Family Reed-warblers (Acrocephalidae)

Least Concern

Thick-billed Warbler (Arundinax aedon)


French: Rousserolle à gros bec German: Dickschnabelspötter Spanish: Carricero picogordo

Muscicapa Aëdon


, 1776,

south-eastern Transbaikalia, eastern Siberia, Russia


If species is classified in Acrocephalus, name rufescens becomes preoccupied and must be replaced by stegmanni. Races may intergrade; rufescens only doubtfully valid#R. Two subspecies recognized.

Subspecies and Distribution
  • A. a. aedon (Pallas, 1776) – SC Siberia (from Tomsk E to Kansk, S to L Teletskoy in Altai and to E Sayan Mts) and adjacent NW Mongolia; non-breeding Nepal and E & S India E to Myanmar and Thailand.
  • A. a. rufescens (Stegmann, 1929) – E Siberia and NE Mongolia E to Sea of Japan, S to NE China; non-breeding S China, Thailand and Indochina.
  • Descriptive notes

    18–21 cm; 22–31 g. A large unstreaked reed-warbler with short, stout bill (decurved upper mandible), plain head pattern, tail appearing long and graduated and... read more


    Song a ticking “tschok tschok” followed by loud, hurried, chattering warble of harsh and more... read more


    Breeds mainly in dry warm continental lowlands, utilizing dense thickets, bushes, tall grass, edges... read more

    Food and feeding

    Mostly insects, including many grasshoppers (Orthoptera). Items recorded in nestling diet were small caterpillars, large caterpillars of... read more


    In SE Russia, laying from mid-Jun to 2nd Jul in Amurland and full clutches of fresh eggs recorded between 13th Jun and 10th Jul in... read more


    Migratory. After breeding, migrates S through Mongolia and E China to winter quarters in S Nepal,... read more

    Status and conservation

    Not globally threatened. Generally uncommon but widespread. In C Siberia, rare in Sayan but more numerous E & S of L Baikal; common in valleys of R Amur and R Ussuri.... read more

    Recommended citation

    Dyrcz, A. (2019). Thick-billed Warbler (Arundinax aedon). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 18 February 2019).