Common name: little tern
Scientific name: Sternula albifrons
Conservation status: This species is listed as Endangered in Queensland (Nature Conservation Act 1992) and is ranked as a high priority under the Department of Environment and Heritage Protection Back on Track species prioritisation framework.
This is the smallest tern in the Australasian region, but is very similar in size, shape and plumage to the fairy tern, Sternula nereis. Its length is 20-28 cm and its wingspan is 45-55 cm. The tail is moderately long and forked, and is slightly shorter than the wing-tips when the bird is at rest. It has a distinctive breeding plumage with black crown and nape and narrow black wedge from eye to bill. Its white forehead extends back over the eye as a narrow eyebrow, and its bill and legs are yellow. Its bill usually has a black tip. The sexes are indistinguishable. Non-breeding birds have a black bill and legs, with a greatly receded black crown.
Habitat and distribution
The little tern is mainly found in coastal environments, including beaches, sheltered inlets, estuaries, lakes, bays and harbours, especially where exposed sandbanks or sand spits occur. It is sometimes found on offshore continental islands or coral cays. Breeding habitat includes sand spits or islets in sheltered coastal environments such as estuaries and inlets, and also sandy ocean beaches, with nests occasionally built in sand dunes. It may also occasionally nest on coral cays.
Its distribution includes all continents except Antarctica. In Australia, it occurs in all coastal areas except the south-west and southern parts of Western Australia, the western half of South Australia and western shores of Tasmania. It is scarce in south-eastern Australia in winter, apparently because Asian birds depart to breed and many of the Australian little tern move to breed along the north coast of Australia.
Life history and behaviour
The little tern usually feeds in small groups, although it often roosts in large flocks on beaches or sand spits with other terns. It is active and noisy; its usual flight call is an excited, high-pitched 'kweek'. Its alarm call is an urgent 'tee-eep, tee-eep, tee-eep'. The little tern flies with deep, rapid wingbeats and hovers rapidly with wings held in a steep 'V' before it plunges into the water when feeding. Breeding colonies are surprisingly unobtrusive and easily overlooked.
The little tern breeds from May to July in the Gulf of Carpentaria, and mostly from September to January along the east coast of Australia. This species lays their eggs in a shallow depression scraped into the sand. Laying does not all occur at the same time, even within individual breeding colonies. Clutch size is one to three eggs and the incubation period is 17-25 days. Chicks are mobile very soon after hatching and leave the nest almost at once. The fledging period (hatching to maturity) is 17-19 days.
Threats known to affect little terns include both natural and human related factors. As little terns nest near the high tide line, occasionally their nests are inundated by king tides. Nests can also be flooded by freshwater run-off following very heavy rain events (depending on the area where the nests are located). Little tern nests may fail as a result of strong wind which can blow loose sand and cover either eggs or small chicks. Other factors affecting little tern reproduction include predation of eggs and chicks. Natural predators include silver gulls, gull-billed terns and torresian crows. Introduced predators known to have an impact on terns include red foxes, wild dogs, feral cats and black rats.
The recreational activities of people in coastal areas can affect little tern breeding success. These activities include driving on beaches, trail bike riding or walking through colonies. These activities can disturb the terns or crush eggs and chicks. Loss of suitable nesting habitat occurs because of coastal development. Little terns are potentially susceptible to pesticides and contamination of estuaries by oil spills and heavy metals.
- Many major breeding sites in Queensland still need to be identified or verified.
- Feral animals, including cats and foxes, need to be controlled at known sites. If you own a dog, avoid walking your dog at sites that are important breeding sites for the little tern.
- Education (including signage) at known sites is essential so that visitors are made aware of the impacts of their activities. Drivers of vehicles on beaches are requested to stay clear of nesting areas. If you own a four-wheel drive, reconsider your need to drive on the beach.
- Local bird groups can become involved in protecting or maintaining important sites and monitoring bird numbers.
- Important sites that are indentified need to be protected from intense development pressures.
Curtis LK, Dennis AJ, McDonald KR, Kyne PM and Debus SJS 2012. Queensland’s Threatened Animals, CSIRO Publishing, Victoria, Australia.
Department of Sustainability, Environment, Water, Population and Communities. 2012. Sternula albifrons Little tern: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra.
Garnett ST, Szabo JK and Duntson G 2011. The action plan for Australian birds 2010. CSIRO Publishing, Collingwood, Victoria.