Western Olivaceous Warbler

The western olivaceous warbler (Iduna opaca), also known as the isabelline warbler, is a "warbler", formerly placed in the Old World warblers when these were a paraphyletic wastebin taxon. It is now considered a member of the acrocephaline warblers, Acrocephalidae, in the tree warbler genus Iduna. It was formerly regarded as part of a wider "olivaceous warbler" species, but as a result of modern taxonomic developments, this species is now usually considered distinct from the eastern olivaceous warbler, Iduna pallida.

Characteristics: It is a small passerine bird, found in dry open country, including cultivation, with bushes or some trees. Two or three eggs are laid in a nest in low undergrowth or a bush. Like most warblers, the western olivaceous warbler is insectivorous.

It is a medium-sized warbler, more like a very pale reed warbler than its relative the melodious warbler. The adults have a plain pale brown back and whitish underparts. Its body length is about , wingspan and weight . The bill is strong and pointed and the legs grey. The sexes are identical, as with most warblers, but young birds are more buff on the belly.

This species doesn´t wiggle its tail or does it uncommonly. Western olivaceous warbler searches for food at different heights.

It breeds in Iberia and north Africa. It is migratory, wintering in sub-Saharan Africa. It is a rare vagrant to northern Europe.

The western olivaceous warbler is larger and has a browner tinge to the upperparts than the eastern olivaceous warbler. It also has a larger bill. The song is a fast nasal babbling.

North Africa: The western olivaceous warbler occurs mainly as a passage migrant in southeast Morocco, although it also may breed in some densely vegetated areas there.