Sedge Warbler

Sedge Warbler, Rietzanger, Schilfrohrsänger, Felosa dos Juncos, Carricerín Común

Spotted in the Alentejo region of Portugal.                              Sedge Warbler sound

The Sedge Warbler (Acrocephalus schoenobaenus) is an Old World warbler in the genus Acrocephalus. It is a medium-sized warbler with a brown, streaked back and wings and a distinct pale supercilium. Sedge Warblers are migratory, crossing the Sahara to get from their European and Asian breeding grounds to spend winter in Africa. The male’s song is composed of random chattering phrases and can include mimicry of other species. The Sedge Warbler is mostly insectivorous.

This is a medium-sized warbler, 11.5-13 cm long and weighing around 12 g. It has a streaked brown back and wings, and pale underparts. The rump is warm brown and unstreaked, contrasting with the duller wings. The forehead is flattened, there is a prominent whitish supercilium, the crown is streaked with black, and the bill is strong and pointed. The legs are greyish.

The plumage of the sexes is identical, although they can be told apart when caught for ringing by the presence of a brood patch or cloacal protuberance. Juvenile birds have dark spots on the breast. They can be easier to confuse with Aquatic Warblers due to an apparent pale central crown stripe contrasting with the darker edges. Other similar species include Moustached Warblers and Pallas’s Grasshopper Warblers. The oldest recorded Sedge Warbler was a bird ringed in Finland which reached the age of 10 years, 1 month. The typical lifespan is 2 years.

The Sedge Warbler has a large range and an estimated Global Extent of Occurrence of 10 million square kilometres, with a large global population including between 8.8 million and 15 million birds in Europe. Data analysis by the British Trust for Ornithology has shown that fluctuations in the Sedge Warbler population stem from the adult survival rate, due to changes in rainfall on the birds’ wintering grounds. Global changes in population have not been measured, but the Sedge Warbler’s status is designated ‘of Least Concern’ by BirdLife International.

It breeds across Europe and western and central Asia and is migratory. After feeding up post-breeding, they migrate quickly across southern Europe and the Sahara from August to September. Studies in Nigeria and Uganda suggest that Sedge Warblers return to spend winter at the same sites, year after year.

All Sedge Warblers spend winter in sub-Saharan Africa, from Senegal in the west to Ethiopia in the east, and as far south as the eastern Cape Province of South Africa and northern Namibia. The route taken on the southward migration, and eventual wintering grounds, correspond to the birds’ breeding grounds. Birds ringed in the United Kingdom and Netherlands are later found from south-west Iberia to Italy; birds from Sweden are recovered in central Europe and Italy; while Finnish birds are found in north-east Italy and Malta east to the Aegean region. Sedge Warblers from the former Soviet Union take routes via the eastern Mediterranean Sea and Middle East.

Loss of wetland areas for feeding on migration, and the expansion of the Sahara desert, pose threats to the Sedge Warbler’s breeding population. Birds begin leaving Africa in late February, fatten up at wetlands before and probably after crossing the Sahara, and arrive in Europe from March onwards.

Unlike other members of the Acrocephalus genus, the Sedge Warbler’s range stretches from the Arctic to mid-latitudes. It is adapted to cool, cloudy and moist conditions. Though it is often found in wetlands, it can breed 500 metres or more away from water. During the breeding season, this is a species found in reedbeds, often with scrub, ditches and habitats away from water including hedgerows, patches of Stinging Nettles, and arable crops. On the African wintering grounds, habitats such as reeds at wetlands, papyrus, grass, sedge and reedmace and tall elephant grass are used. It can be found at altitudes of 1,800–2,400 metres above sea level in Ethiopia.

The song is varied, rushed and chattering, with sweeter phrases and some mimicry, typical of the Acrocephalus warblers. It is composed of phrases in random order, so that it is never the same. Male Sedge Warblers which have the widest repertoire mate with the largest number of females.

Male Sedge Warblers commence singing only a few hours after arriving on their breeding territory. The song is given from a bare perch such as a reed stem or bush, or from cover and during routine flights within their territory. Song-flights are also performed: while singing, the bird takes off, rises to a height of around 2–5 metres and then after a short circling flight, makes a slow, ‘parachuting’ descent, often with the wings held up in a ‘v’ shape. The song has the function of attracting a mate, rather than keeping other males away, and is stopped as soon as a mate is found. Contact calls are described as chirr or similar to Black-headed Gull keerrr; these calls are repeated quickly to form a rattling alarm call.

