Marsh Warbler

Identification

This is a medium-sized warbler. It is very similar in appearance to several other acrocephaline warblers, such as the reed warbler which also occurs in wetlands and has a similar breeding range. The male's distinctive song is useful for identification, as no other member of the genus mimics other birds to any significant extent. The marsh warbler also tends to avoid the stands of pure reed which are the reed warbler's favoured habitat. The sexes are alike in appearance. Hybridisation with both reed warbler and Blyth's reed warbler has been occasionally recorded.<p>The marsh warbler is best known for the highly imitative song uttered by males, and very occasionally by females. Each male marsh warbler incorporates imitations of a wide range of other birds into its song. Other passerines are most commonly imitated, but the calls of other kinds of bird such as waders, hornbills and pigeons have been noted too. On average, each male bird incorporates imitations of 75 other species into its song, with rather more African than northern species mimicked. All learning seems to take place in the summer the bird is hatched in Europe or Asia, and in its first winter in Africa. The calls of birds heard in subsequent years are not added to the warbler's repertoire. Females may utter a simple, non-imitative song, and a range of other calls are also known.

Taxonomy

The marsh warbler was formally described in 1798 by the German naturalist Johann Matthäus Bechstein under the scientific name Motacilla s. Sylvia palustris.The type locality is Germany. The marsh warbler is now one of around 40 species placed in the genus Acrocephalus that was introduced by Johann Andreas Naumann and his son Johann Friedrich Naumann in 1811. The genus name Acrocephalus is from Ancient Greek akros, "highest", and kephale, "head". It is possible that the Naumanns thought akros meant "sharp-pointed". The specific palustris is from Latin and means "marshy". The species is considered as monotypic, and there is no significant geographical variation.

Scientific name

Acrocephalus palustris

Authority

(Bechstein, 1798)

Order

Passeriformes

Family

Acrocephalidae

Genus

Acrocephalus

Range and habitat

The marsh warbler breeds in the middle latitudes of Europe and western Asia, from the English Channel to about 70 degrees east. It mainly occupies areas with a continental climate, but breeds, or has bred, in Britain and northern France as well. It is principally a bird of the lowlands, but occurs at altitudes of up to 3000m in Georgia. In recent decades it has expanded its range to the north, with increasing numbers of birds breeding in Scandinavia and north-west Russia. Singing males are occasionally heard in Ireland, most recently in 2017.<p>In western Europe the marsh warbler breeds mainly in rank vegetation on damp or seasonally flooded soils, and is particularly attracted to tall herbaceous vegetation such as nettles, meadowsweet, willowherbs and to young osiers and other low woody plants. It may breed in urban brownfield sites with suitable vegetation, for instance in Berlin, and also occasionally in arable crops. In the eastern part of its range, it breeds on dry hillsides with shrubs and in open woodland, as well as the kind of damper habitats it frequents in the west.<p>The marsh warbler winters mainly in south-east Africa, from Cape Province north to Zambia and Malawi. It makes use of a range of well-vegetated habitats, from moist scrub to dense thickets and woodland edge, at altitudes up to 2400m. Marsh warblers tend to migrate from Europe to Africa via the Middle East, with many crossing Arabia and arriving in Africa on Sudan's Red Sea coast. Adults usually leave their breeding grounds soon after their young are independent, with their offspring following about two weeks later. On the Red Sea coast most birds arrive from mid-August to mid-September, with numbers of adults peaking in August and of young birds in September. Birds tend to spend much of the autumn somewhere in north-east or east Africa, before continuing south to arrive on their wintering grounds in December or January.<p>In spring, marsh warblers leave their wintering grounds in March or April. They are thought to follow broadly similar routes to their autumn migration. Birds breeding in south-east Europe, for instance on the Black Sea coast, may arrive there by late April. In other parts of their range, the majority of birds do not arrive until mid-May. On the western and northern edge of their range, such as in England, birds do not tend to arrive until the end of May or early June.<p>As a vagrant, the species has been recorded as far away as Iceland and Madeira.

Breeding range

PAL : c, nc Europe to ec Russia and s to Turkey and Iraq

Non-breeding range

e, se AF

Migration

Complete migrants

Behavior

Migration pattern: Complete migrants.

Conservation

Population trend: stable.

Population trend

stable