Acrocephalus melanopogon (Temminck, 1823)

Taxonomy and Size

The moustached warbler, scientifically Acrocephalus melanopogon (Temminck, 1823), measures 12–13 cm (4.7–5.1 in) in length, making it slightly smaller than the closely related sedge warbler (Acrocephalus schoenobaenus).

Adult Plumage (Back and Underparts)

Adult moustached warblers have a finely streaked brown back and white underparts.

Adult Head and Bill Features

They have a flattened forehead, a prominent whitish supercilium, grey ear coverts, and a strong, pointed bill.

Sexual Plumage Dimorphism

Like most warbler species, males and females have identical plumage.

Juvenile Plumage

Juvenile birds are more heavily streaked overall and have additional markings on their breasts.

Song General Characteristics

The song of the moustached warbler is fast, and bears similarity to the songs of the sedge warbler and reed warbler.

Song Content and Genus Traits

It incorporates some vocal mimicry along with the characteristic whistles common to species of the Acrocephalus genus.

Song Comparison to Relatives

Compared to the songs of its close relatives, the moustached warbler's song is softer and more melodious, and includes phrases that sound similar to the song of a nightingale.

Song Behavior

Unlike the sedge warbler, the moustached warbler does not sing while in flight.

Northern Range Status

In areas north of its core range, the moustached warbler is scarce.

Vagrant Records (Northern Europe)

It has been recorded as a very rare vagrant as far north as Poland and Denmark.

British Records

A small number of reports have come from Great Britain, including a record of a breeding pair in Cambridgeshire in 1946.

British Record Delisting

These British records have recently been removed from the official list of British birds, as they could not be convincingly distinguished from records of sedge warblers or paddyfield warblers.

Habitat

This species inhabits areas with upright aquatic vegetation, such as reeds and sedge.