|Photo by Garry Bakker (PBase)|
Tristan thrush (en); tordo-de-Tristão da Cunha (pt); grive de Tristan da Cunha (fr); zorzal de Tristán da Cunha (es); Tristandrossel (de)
This species is endemic to Tristan da Cunha, in the South Atlantic Ocean, where it is found on Tristan, Inaccessible, Nightingale, Middle and Stoltenhoff islands.
These birds are 23 cm long and weigh 80-125 g.
Habitat:The Tristan thrush is found in all available habitats in the islands, including rocky shorelines, tussock grassland, fern-dominated scrublands, wet heathland and rural gardens. They are present from sea level up to an altitude of 300 m.
Diet:They are highly opportunistic, taking earthworms and other soil invertebrates, as well as, berries, dead birds, fish offal, kitchen scraps, and the eggs and fledglings of other birds including seabirds such as the Atlantic yellow-nosed albatross Thalassarche chlororhynchos, the great shearwater Puffinus gravis and the endemic spectacled petrel Procellaria conspicillata. They are even known to kill adult white-bellied storm petrels Fregetta grallaria and white-faced storm petrels Pelagodroma marina directly, probably by taking them from their burrows.
Tristan thrushes breed in September-February. The nest is a rough cup woven from tussock fronds and grass stalks with some moss and leaves, placed on or just above the ground. There the female lays 2-4 pale green eggs with reddish-brown spots. There is no available information regarding the incubation period, but the chicks are fed by both parents and fledge about 20 days after hatching.
IUCN status - NT (Near-Threatened)
This species has a small breeding range and a global population estimated at 1.500-7.000 individuals. The population is currently suspected to be stable as there is no evidence foor declines or serious threats. Still, predation by black rats Rattus rattus is a possible threat on Tristan, and translocations of birds between islands, a common practice in the past, resulted in hybridisation, which is another concern.