The Fly River grassbird is a species of Old World warbler in the family Locustellidae. It is found in Indonesia and Papua New Guinea. Its natural habitats are freshwater marshes and lakes. It is threatened by habitat loss.
Region
New Guinea southern lowlands
Typical Environment
This species inhabits extensive freshwater marshes, lake margins, and slow-moving river floodplains with tall grasses, sedges, and reeds. It is closely associated with dense emergent vegetation, including canegrass, sedgelands, and stands of Phragmites and other reeds. Birds are typically found along the lower Fly River system in Papua New Guinea and in comparable lowland wetlands of southern Papua (Indonesia). It prefers areas with shallow water and floating or tussocky vegetation that provide cover and nest sites.
Altitude Range
Sea level to 500 m
Climate Zone
Tropical
Ease of Keeping
Beginner friendly: 1/5
The Fly River grassbird is a highly localized reed and marsh specialist restricted to the lowlands of New Guinea. It is notoriously skulking and more often detected by its reeling song than seen. Ongoing loss and degradation of wetlands through drainage, burning, and development pose serious threats to its small, fragmented population.
Temperament
shy and skulking
Flight Pattern
short rapid wingbeats, low over reeds
Social Behavior
Typically seen singly or in pairs, moving mouse-like through dense grasses and reeds. During the breeding season, males sing from concealed perches within emergent vegetation. Nests are placed low in dense sedge or reed clumps, where 2–3 eggs are laid and both parents likely assist in care.
Migratory Pattern
Resident
Song Description
Song is a reeling, insect-like series of buzzy trills and rattles delivered from hidden cover. Calls include thin tzik notes and soft chatters, often given when flushed.
Plumage
Upperparts warm brown with fine darker streaking; underparts buffy to whitish with paler throat and belly. Feathers often show pale or whitish edging, giving a subtly scalloped look. Tail is relatively long and graduated, with narrow pale margins.
Diet
Feeds primarily on insects and other small arthropods such as beetles, grasshoppers, crickets, and spiders. It gleans prey from stems and leaves and occasionally snaps at small flying insects with short sallies. Foraging is deliberate and close to cover, taking advantage of dense vegetation to remain concealed.
Preferred Environment
Most feeding occurs within thick sedges, reeds, and tall grasses along wetland edges and shallow floodplains. It also uses floating mats of vegetation and tussocks that provide both foraging substrates and escape cover.
