It uses all the natural habitats available on the islands, including rocky shorelines, tussock grassland, fern-dominated shrubland and wet heathland.

[6] The thrush is thought to have evolved from an ancestor in the genus Turdus from South America, and resembles an immature austral thrush, but its adaptations to life on a small island group, including an unusual brush-tipped tongue modified for extracting the contents of eggs, have been used as reasons to warrant its separation into the monotypic genus Nesocichla.

[6] An opportunistic omnivore and scavenger, the thrush feeds on earthworms and other invertebrates of the soil and leaf litter, as well as on carrion, berries,[2] the eggs and fledglings of other birds, and kitchen scraps.

[6] In 2010 a paper published by Peter Ryan and Rob Ronconi in the journal Ardea reported an observation of Tristan thrushes breaking open an egg of the Atlantic yellow-nosed albatross.

[8] They saw evidence that the thrushes remove eggs of the spectacled petrel (a breeding endemic of Inaccessible Island) from their nesting burrows.

Conservation recommendations by BirdLife International are to continue regular population monitoring, to control rats on Tristan, and to prevent further introductions of mammalian predators.