberian populations mainly leave by late August or early September. Nearctic (the area covering most of North America, including Greenland and the highlands of Mexico) populations of S.h. hirundo leave their breeding grounds during August-December, and move to non-breeding areas in the Caribbean, Central America, South America and islands of the South Atlantic (Blakers et al. 1984; Gochfeld & Burger 1996; Higgins & Davies 1996; Nisbet 2002; Serventy et al. 1971; Urban et al. 1986). It has been suggested that Australian records of this subspecies are of birds blown east by prevailing westerly winds at latitudes of southern Africa (Higgins & Davies 1996).

Banding recoveries show that some individuals move long distances. A bird banded as a pullus (a chick) in Sweden, was recovered six months later in south-western Western Australia (Serventy & Whittell 1976); a bird banded in Ireland was recovered in Victoria over nine years and five months after banding (Anon. 1969; Rogers 1969c); and a nestling banded in Finland was recovered in Victoria over five months after banding, 15 192 km from the banding site (Anon. 1997). Of birds banded in Australia, individuals banded in Victoria have been recovered in eastern Siberia; and an adult banded in Victoria was recovered in the Philippines over nine months after banding (Anon. 1999e). Some recaptures of S. h. longipennis in Victoria indicate at least some fidelity to non-breeding areas, although there are few recoveries of birds elsewhere in subsequent summers (Higgins & Davies 1996).
Common Terns do not breed in Australia and do not appear to defend territories in Australia, or elsewhere in their non-breeding range, and there is no information on individual home-range in non-breeding season. When breeding, they typically range up to 10 km from colonies, less often to around 30 km (Nisbet 2002).

In Australia, the species is similar to and often confused with Little Terns, and both Arctic and White-fronted Terns.

Common Terns are in Australia primarily during the austral spring-summer, with only small numbers present in the austral winter (Chan & Dening 2007; Chatto 2006; Higgins & Davies 1996). Most surveys of the species are ground counts conducted from the shoreline or counts from boats due to access issues (Chan & Dening 2007; Chatto 2006). The species has been counted during aerial surveys of wetlands of the Northern Territory, and surveyed at sea by boat (Chatto 2006). However, the largely marine foraging of this species in northern Australia, and elsewhere, means numbers are not adequately recorded during surveys of terrestrial wetlands (Chatto 2006).

In eastern Australia, the Caloundra and Noosa sandbanks, in south-eastern Queensland, are major sites for the species (with counts of 38 000 birds). Both sites are adjacent to large and rapidly growing human population centres and subject to increasing levels of human recreational and tourism activity (such as boating, diving, fishing, bait gathering, and use of jet-skis, and similar motorised personal watercraft), some of which are known to affect the behaviour of birds and all of which potentially threaten the use of the area by terns (and other species). In particular, the explosion in the popularity of kite-surfing poses a threat that may become severe. Further, populations of Common Terns at these sites are greatest in summer, which is also when human activity in the surrounding waters peaks (Chan & Dening 2007; Chan et al. 2008; Dening 2003; J. Dening 2008, pers. comm.). At the Noosa sandbanks, most human disturbance occurred during high tide and on sandbanks closest to the mainland, with people and dogs the most common human-related disturbances. Human disturbance was greatest on weekends and public holidays and on some sandbanks during such times, birds were completely excluded by the sheer volume of people present. The mean flight-initiation distance for Common Terns on the Noosa sandbanks was 29.6 m (range 20–36 m, n = 4 events) (Chan et al. 2008).

Populations of this species were greatly reduced in the nineteenth century, mainly as a result of collecting of eggs for food, hunting and killing for the millinery trade, as well as loss and degradation of habitat associated with human development.

In North America, pesticide-induced reproductive failure probably contributed to population declines during the late 1950s and 1960s. Many populations have since recovered with protection.

Declines in some colonies are currently occurring, associated with a range of factors, such as: human predation (for example, in western Africa); ongoing habitat degradation, increased predation of eggs and chicks and displacement from breeding colonies by gulls (Larus species); predation by introduced rats; and pesticides and other environmental pollutants, including oiling. Human disturbance (such as boating, jet-skis, 4WDs) can prevent occupation of sites, promote desertion or cause losses of eggs and chicks (through chilling, overheating, increased predation), though there is little evidence that such disturbance causes substantial adverse effects on breeding birds in North America. Nevertheless, it is recommended that breeding colonies be buffered from human disturbance by a critical distance of 200 m, which is the distance at which breeding birds can be approached without eliciting escape or anti-predator behaviour (e.g. Blokpoel et al. 1997; Burger 1998; Cramp 1985; Erwin 1989; Gochfeld & Burger 1996; Nisbet 2000, 2002; Nocera & Kress 1996).

