The fairy tern (Sternula nereis ) is a small tern which is native to the southwestern Pacific. It is listed as "Vulnerable" by the IUCN and the New Zealand subspecies is "Critically Endangered".
There are three subspecies:
Weighing just 70 grams as an adult, the Fairy tern is one of Australasia’s smallest terns. At the time of the breeding season, this little seabird has a black head, an orange/yellow bill, upperparts of pale gray, a white throat, forehead, chest and belly, and orange legs. Outside of the breeding season, the head fades to mottled black and white, and its bill and legs become less bright in color. Male and female have a similar appearance, and juveniles look like non-breeding adults.
Fairy terns are found on the coast from Dampier Archipelago in Western Australia, south to Tasmania and Victoria, with individuals sometimes found on the east coast. They are most commonly found in Western Australia and are rare in New South Wales, the Northern Territory and Queensland. Some may be found in New Caledonia and New Zealand. They occur on coastal beaches, offshore and inshore islands, sheltered inlets, harbors, estuaries, lagoons and sewage farms. They like both saline and fresh wetlands, as well as near-coastal terrestrial wetlands, such as lakes and salt-ponds.
Fairy terns hunt while flying, hovering above the surface of the sea at three to ten meters, before they plunge steeply into the water, to emerge seconds later. They do not often go far out to sea and are usually seen where predatory fish feed on schools of small fish. These birds are often seen in pairs flying around trees and they use trees for breeding, but do not make a nest. The migratory behavior of these birds is not well understood. Some populations, such as in Tasmania, migrate over winter, while others seem to stay year round in the same area.
Fairy terns are carnivores (piscivores), they mostly eat fish, but also crustaceans, snails and plant material.
Fairy terns are monogamous breeders with long-lasting pair bonds. They are very loyal to their mates, their nest sites and their foraging areas. September is when courtship begins, with eggs being laid from late October to early January. Females are supplementary-fed by their mates before laying. In Australia these fairy terns breed in colonies, including some fairly large ones, but in New Zealand pairs usually nest alone, with several kilometers between nests. One to two eggs usually are laid each season, though if a clutch is lost, the pair generally re-nests. Both parents share incubation duties, which last for around 21 days. The chicks are on the move from day one. Both male and female feed and guard the young, the male providing most of the food. At about 30 days chicks fully fledge, being fed less and less often by their parents for one more month while learning to forage for themselves. Most family groups by this time have left their breeding estuaries.
Over much of its range, fairy terns are subject to a number of threats, including human disturbance, predation from introduced species, habitat degradation due to farming and development, and extreme weather events.
According to the IUCN Red List, the total Fairy tern population size is around 2,500-9,999 mature individuals. Specific populations of this species have been estimated in these areas: in Australia: at up to 170 sites, fewer than 5,000 mature birds, in Western Australia fewer than 1,600 pairs, in Tasmania and in South Australia, a few hundred pairs, and in Victoria just a few pairs; in New Zealand: 35-40 pairs; in New Caledonia: 100-200 pairs. Overall, currently Fairy terns are classified as Vulnerable (VU) and their numbers today continue to decrease.
