Eastern Olivaceous Warbler Iduna pallida Scientific name definitions

12–14 cm; 8–16 g. A grey-brown <em>Hippolais</em> with rather narrow and square-ended medium-long tail , and fairly long and pointed strong-based bill not unlike that of Acrocephalus scirpaceus. Nominate race has short and poorly marked whitish supercilium reaching back to rear edge of eye, whitish eyering; crown and upperparts uniformly warm brownish-grey or pale brown with slight rufous tinge; tertials and secondaries in fresh plumage often with paler edges (faint hint of pale panel on closed wing); tail with diffusely paler edges and tips of outer feathers; off-white below, faint buff-grey hue on breast side and flanks; iris dark brown; upper mandible largely dark, lower mandible all pinkish-yellow; legs greyish, sometimes with slight pinkish or pale brown tinge. Differs from I. rama mainly in proportionately slightly bigger head and thicker neck, longer primary projection, slightly shorter tail. Sexes alike. Immature resembles adult. Races differ mainly in tone of colour and in size: <em>elaeica</em> is largest, with longest primary projection and darkest flight-feathers, tends to be greyer above than others, often with olive tinge in fresh plumage, and to have the most pronounced pale secondary panel (fresh plumage); <em>reiseri</em> is slightly paler than nominate, pale sandy brown above, with rather obvious pale brown secondary panel; laeneni is very similar to previous, but slightly paler and smaller; alulensis is similar to last in size, but darker and greyer above, supercilium and underparts less buff-tinged.

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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.

Mainly invertebrates; some fruits. Invertebrates include e.g. dragonflies (Odonata), grasshoppers (Orthoptera), termites (Isoptera), bugs (Hemiptera, including aphids), moths and butterflies (Lepidoptera), various dipteran flies, ants (Hymenoptera), beetles (Coleoptera), and spiders (Araneae); larvae of beetles and butterflies taken in summer. Fruits eaten in late summer, include berries of bramble (Rubus fruticosus) and elder (Sambucus), among others. Takes prey from leaves and twigs while energetically searching the canopy; stretches its neck and picks with bill in fast movements. Will sometimes drop to the ground and take food items there. On migration, unlike at breeding sites, frequently feeds in very low scrub. Has peculiar habit, especially when foraging and moving through bushes or canopy, of repeatedly flicking or “dipping” its folded tail rapidly downwards and back again; often, each tail-dip accompanied by a call.

Song a fairly loud, characteristic, scratchy , monotonous phrase cyclically repeated, with low hoarse and scratchy notes followed by some higher-pitched, nasal or squeaky ones, then back to lower scratchy notes, and so on at steady, leisurely pace; notes a bit slurred, running into each other (song not “well articulated”), phrases vary between c. 10 seconds and 30 seconds, at times much longer; geographically only small variation, despite large range. Call a throaty tongue-clicking “chek” with nasal undertone, sometimes prolonged to slurred trills, “cher’r’r’r”.