Nesting on the ground makes the species vulnerable to predators. Breeding success was found to be higher when nesting on man-made sites (such as navigational aids or man-made islands), compared to natural sites, probably owing to lower levels of predation (Karwowski et al. 1995). Breeding birds readily habituate to predictable human activity and can become very tolerant of research activities (Nisbet 2000, 2002).

In eastern Australia, the identification of the Caloundra and Noosa sandbanks as a major roosting site for Common Terns, and other migratory and resident terns, has been a significant step towards protection of the sites. Ongoing counts and management at this site are aiming to protect the area for this and other species of tern.

The Caloundra sandbanks lie within the Moreton Bay Marine Park, which is also a designated Ramsar site (No. 41) (Chan & Dening 2007; Dening 2003). At Caloundra, signs have also been placed strategically to inform the public of the importance of the site for terns. The work of Chan and Dening (2007) has also alerted government managers to the importance of the site to migratory terns. They also suggest that additional mitigation measures may need to be considered, one being the introduction of a buffer zone around the sandbanks to keep human traffic away from roosting birds to reduce the effect of disturbance.

At the Noosa sandbanks, Chan and colleagues (2008) suggest that promotion of nature-based tourism focussing on the terns could be a means of protecting them and their roosting habitat with closure of the principal roosting sites at peak times of use by terns. A section of the sandbanks is now closed to the public between October and March and accompanied with signage. Further, Chan and colleagues (2008) indicate that a common management plan needs to be in place for all the sandbanks and estuaries within the Caloundra-Noosa system, and declaration of the entire region as a Ramsar site. Further work is also needed to determine the use of other estuaries by the same birds in the region, including the Maroochy estuary and the Great Sandy Strait.

Other than protection of important areas in conservation reserves and the threat abatement measures at the Caloundra and Noosa sandbanks, as identified above, there are no other mitigation measures currently being implemented in Australia.

Within Australia, the major studies of the species are those by Chan and Dening (2007) and Chan and colleagues (2008) in eastern Australia, and the work of Chatto (2006) in the Northern Territory. Detailed summaries of current knowledge of the species in Australasia are found in Higgins and Davies (1996), and Johnstone and Storr (1998). There have been many overseas studies, much of which is summarized in the major works on the birds of these regions (Ali & Ripley 1969; Cramp 1985; Gochfeld & Burger 1996; Nisbet 2002; Urban et al. 1986). The species has been the subject of two recent monographs, by Hume (1993) and Burger and Gochfeld (1991a), and the papers from a symposium on the biology, status and management of the species in Europe have also been published in Die Vogelwelt (see Becker & Sudmann 1998).

No specific management documents relating to this species are known, though management issues are addressed in detail in Chan and Dening (2007) and Chan and colleagues (2008).

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
Human Intrusions and Disturbance:Human Intrusions and Disturbance:Human induced disturbance due to unspecified activities Sterna hirundo in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006xz) [Internet].
Human Intrusions and Disturbance:Recreational Activities:Recreational use of marine environment Sterna hirundo in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006xz) [Internet].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Predation, competition, habitat degradation and/or spread of pathogens by introduced species Sterna hirundo in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006xz) [Internet].

Ali, S. & S.D. Ripley (1969). Handbook of the Birds of India and Pakistan. Volume 3. Bombay: Oxford Unversity Press.

American Ornithologists Union (AOU) (1998). Check-list of North American Birds. Seventh Edition. Washington, DC: American Ornitholoigsts Union.

Anon (1969). Recovery round-up. Australian Bird Bander. 7:40-44.

Anon (1997). Recovery round-up. Corella. 21:67-68.

Anon (1999e). Recovery round-up. Corella. 23:51-52.

Avibase (2008e). Common Tern (Sterna hirundo). Viewed 2 May 2008. [Online]. Available from: http://www.bsc-eoc.org/avibase/.

Barker, R.D. & W.J.M. Vestjens (1989). The Food of Australian Birds. 1 Non-Passerines. Lyneham, ACT: CSIRO.

Barrett, G., A. Silcocks, R. Cunningham & R. Poulter (2002). Comparison of Atlas 1 (1977-1981) and Atlas 2 (1998-2001): Supplementary Report No. 1. Melbourne: Birds Australia, report for Natural Heritage Trust.

