The lesser swamp warbler or Cape reed warbler (''Acrocephalus gracilirostris'') is an

Old World warbler Old World warblers are a large group of birds formerly grouped together in the bird family Sylviidae. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the ci ...

in the genus '' Acrocephalus''. It is a resident breeder in

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

from the

Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

, the Chad and

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...

south to

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

. This is a common species of reedbeds in standing water.

Description

The lesser swamp warbler is a plain-coloured smallish bird 14–16 cm long and weighing around 20 g. Its upperparts are rich brown, and it has a white supercilium. The underparts are white, with a rufous wash to the flanks. The long, strong bill has a slightly down-curved upper mandible; it is blackish-yellow with a yellower base. The legs are blue-grey and the eyes are brown. Adults of both sexes and juvenile birds are very similar in appearance. The song is rich and melodious, a series of bubbly phrases that include trilling notes, ''cheerup chee trrreee'' and a large number of variations, with pauses between phrases.

Behaviour

The lesser swamp warbler builds a deep, firm cup nest from strips of reed blades, grass and sedges, which is lined with finer grasses. It is always placed in reeds above water. It nests mainly from August to December, with the earliest nesters being those in the winter rainfall areas of the Western

Cape Province The Province of the Cape of Good Hope ( af, Provinsie Kaap die Goeie Hoop), commonly referred to as the Cape Province ( af, Kaapprovinsie) and colloquially as The Cape ( af, Die Kaap), was a province in the Union of South Africa and subsequen ...

. It lays two or three brown eggs. This species is monogamous, pairing for life. The lesser swamp warbler is usually seen alone or in pairs, moving through

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The p ...

reedbeds, and clambering up and down reed stems. It eats insects and other small

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

Conservation status

This common species has a large range, with an estimated extent of 5,700,000 km². The population size is believed to be large, and the species is not believed to approach the thresholds for the population decline criterion of the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

(i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

Subspecies

''Acrocephalus gracilirostris'' includes the following subspecies:Gill F, D Donsker & P Rasmussen (Eds). 2020. IOC World Bird List (v10.2). doi : 10.14344/IOC.ML.10.2. * ''A. g. neglectus'' - (Alexander, 1908) * ''A. g. tsanae'' - (Bannerman, 1937) * ''A. g. jacksoni'' - (Neumann, 1901) * ''A. g. parvus'' - (Fischer, GA & Reichenow, 1884) * ''A. g. leptorhynchus'' - (Reichenow, 1879) * ''A. g. winterbottomi'' - (White, CMN, 1947) * ''A. g. cunenensis'' - (Hartert, 1903) * ''A. g. gracilirostris'' - (Hartlaub, 1864)

Gallery

Image: Acrocephalus gracillirostris Cape Reed Warbler Lesser Swamp Warbler 2012 05 08 6303.JPG, ''A. gracilirostris'' on perch in bulrush Image: Acrocephalus gracillirostris Cape Reed Warbler Lesser Swamp Warbler 2012 05 08 6315.JPG, ''A. gracilirostris'' scratching itself while preening

References

* Ian Sinclair, Phil Hockey and Warwick Tarboton, ''SASOL Birds of Southern Africa'' (Struik 2002)
SASOL e-guide

External links

* Lesser swamp warbler
Species text in The Atlas of Southern African Birds
{{Taxonbar, from=Q3727635 lesser swamp warbler Birds of Southern Africa Birds of Sub-Saharan Africa lesser swamp warbler lesser swamp warbler