- Hippolais pallida
Includes Western Olivaceous/Isabelline Warbler (H. opaca). See section on Taxonomy.
Identification
Total length 12-15 cm (4½-6 in). 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.
Western race (see Taxonomy) is slightly larger, heavier-billed and browner than the eastern races.
Distribution
The western subspecies (see Taxonomy) breeds in Spain and north-western Africa from Western Sahara to north-western Libya. Winters in western Africa (mainly in the Sahel zone). Leave breeding grounds in July-October and return in March-April (North West Africa) or May (Spain).
The eastern subspecies breeds from the Balkans east through Greece, Crete, Cyprus, Turkey, Middle East, the Caucasus, to Iran and Afghanistan. In North Africa at scattered localities in inland Algeria and Tunisia (possibly also south-eastern Morocco), northern Libya and in the Nile Delta Valley and at scattered oases in the west of Egypt. Winter in Central and Eastern Africa, and south-western Arabian peninsula. Leave breeding grounds in July-September and return in April-May. Resident or only with local movements in Northern Somalia and parts of central, north-central and north-eastern Africa.
Vagrants have been recorded widely in the Western Palearctic in the British Isles, France, Germany, Sweden, Finland, Czechoslovakia, Italy, Malta, Canary Islands, Madeira and the Cape Verde Islands. Many of these will not have been subspecifically identified, but most in Europe are probably of the Eastern subspecies.
Several older British records have been rejected after a recent review but those that remain (c.10) have been referred to the Eastern subspecies. Most British records have been in the south-west in September-October although there have been records from the Northern Isles and the east coast.
Taxonomy
Five subspecies are recognized by the majority of world wide checklists and this is therefore still the position of Opus. Regional lists and Clements and IOC has split Olivaceous Warbler into two species based on mtDNA, song, morphology and behavior:
- Western Olivaceous/Isabelline Warbler (H. opaca).
- Eastern Olivaceous Warbler (H. pallida, with races reiseri, elaeica, laeneni and alulensis).
A Birdforum discussion includes statements that subspecies reiseri is vocally distinct from both opaca and elaeica[4].
Howard and Moore place this species in genus Iduna
For further, see Description, Distribution and Behavior.
Habitat
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.
Behaviour
When foraging, the eastern races flick their closed tail up-and-down; a habit lacking in the western race.
Diet
Feeds on insects and spiders. To lesser extend also fruits. Generally feeds at high levels, but sometimes lower on migration.
Breeding
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.
Vocalisation
<flashmp3>Hippolais pallida (song).mp3</flashmp3>
Listen in an external program
References
- 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
- Clements, JF. 2009. The Clements Checklist of Birds of the World. 6th ed., with updates to December 2009. Ithaca: Cornell Univ. Press. ISBN 978-0801445019.
- Gill, F, M Wright and D Donsker. 2009. IOC World Bird Names (version 2.0). Available at http://www.worldbirdnames.org/.
- Birdforum thread with links to pictures of different forms of Olivaceous Warbler