Barrett, G., A. Silcocks, S. Barry, R. Cunningham & R. Poulter (2003). The New Atlas of Australian Birds. Melbourne, Victoria: Birds Australia.

Becker, P.H. & S.R. Sudmann (1998). Quo vadis Sterna hirundo? Schlußfolgerungen für den Schutz der Flussseeschwalbe. [Quo vadis Sterna hirundo? Implications for the conservation of the Common Tern in Germany.]. Vogelwelt. 119:293-304.

BirdLife International (2007o). Species factsheet: Sterna hirundo. BirdLife International, Cambridge, UK. Viewed 2 May 2008]. [Online]. Available from: http://www.birdlife.org.

Blaber, S.J.M. & D.A. Milton (1994). Distribution of seabirds at sea in the Gulf of Carpentaria, Australia. Australian Journal of Marine and Freshwater Research. 45:445--454.

Blakers, M., S.J.J.F. Davies & P.N. Reilly (1984). The Atlas of Australian Birds. Melbourne, Victoria: Melbourne University Press.

Blokpoel, H., G.D. Tessier & R.A. Andress (1997). Successful restoration of the Ice Island Common Tern colony requires on-going control of Ring-billed Gulls. Colonial Waterbirds. 20:98--101.

Brandis, C.C.P., C.J. Chafer, & L.E. Smith (1992). Seabirds recorded off Wollongong, New South Wales 1984-1990. Australian Bird Watcher. 14:165-179.

Brandwood, K. (2000). Rare birds in New South Wales in 1996 & 1997. Seventh report of the NSW Ornithological Records Appraisal Committee. Australian Birds. 32(1):65-73.

Burger, J. (1998). Effects of motorboats and personal watercraft on flight behaviour over a colony of Common Terns. Condor. 100:528-534.

Burger, J. & M. Gochfeld (1991a). The Common Tern: Its Breeding Biology and Social Behavior. New York: Columbia University Press.

Chan K., Dening, J. & Malinen, L.. (2008). Can tern migrants coexist with urban development and estuarine recreational activities?. In: Wetlands: Ecology, Conservation and Restoration. Hauppauge, N.Y: Nova Science Publishers.

Chan, K. & J. Dening (2007). Use of sandbanks by terns in Queensland, Australia: a priority for conservation in a popular recreational waterway. Biodiversity and Conservation. 16(2):447-464.

Chatto, R. (2006). The Distribution and Status of Waterbirds Around the Coast and Coastal Wetlands of the Northern Territory. Palmerston, NT: Parks and Wildlife Commission of the Northern Territory.

Christidis, L. & W.E. Boles (2008). Systematics and Taxonomy of Australian Birds. Collingwood, Victoria: CSIRO Publishing.

Coates, B.J. (1985). The Birds of Papua New Guinea. Volume 1. Alderley, Queensland: Dove Publications.

Coates, B.J. & K.D. Bishop (1997). A Guide to the Birds of Wallacea Sulawesi, The Moluccas and Lesser Sunda Islands, Indonesia. Alderley, Queensland: Dove Publications.

Cramp, S. (1985). Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palearctic. Volume 4. Oxford: Oxford University Press.

Crawford, D.N. (1972). Birds of Darwin area, with some records from other parts of Northern Territory. Emu. 72:131-48.

de Rebeira, A. & de Rebeira, P. (undated). Birds of Eyre. An Annotated List.

Dening, J. (2003). Major tern site on Qld coast. The Tattler. 36:6.

Dening, J. (2008). Personal communication.

Erwin, R.M. (1989). Responses to human intruders by birds nesting in colonies: experimental results and management guidelines. Colonial Waterbirds. 12:104-108.

Gibson-Hill, C.A. (1949b). The birds of the Cocos-Keeling Islands (Indian Ocean). Ibis. 91:221-243.

Gibson-Hill, C.A. (1950c). Notes on the birds of the Cocos-Keeling Islands. Bulletin of the Raffles Museum. 22:212-270.

Gill, F. & M. Wright (2006). Birds of the World: Recommended English Names. Princeton, NJ: Princeton University Press.

Gill, F. & M. Wright (2008). IOC English Names of Birds Project (version 1.1). Viewed 21 April 2008. [Online]. Available from: http://www.worldbirdnames.org/n-shorebirds.html.

