134Wildlife Conservation Plan for Seabirds

134 Wildlife Conservation Plan for Seabirds

Little Tern (Sternula albifrons)

TABLE Species information for the Little Tern (Sternula albifrons)

The Little Tern (Sternula albifrons) is the smallest tern in the Australian region. The species is very similar in size and shape to Fairy Tern (S. nereis) and much smaller and slimmer than commic terns and Black-naped Tern (Sterna sumatrana). Adults in breeding plumage can be easily identified by diagnostic patterns of head and bill. This species breeds through much of Europe, scattered along the coast and inland in parts of Africa, in much of western, central and the east and south of Asia, and in parts of Australasia. Migratory individuals expand the range to include most of the coast of Africa, the Arabian Peninsula, the western coast of India and most of the waters of south-east Asia and Australasia.

Little Terns favour sheltered coastal environments, including lagoons, estuaries, river mouths and deltas, lakes, bays, harbours and inlets, especially those with exposed sandbanks or sandpits. The species breeds on barren or sparsely vegetated beaches, islands and spits of sand, shingle, shell fragments, pebbles, rocks or coral fragments on seashores or in estuaries, saltmarshes, saltpans, offshore coral reefs, rivers, lakes and reservoirs (Flint et al. 1984, de Silva 1991, del Hoyo et al. 1996). It may also nest on dry mudflats in grassy areas but shows a preference for islets surrounded by saline or freshwater, where small fish can be caught without the need for extensive foraging flights (de Silva 1991, del Hoyo et al. 1996, Snow and Perrins 1998).

The nest is a bare scrape positioned on the ground in less than 15 per cent vegetation cover on beaches of sand, pebbles, shingle, shell fragments, coral fragments or rock above the high tide-line and often only a few metres away from shallow clear water (Flint et al. 1984, Richards 1990, del Hoyo et al. 1996, Snow and Perrins 1998). In more marshy habitats (e.g. coastal saltmarshes), the species may build a nest of shells or vegetation (del Hoyo et al. 1996). The species nests in small loose colonies, with neighbouring nests usually placed more than 2 m apart (del Hoyo et al. 1996). Its diet consists predominantly of small fish and crustaceans 3-6 cm long as well as insects, annelid worms and molluscs (del Hoyo et al. 1996).

The global population is estimated to number 190,000–410,000 individuals (Delany and Scott 2006). The overall population trend is decreasing, although some populations have unknown or increasing trends (Delany and Scott 2006). Australian population estimates and trends are unknown.

Wildlife Conservation Plan for Seabirds 135

The species is listed threatened in Victoria and New South Wales. Habitat loss, fragmentation and degradation through the development of foreshore poses a significant threat to the Little Tern, with relative sea level rises predicted due to climate change also threatening beach nesting habitats. Human disturbance at colonies will result in colony abandonment and catastrophic breeding failure. There is also potentially a risk from the spread of the invasive weed Sea Spurge (Euphorbia paralias); however, this does not seem to be significant at present. The Red Fox (Vulpes vulpes) acts as the main cause of breeding failure in New South Wales (NSW National Parks and Wildlife Service 2003). In some parts of the range, birds are also vulnerable to nest predation by Silver Gulls (Chroicocephalus novaehollandiae); this is typically following human disturbance that facilitates Sliver Gull attacks.