Family Typical Antbirds (Thamnophilidae)

Least Concern

Undulated Antshrike (Frederickena unduliger)


French: Batara ondé German: Dunkelameisenwürger Spanish: Batará ondulado

Thamnophilus unduliger


, 1868,

Rio Içanna, north-west Brazil


Races defined on basis of female plumages, but racial assignment of specimens often difficult because of extensive individual (though possibly age-related) variation, even among females from same locality. Form fulva recently elevated to species level#R on basis of slower (effect size 3.55; score 2), more rising (effect size 3.9; score 2) loudsong#R, but plumage differences between fulva and adjacent diversa very difficult to determine. Emendation of specific epithet to “unduligera” is unjustified#R. Four subspecies recognized.

Subspecies and Distribution
  • F. u. fulva J. T. Zimmer, 1944 – Fulvous Antshrike – SE Colombia (E Cauca, W Caquetá, W Putumayo), E Ecuador and E Peru (N of R Marañón and R Amazon), possibly extending E into Brazil (Amazonas N of R Solimões).
  • F. u. unduliger (Pelzeln, 1868) – Undulated Antshrike – NW Amazonian Brazil on upper R Negro, possibly extending S to N bank of R Solimões.
  • F. u. diversa J. T. Zimmer, 1944 – E Peru (S of R Marañón and R Amazon), NW Bolivia (S La Paz, extreme S Beni) and W Amazonian Brazil (S of R Amazon, E to R Juruá).
  • F. u. pallida J. T. Zimmer, 1944 – SW Amazonian Brazil (S of R Amazon, R Purus to R Madeira), probably also NC Bolivia (E Pando).
  • Descriptive notes

    23 cm; 75–85 g. Prominent crest; iris colour varies from brown to pale yellow, possibly related to age or population, or to both. Male is black, with irregular fine... read more


    Loudsong varies regionally: race fulva gives a long series (e.g. 7–20 notes, 4... read more


    Dense understorey of lowland evergreen forest, to 1100 m. Almost always associated with dense... read more

    Food and feeding

    Not well known. Feeds on a variety of insects, including beetles (Coleoptera), katydids and grasshoppers (Orthoptera) and hairy... read more


    Little information. A nest of race fulva found in NE Ecuador was a large, thin-walled cup made of rootlets, attached by the rim to... read more


    None recorded; presumed resident throughout its range.

    Status and conservation

    Not globally threatened (Least Concern). Seemingly an uncommon to rare, low-density species throughout most of its range, which includes vast areas of intact suitable habitat... read more

    Recommended citation

    Zimmer, K., Isler, M.L. & de Juana, E. (2020). Undulated Antshrike (Frederickena unduliger). 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 26 February 2020).