Sedge Warbler | Acrocephalus schoenobaenus

Voice

The song, also given by migrants in spring, is a fast, excited, varied series of harsh and pure notes, with repeated motifs and mimicry, often accelerating: cherr-cherr-tirri-tirri-chew-chew-trrrr. The call is a dry tsek and a rattling tschrrr when alarmed.

Identification

11.5–13 cm. Upperparts olive-brown with a dark-streaked mantle and an unstreaked, warm rufous-brown rump. The crown is dark, finely streaked and without a pale central stripe; below it a broad creamy-white supercilium extending well behind the eye, above a dark eye-stripe. Underparts off-white with ochre-buff breast sides and flanks. Juveniles in late summer are yellower, with a fine spotted breast band and sometimes a faint pale crown-stripe. Often holds the tail slightly fanned; makes short song flights, rising and gliding back down.

Confusion species

Moustached Warbler (Acrocephalus melanopogon) has an almost black crown, a broad, square-ended white supercilium, a more rufous mantle and shorter wings, and often cocks its tail. Aquatic Warbler (Acrocephalus paludicola), a rare migrant along Morocco's Atlantic coast, has a clear pale central crown-stripe and streaks on the rump; juvenile Sedge Warblers with a faint crown-stripe are the pitfall. Common Grasshopper-Warbler (Locustella naevia) has a faint supercilium, a rounded tail and undertail coverts with long pale fringes. Unstreaked reed warblers lack the mantle streaking.

Habitat

On passage in reeds and reedmace, rank vegetation along irrigation and drainage channels, wet fields of alfalfa and barley, tamarisks around oases and sewage works, even gardens. In late summer it seeks places with abundant reed aphids, on which it can almost double its weight before crossing the desert.

Range and movements

Passage migrant throughout the region, on a broad front across the Sahara. In spring (March – May) common in Morocco, Algeria, Tunisia, the oases of Libya and Egypt, along the Nile and in Sinai, in Israel, Jordan, Lebanon and Syria; in Iraq, Kuwait, Saudi Arabia, Bahrain, Qatar, the United Arab Emirates, Oman and Yemen a fairly common to common migrant. Autumn passage (July – October) is most conspicuous in the west, with large numbers in Moroccan coastal marshes. Does not breed in the region; a few wintering birds have been reported from Egypt and Israel. Breeds from western Europe to central Siberia and winters in sub-Saharan Africa.

• Resident
• Summer visitor (c. Apr–Sep)
• Winter visitor (c. Oct–Mar)
• Passage (Mar–Apr, Oct–Nov)
• dark = core range, pale = thinly spread

How and when to look

In late April in a reed marsh or irrigated field at the desert edge: Merja Zerga or Oued Massa in Morocco, the ponds at Eilat, the Hula, Azraq in Jordan or a sewage works in the Gulf states. A bird rising in song and gliding back with fanned tail is almost always a Sedge Warbler.

Conservation status

Not globally threatened. Survival depends strongly on rainfall in the Sahel; drainage of marshes and loss of reedbeds along the flyway in North Africa and the Middle East remove stopover sites.

Scientific name

Acrocephalus schoenobaenus | (Linnaeus, 1758)

Linnaeus described the species in 1758 as Motacilla Schoenobaenus; because it was later moved to another genus, the author and year stand in brackets. The genus Acrocephalus was introduced in 1811 by Naumann & Naumann. Acrocephalus is Greek, from akros 'topmost, pointed' and kephalē 'head'; the Naumanns, who introduced the genus, called these birds Spitzkopf 'pointed head', so they read akros as 'pointed'. schoenobaenus is Greek, from skhoinos, 'reed', and bainō, 'to tread'; it translates the old Swedish name Sävstigare. The specimen the first description was based on came from southern Sweden.