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Western Olivaceous Warbler - BirdForum Opus

Photo © by Kevin Wade
Fuengirola, Málaga Spain, August 2020

Alternative name: Isabelline Warbler

Iduna opaca


Total length 13.5-15 cm, weight 9-17 g
Bill rather long and forehead "flat". Tail relatively long and square-endeed (sides rounded). Primary extention ca. ½ tertial-length. Dull greyish-brown above, whitish below with a dull greyish-brown tinge to flanks and chest. Eye-ring, lores and poorly marked supercilium buffy-white. Upper mandible blackish, lower dull orange-yellow.

Similar species

Slightly larger, heavier-billed and browner than Eastern Olivaceous Warbler.


Breeds in Spain and northwestern Africa north of the Atlas Mountains, from Western Sahara to north-western Libya. Winters in western Africa, mainly in the Sahel zone. Leave breeding grounds in July to October and returns in March or April (northwest Africa) or May (Spain).


This is a monotypic species.
It was formerly considered conspecific with Eastern Olivaceous Warbler, and was, along with the other species of Iduna, included in the genus Hippolais.

A Birdforum discussion includes statements that the Eastern Olivaceous Warbler subspecies I. p. reiseri is vocally distinct from both Western Olivaceous and I. p. elaeica[4].


Wide range of wooded and brushy habitats. Prefers areas with some tall trees and dense undergrowth, but avoids closed forest. Often near water. Fairly common in most of its range, but more scarce in Spain.


When foraging, does not flick its closed tail up-and-down, unlike Eastern Olivaceous Warbler.


Feeds on insects and spiders. To lesser extend also fruits. Generally feeds at high levels, but sometimes lower on migration.


The nest is a cup made of plant-material placed fairly low in the fork of a branch. The 3-5 eggs are incubated by the female, but both parents feed the nestlings.


  1. Dickinson, EC, ed. 2003. The Howard and Moore Complete Checklist of the Birds of the World. 3rd ed., with updates to October 2008 (Corrigenda 8). Princeton: Princeton Univ. Press. ISBN 978-0691117010
  2. Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2019. The eBird/Clements Checklist of Birds of the World: v2019. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
  3. Gill, F, M Wright and D Donsker. 2009. IOC World Bird Names (version 2.0). Available at http://www.worldbirdnames.org/.
  4. Birdforum thread with links to pictures of different forms of Olivaceous Warbler

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