Tuamotu Reed Warbler Acrocephalus atyphus Scientific name definitions

c. 18 cm. A slender brown reed-warbler with medium-length bill ; plumage highly variable, tending toward greyish and brownish colour morphs. Nominate race has whitish supercilium; generally grey-brown above, feathers often with fine dirty white margins, wings and tail slightly darker grey-brown but tipped with white; sometimes some white feathers scattered asymmetrically on wings, tail and/or head; whitish below; iris dark; upper mandible black, lower mandible pinkish; legs grey. Sexes similar. Juvenile unknown. Races differ mainly in measurements and, subtly, in shades of colour: <em>eremus</em> is larger than nominate, with much longer, downcurved bill , entire plumage heavily tinted with cinnamon; niauensis differs from nominate in being smaller, and almost lacking supercilium and the white feather margins of back; flavidus is larger than nominate, has upperparts slightly washed yellow, underparts strongly washed yellow; ravus differs from nominate in having underparts washed yellow.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Woodland and brush country on atolls and raised coral islands; occurs also in gardens, coconut (Cocos nucifera) plantations and Pandanus thickets.

Resident.

Mainly insects, including beetles (Coleoptera), flies (Diptera), hymenopterans; also spiders (Araneae), molluscs, crustaceans, small lizards, and some plant material. Forages by hopping rapidly up and down branches, pecking small items from twigs and leaves; forages also on the ground. Sometimes catches insects in flight.

Call a low “chru”, frequently repeated. Song usually consists of the “chru” call followed by a short whistling phrase, “chr-peee-tu-tu-pee-wee”, then a pause before being repeated with different arrangement of whistling notes; similar to that of A. caffer, but less rich and less varied.

Probably breeds throughout year, without distinct season. Territorial. Nest a deep cup of grass stems , twigs, long leaves and fine stems of vines, and coconut fibres, lined with delicate fibres and dry grasses, sometimes small green leaves, external diameter 9–13 cm, height 6–12 cm, internal diameter 5·5–8 cm, cup depth 3·5–4·5 cm, placed 1·5–10 m above ground in bush, among trailing vines or in tree (including coconut palm). Clutch 1–3 eggs; no information on incubation and nestling periods; both parents feed young.

Not globally threatened. Restricted-range species: present in Tuamotu Archipelago EBA. Locally common. In 1999, recorded as frequent to uncommon on Tuanake, Hiti, Tahanea and Tepoto; estimated density on small island of Tepoto in that year was 3·1 birds/ha.