LC
Olive-tree Warbler Hippolais olivetorum



Justification

Justification of Red List Category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Population justification
In Europe (which covers c.90% of the breeding range), the breeding population is estimated to be 10,800-25,000 pairs, which equates to 21,500-50,100 mature individuals (BirdLife International 2015). So a very preliminary estimate of the global population size is 23,800-55,600 mature individuals, although further validation of this estimate is needed.

Trend justification
In Europe the population size is estimated to be stable (BirdLife International 2015).

Ecology

This species inhabits orchards of almond (Prunus dulcis), olive (Olea) and pistachio (Pistacia vera), open oak (Quercus) woods, maquis on mountain slopes, savanna-like open woods and sparse trees on grassland, and similar. The presence of some taller trees is preferred. Breeding occurs from May to June. The nest is a well-built, deep cup of grasses, plant stems and soft twigs, often covered with cobwebs and lined with fine fibres, plant down, fur and similar soft material. It is sited in the fork of a branch of a tree. Clutches are three or four eggs. It is thought to mainly feed on insects and other invertebrates, and in the summer it also takes fruits and berries, including figs (Ficus). The species is migratory, wintering in southern Africa (Svensson 2006).

Threats

The ecology of this species is not well known, however it may be threatened by changes in habitat structure, especially from clearance and thinning of woodland and agricultural intensification in olive-groves and fruit plantations. Agricultural pesticide use may decrease insect prey numbers. In addition, bird trapping in Greece may impact the species (Tucker and Heath 1994).

Conservation actions

Conservation Actions Underway
CMS Appendix II. Bern Convention Appendix II. EU Birds Directive Annex I. There are currently no known conservation measures for this species within Europe.

Conservation Actions Proposed
Due to economic and cultural factors, the habitat of this species is likely to remain non-threatened, although it is essential that funding to assist olive production should favour old traditional plantations and management. Studies should look at the impact of the intensification of agriculture and forestry and the use of broad spectrum pesticides should be avoided. A survey of the species’s population status is needed, as well as research on its ecological requirements (Tucker and Heath 1994).

Acknowledgements

Text account compilers
Ashpole, J, Butchart, S., Ekstrom, J.


Recommended citation
BirdLife International (2021) Species factsheet: Hippolais olivetorum. Downloaded from http://www.birdlife.org on 08/12/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/12/2021.