The male defends a territory of around 0.1 to 0.2 hectares; in a study at Zaanstad, Netherlands, 68 territories were studied, with an average size of 1064 metres square one year, and 904 m sq the next.[citation needed] The nest, built by the female, is in vegetation on the ground or up to a height of 50 cm. The cup-shaped structure has an outer layer of grass, stems and leaves, plus spiders’ webs, with a thick, finer layer inside including reed flowers, animal hair and plant down. It is woven around vertical plant stems. Between 3-5 greenish-yellow and brown-mottled eggs are laid, measuring 18 x 13 mm and weighing 1.6 g each. They are incubated by the female for 14 days; the chicks are altricial and naked. Both male and female care for the chicks, which fledge after 13–14 days. After leaving the nest, young Sedge Warblers continue begging for food from their parents for between 1–2 weeks after learning to fly.

Prey taken by Sedge Warblers includes mayflies, dragonflies and damselflies, grasshoppers, bugs, lacewings, moths, beetles and flies. Vegetable material includes elderberries and blackberries. On their wintering grounds food includes non-biting midges and flowers and berries from the Toothbrush Tree.

In late July, prior to migration, it appears that Sedge Warblers seek out sites with large numbers of Plum-reed Aphids and stay longer there than at other places; ringing studies show that birds may move considerable distances (e.g. from southern England to northern France) in search of food before beginning their actual migration. In Portugal, the aphid supply dries up too early for Sedge Warblers to utilise it, so many birds do not stop off there and are already heavy with fat when they pass through. Birds with the heaviest fat reserves built up before migration are capable of non-stop flights from Africa to southern Britain, or from Uganda to Iraq, for example. Some double their normal weight when ‘fuelling’ for migration. Lighter birds are forced to make the journey in several shorter parts.

Sedge Warblers feed in low, thick vegetation, especially reeds and rushes, but also in arable fields and around bushes. Feeding techniques include ‘picking’ insects from vegetation while perched or sometimes hovering, and ‘leap-catching’, when the bird grabs flying insects as it flies between perches. Sedge Warblers tend to hop between plant stems and pick insects from underneath leaves; they take advantage of the low temperatures around dusk and dawn which make their prey less mobile.

Other synonyms:

Afrikaans: Europese Vleisanger
Asturian: Carricín
Breton: Ar rouzard broenn
Catalan: Boscarla dels joncs, Boscarler pintat, Buscarla dels joncs
Catalan (Balears): Buscarla dels joncs
Valencian: Boscarler pintat
Czech: Rákosník proužkovaný
Welsh: Dryw’r hesg, Kedydd yr helvyg, Llwyd y gors, Llwyd yr hesg, Telor yr hesg
Danish: Sivsanger
German: Schilfrohrsaenger, Schilfrohrsänger, Schilf-Rohrsänger, Uferrohrsänger
Emiliano-romagnolo: Bech arvérs
English: European Sedge Warbler, European Sedge-Warbler, Sedge Warbler
Esperanto: junkokanbirdo
Spanish: Carricerin común, Carricerín Común
Estonian: Korkja-roolind, Kõrkja-roolind
Basque: Benarriz arrunt, Benarriz arrunta, Boscarla dels joncs
Finnish: Ruokokerttunen
Faroese: Sevljómari
French: Becfin des joncs, Phragmite des joncs
Irish: Ceolaire Cíbe
Gaelic: Glas-Eun
Galician: Avoceta, Boscarla dels joncs , Folosa dos xuncos
Manx: Arraneagh cliogee
Croatian: Trstenjak Rogožar
Hungarian: Foltos nádiposzáta
Icelandic: Síkjasöngvari
Italian: Forapaglie
Japanese: Suge yoshi-kiri, sugeyoshikiri
Cornish: Telor hesk
Kwangali: Niini
Latin: Acrocephalus phragmitis, Acrocephalus schoenobaenus, Acrocephalus schoenobaeus, Calamodus schoenobaenus
Limburgish: Sjprinkhaanzenger
Dutch: Rietzanger
Norwegian: Sivsanger
Polish: rokitniczka
Portuguese: felosa dos juncos, Felosa-dos-juncos
Romansh: Channarel da channa
Russian: Kamyshovka-barsuchok
Scots: Glas eun
Northern Sami: Goalšovizar
Slovak: Trsteniarik malý, trsteniarik pásikový
Slovenian: bicja trstnica
Albanian: Bilbilthi i zhukave
Serbian: trstenjak rogozar, Trstenjak rogožar
Swedish: Sävsångare
Swahili: Shoro Nyusi-nyeupe

Travel Birdwatching Holiday Alentejo, Vacation Portugal for birders to see birds on your trip.  

0 0 votes
Article Rating
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
Would love your thoughts, please comment.x