Gochfeld, M. & J. Burger (1996). Family Sternidae (Terns). In: del Hoyo, J A. Elliott & J. Sargatal, eds. Handbook of the Birds of the World. Volume 3: Hoatzin to Auks. Page(s) 624-667. Barcelona: Lynx Edicions.

Hays, H. (1975). Probable Common × Roseate Tern hybrids. Auk. 92(2):219-234.

Higgins, P.J. & S.J.J.F. Davies, eds (1996). Handbook of Australian, New Zealand and Antarctic Birds. Volume Three - Snipe to Pigeons. Melbourne, Victoria: Oxford University Press.

Hitchcock, W.B. (1965). Geography and seasonal movements of the Common Tern in Australia. Emu. 64:157-171.

Hume, R. (1993). The Common Tern. London: Hamlyn.

Jaensch, R.P., R.M. Vervest & M.J. Hewish (1988). Waterbirds in nature reserves of south-western Australia 1981-1985: reserve accounts. RAOU Report Series. 30.

Johnstone, R.E. & G.M. Storr (1998). Handbook of Western Australian Birds. Vol. 1: Non-passerines (Emu to Dollarbird). Perth, Western Australia: West Australian Museum.

Karwowski, K., J.E. Gates & L.H. Harper (1995). Common Terns nesting on navigational aids and natural islands in the St. Lawrence River, New York. Wilson Bulletin. 107:423-436.

McAllan, I.A.W., B.R. Curtis, I. Hutton & R.M. Cooper (2004). The birds of the Lord Howe Island Group: a review of records. Australian Field Ornithology. 21:1-82.

McCarthy, E.M. (2006). Handbook of Avian Hybrids of the World. New York: Oxford University Press.

Milledge, D. (1977). One year's observations of seabirds in continental shelf waters off Sydney, N.S.W. Corella. 1:1-12.

Morris, A.K. (1986). The birds of Sydney Harbour National Park, New South Wales. Australian Birds. 20:65--81.

Morris, A.K. (1989). The birds of Botany Bay National Park. Australian Birds. 23:7-21.

Morris, A.K., A.R. McGill & G. Holmes (1981). Handlist of Birds in New South Wales. Sydney: NSW Field Ornithologists Club.

Morris, A.K., V. Tyler, M. Tyler, H. Mannes & J. Dalby (1990). A waterbird survey of the Parramatta River wetlands, Sydney, New South Wales. Australian Birds. 23:44-64.

Mullarney, K. (1988a). Identification of a Roseate x Common Tern hybrid. Dutch Birding. 10(3):133-135.

Mullarney, K. (1988b). Identification of adult Roseate Tern. Dutch Birding. 10:135-137.

Nisbet, I.C.T. (2000). Disturbance, habituation, and management of waterbird colonies. Waterbirds. 23:313-322.

Nisbet, I.C.T. (2002). Common Tern (Sterna hirundo). No. 618. Viewed 2 May 2008. Poole, A., ed. The Birds of North America Online. [Online]. Ithaca: Cornell Lab of Ornithology. Available from: http://bna.birds.cornell.edu/bna/species/618.

Nocera, J.J. & S.W. Kress (1996). Nocturnal predation on Common Terns by Great Black-backed Gulls. Colonial Waterbirds. 19:277-279.

Olsen, K.M., & H. Larsson (1995). Terns of Europe and North America. London: Christopher Helm.

Ramos, J.A. & A.J. del Nevo (1995). Nest-site selection by Roseate Terns and Common Terns in the Azores. Auk. 112:580-589.

Rogers, A.E.F. (1969c). Common Tern recovery in Australia. Australian Bird Bander. 7:36.

Serventy, D.L., V.N. Serventy & J. Warham (1971). The Handbook of Australian Seabirds. Sydney, NSW: A.H. & A.W. Reed.

Urban, E.K., C.H. Fry & S. Keith (1986). The Birds of Africa. Volume 2. London: Academic Press.

Wetlands International (2006). Waterbird Population Estimates. Fourth Edition. Wageningen, The Netherlands: Wetlands International.

White, C.M.N. & M.D. Bruce (1986). The birds of Wallacea. B.O.U. Check-list. 7.

Wood, K.A. (1991). Gulls and Terns (Laridae) off Wollongong, New South Wales: Seasonal abundance, scavenging behaviour and depth zonation. Corella. 15:93-102.

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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 hirundo in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Fri, 18 Apr 2014 22:09:33 +1000.