Acrocephalus: The Reed Warblers
Acrocephalus is a genus of small, insectivorous passerine birds that belong to the family Acrocephalidae. They are commonly known as reed warblers, because they often breed and feed in reed beds. They are found in Europe, Asia, Africa and Australia, and are mostly migratory, wintering in warmer regions.
The name Acrocephalus comes from Ancient Greek akros, “highest”, and kephale, “head”. It is possible that the Naumanns, who introduced the genus name in 1811, thought akros meant “sharp-pointed”.
There are about 40 species of reed warblers in the genus Acrocephalus, varying in size, color and habitat preferences. Some of the most widespread and well-known species are:
- The common reed warbler (Acrocephalus scirpaceus), which breeds across Europe into the temperate western Palaearctic and winters in sub-Saharan Africa. It has an unstreaked brown back and buff underparts, and a strong and pointed bill. It has a loud and varied song that often includes imitations of other birds.
- The marsh warbler (Acrocephalus palustris), which breeds in temperate Europe and the western Palearctic and winters mainly in southeast Africa. It is similar to the common reed warbler, but has a more olive-brown back and whitish underparts. It is notable for incorporating striking imitations of a wide variety of other birds into its song.
- The great reed warbler (Acrocephalus arundinaceus), which breeds in Europe, Asia and north Africa and winters in sub-Saharan Africa. It is the largest and most robust reed warbler, with a heavy bill and a long tail. It has a brown back and pale underparts with faint streaks on the breast. It has a loud and deep song that can be heard from far away.
Reed warblers are mainly insectivorous, feeding on insects and other small invertebrates that they find among the reeds or other vegetation. They also eat some seeds and berries. They build their nests in reeds or bushes, often over water, using plant material and spider webs. They lay 3 to 6 eggs, which are incubated by both parents for about two weeks. The chicks fledge after another two weeks, but remain dependent on their parents for some time.
Reed warblers are important indicators of wetland health, as they depend on reed beds and other aquatic habitats for breeding and feeding. They are also vulnerable to habitat loss, pollution, predation and climate change. Some species, such as the common reed warbler and the marsh warbler, are common and expanding their range in some areas, while others, such as the aquatic warbler (Acrocephalus paludicola) and the Seychelles warbler (Acrocephalus sechellensis), are rare and endangered.