Thick-billed Warbler (Iduna aedon)

Thick-billed Warbler

[order] PASSERIFORMES | [family] Acrocephalidae | [latin] Iduna aedon | [UK] Thick-billed Warbler | [FR] Rousserole a gros bec | [DE] Dickschnabel-Rohrsanger | [ES] Carricero picogordo | [NL] Diksnavelrietzanger


Genus Species subspecies Breeding Range Breeding Range 2 Non Breeding Range
Iduna aedon EU nc, ne Southeast Asia
Iduna aedon aedon
Iduna aedon rufescens

Physical charateristics

Less bulky than Great Reed Warbler, with noticeably shorter bill, more domed (less angular) head, much shorter wings, and longer and distinctly more graduated tail; structure distinctive, with weight apparently set forward and rump and tail looking relatively narrow or slight. Large, stubby-billed warbler, with less full rear body and tail than Great Reed Warbler; plumage similarly uniform warm olive-brown over fore-parts and wings but can appear markedly rufous over rump and tail. Lacks contrasting supercilium. Cocks tail.

Listen to the sound of Thick-billed Warbler

[audio: Warbler.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 21 cm wingspan max.: 24 cm
size min.: 18 cm size max.: 19 cm
incubation min.: 0 days incubation max.: 0 days
fledging min.: 0 days fledging max.: 0 days
broods: 1   eggs min.: 4  
      eggs max.: 6  


Eurasia : nc, Northeast


Breeds extralimitally in middle latitudes of east Palearctic, mainly in dry warm continental lowlands. Prefers thickets of bushes to reedbeds, independently of presence of water.


Only limited information. 5-6 eggs are laid in a nest in a low tree

Feeding habits

Like most warblers, it is insectivorous, but will take other small prey items.


This species has a large range, with an estimated global Extent of Occurrence of 1,000,000-10,000,000 km2. The global population size has not been quantified, but it is believed to be large as the species is described as ‘frequent’ in at least parts of its range (Baker 1997). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.
Breeds in Asia from Ob? river and northern Mongolia east to Ussuriland and north-east China. Accidental in Britain: single birds, Shetland, October 1955 and September 1971. Finland: one, Norrsk

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