Australian Reed Warbler

The Australian reed warbler, Acrocephalus australis, is a modestly adorned bird, with a length spanning 15 to 18 centimetres. It is characterized by its drab brown plumage, which is subject to variation with the progression of wear. The species exhibits sexual monomorphism, meaning that males and females are visually indistinguishable.

Identification Tips

When observing this species, look for the short appearance of the wings that do not reach the uppertail-coverts. The beak is notably long and thin, with a subtle downward curve and a delicate hook at the tip. The tarsus and feet are elongated, contrasting with the short, feathered tibia. In fresh plumage, the bird boasts a russet brown hue from crown to back, with rufous uppertail-coverts and a tail measuring between 51 and 71 millimetres. The underparts are a duller rufous brown, while the throat and chin are adorned with white plumage. A pale brown supercilium is present, though it becomes less distinct as the plumage wears.

Habitat

The Australian reed warbler is found in a variety of wetlands, from fresh to saltwater environments. It favours dense vegetation with vertical structures, such as reeds, reedmace, and rushes, which provide suitable breeding and non-breeding habitats.

Distribution

This species is native to Australia and has been observed in Papua New Guinea and nearby islands. It is known to migrate seasonally within Australia, moving to the southwest and southeast regions for breeding.

Behaviour

The Australian reed warbler is a solitary forager, occasionally seen in pairs, and is known for its migratory habits, unlike other sedentary Acrocephalus species. It establishes breeding territories upon arrival at breeding grounds and engages in both polygynous and polyandrous relationships.

Song & Calls

The song of the Australian reed warbler is a melodious warble, interspersed with rich fluty and metallic notes. It is loud and varied, consisting of short sequences that are repeated with intervals, serving as a signal of the male's fitness and a means of territory defence.

Breeding

Breeding pairs are socially monogamous for the season, with both partners contributing to nest building and chick feeding. Nesting success is around 58%, with predation being the primary cause of nesting losses. The nest is a deep cup supported by reed stems, and incubation is solely performed by the female.

Diet and Feeding

The Australian reed warbler forages individually or in pairs, primarily on insects and spiders, with occasional consumption of molluscs and seeds. It gleans arthropods from dense riparian vegetation and surrounding shrubs and woodlands.

Conservation status

The species is currently listed as Least Concern by the IUCN. However, it is vulnerable to habitat loss through human activities such as burning, clearing, or draining of wetlands.