#ThreatenedSpecies of the Week: Sternula nereis nereis (Australian Fairy Tern)

Photo Credit: BirdLife.
Photo Credit: BirdLife.

The main identified threats to the Sternula nereis nereis, or commonly know as the Australian Fairy Tern include predation by introduced mammals (foxes, cats, dogs, rats); disturbance by humans, dogs and vehicles; increasing salinity in waters adjacent to Fairy Tern colonies; irregular water management; and weed encroachment.

Sternula nereis nereis is listed as Vulnerable under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

The Australian Fairy Tern, is a small (22–27cm) grey and white bird with long, narrow wings and a bright orange bill which is often black at the base of the upper bill. The Fairy Tern has a bulky body with a round-bellied appearance, a large white forehead and the legs are yellow to orange-yellow. The space between the eye and bill is white with a black patch in front of the eye. It has a black crown, nape and pearly grey upperparts which blend into the whitish rump and tail.

 Non-breeding Fairy Terns have a dusky orange-brown bill which is blackish at the tip. The crown is white and the upper wing is the same as the breeding adult but the outer primary feathers are less contrasting with no dark shoulder bar. Juvenile Fairy Terns have a dark brown bill and legs. The crown is streaked dusky and buff with a dark ear patch. The outer wing is dark greyish and the inner wing is pale grey and white

The subspecies’ extent of occurrence is approximately 380 000 km2 as it occurs along the coasts of New South Wales, Victoria, Tasmania, South Australia and Western Australia. The area of occupancy is estimated to be 1150 km2. The total number of mature individuals of the Fairy Tern is estimated to be less than 5000 individuals. Fairy Terns utilise a variety of habitats including offshore, estuarine or lacustrine (lake) islands, wetlands, beaches and spits. The subspecies may migrate within southern Western Australia and Tasmania, where they are seen less frequently during the winter months.

The Fairy Tern feeds on small bait size fish including Engraulis australis (Anchovy), Sardinops neopilchardus (Pilchards) and Spratelloides robustus (Blue Sprats). They are also known to feed on plant material, molluscs and crustaceans in inshore waters around island archipelagos and on the Australian mainland.

Fairy Terns nest in small colonies on coral shingle on continental islands or coral cays, on sandy islands and beaches inside estuaries, and on open sandy beaches. They nest above the high water mark often in clear view of the water and on sites where the substrate is sandy and the vegetation low and sparse. Nests typically consist of a shallow scrape in the sand which is often lined with small shells and vegetation. Female Fairy Terns lay one to two eggs in a sand scrape. Colonies tend to occupy areas rather than specific sites, and nest sites are often abandoned after one year, even if they have been successful.

More information about Fairy Tern Conservation in South Western Australia can be found at http://www.ccwa.org.au/south_west_fairy_tern_project

Information Source: Government of Australia, Department of Environment and Department of Parks and Wildlife Western Australia

 

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