Olive-tree Warbler Hippolais olivetorum Scientific name definitions

16–18 cm; 14–23 g. A large, elongate warbler with long strongish bill, long and fairly broad tail; long primary projection, about three-quarters (to equal) length of exposed tertials. Has very short and indistinct pale supercilium  (mainly a pale grey line above lores), pale eyering; crown and upper­parts grey with very slight brown tinge, flight-feathers and upperwing-coverts dark grey; edges of tertials  and secondaries white (prominent pale panel on closed wing); uppertail  and exposed primary tips noticeably dark grey (can appear blackish); outer rectrices with thin pale edges and white tips; off-white below  , diffuse grey tinge on breast and flanks, grey on lower flanks and undertail-coverts often becoming blotchy; iris dark; upper mandible greyish, lower mandible all yellowish, often with orange tinge; legs rather dark grey. Sexes alike. Immature is somewhat more strongly brown-tinged above than adult.

Mostly near coasts, from Croatia S to Greece and from extreme SE Romania and E Bulgaria S to W & S Turkey and W Syria, also N Israel; winters in E & S Africa.

Migratory. Spends non-breeding season in S Africa, chiefly from S Zambia S to N South Africa; rare overwinterer farther N, in Kenya and Tanzania. Departs from breeding grounds mid-Jul to early Sept, main passage through Israel mid-Jul to mid-Aug; at least some make stopover in little-known localities in NE Africa; passage through E Africa Oct–Dec, reaching South Africa in Dec. Spring return starts Feb–Apr, passage N through E Africa in Mar–Apr, through Israel mainly middle two weeks May; arrival on breeding grounds from early May, rarely late Apr.

Apparently mainly insects  and other invertebrates, and in summer some fruits and berries, including figs (Ficus); no detailed study yet made. Forages mostly in canopy of trees and tall bushes. As a consequence of its relatively large size, moves rather sluggishly in foliage, appearing rather “clumsy”, when feeding. Waves its tail to the sides, and also slightly vertically, in similar fashion to that of H. languida.

Song quite deep-voiced, hard and throaty, the raucous tone likened by some to that of both Acrocephalus arundinaceus and Fieldfare (Turdus pilaris): rather monotonous, a cyclically repeated phrase at moderate, staccato-like, jerky pace, with deeper notes and higher-pitched squeakier ones in recurring pattern; song phrases of variable length, often between 20 and 40 seconds, but many tentative and interrupted after 5–10 seconds if bird less inspired. Call a throaty, hard and deep, tongue-clicking “chuk”, on average a little deeper than calls of congeners, but may be subdued and more similar to those of H. languida; alarm a deep but nasal chattering, “kerrekekekek”, as if from a giant Blue Tit (Cyanistes caeruleus).