Tristan Thrush Turdus eremita Scientific name definitions

22–23 cm; 72–110 g. Nominate race is dull brown above with double orangey-spotted wingbars; below, orange-buff with lines of dark brown blotchy streaks, mid-buff vent; bill blackish; legs dusky-flesh. Sexes similar. Juvenile has pale buff spotting and streaking on upperparts. Race gordoni is larger than nominate, more spotted than streaked below, face paler and more flecked; <em>procax</em> is larger, darker, with darker orange underwing.

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Occupies wet heath, fern-bush, tussock grassland, gardens, and boulder-strewn shorelines.

Sedentary.

Opportunistic generalist and omnivore. Takes beetles, flies and maggots, caterpillars, spiders, mites, woodlice and earthworms; particularly fond of seabird eggs (tongue modified to extract contents), being able to open the eggs of birds as large as small albatrosses (4 Ryan, P. G., and R. A. Ronconi (2010). The Tristan Thrush Nesocichla eremita as seabird predator. Ardea 98(2):247–250. Close ), and plunders nestlings and fledglings of other landbirds, e.g. buntings (Crithagra) and Inaccessible Rail (Atlantisia rogersi); in Inaccesssible I removes from burrows and kills petrel chicks up to at least 70 g (4 Ryan, P. G., and R. A. Ronconi (2010). The Tristan Thrush Nesocichla eremita as seabird predator. Ardea 98(2):247–250. Close ); also dead seabirds, fish offal and kitchen scraps; seeds of Empetrum and Nertera, leaves of Phylica, marine algae; will even attack and kill adult White-bellied Storm-petrels (Fregetta grallaria) (5 Ryan, P.G. and Moloney, C.L. (1991). Tristan Thrushes kill adult White-bellied Storm-Petrels. Wilson Bull.. 103: 130-132. Close ). Forages on ground and on every available substrate within range, including close to surf zone on seashore.

Song a twittering combination of calls, “chissik, chissik, swee, swee, swee”. Calls include short hissing wheezy “swee” and soft chirping “chissik”.

Sept–Feb. Nest a rough cup of woven tussock fronds and grass stalks with a few green leaves and pieces of moss, placed on or just above ground at base of thick clump of Spartina, occasionally on cliff ledge. Eggs 2–3, sometimes 4 (race gordoni), pale turquoise with ginger-brown speckles and mauve blotches; no information on incubation period; fledging period c. 20 days.

Not globally threatened. Currently considered Near-threatened. Restricted-range species: present in Tristan Islands EBA. In 1972–1974, numbers estimated as 40–60 individuals on Tristan da Cunha, 100–500 on Inaccessible I, 300–500 on Nightingale I, 20–40 on Middle I and 10–20 on Stoltenhoff I; global total thus 470–1120. More recently, population on Tristan has been reckoned to number several hundred, that on Inaccessible 850 pairs, and global total c. 6000 individuals. Predation by black rat (Rattus rattus) may be a threat on Tristan da Cunha, where feral cats were a major problem before being eradicated. Nightingale I race <em>procax</em> was earlier introduced (illegally) on to Tristan when local population (nominate) had dropped to a just a few individuals.