Chestnut-backed Antbird Poliocrania exsul

  • Order: Passeriformes
  • Family: Thamnophilidae
  • Polytypic: 5 subspecies
  • Authors: Stefan Woltmann, Ryan S. Terrill, Matthew J. Miller, and Matthew L. Brady

Demography and Populations

Age at first breeding

Nothing published. Of 54 formative-plumaged individuals, 5 (9%) had cloacal protuberances (CP), brood patches (BP) or both (compared to 30% of basic-plumaged captures during the same study [N = 222]; SW unpub. data). Depending on how long birds retain formative plumage, birds < 1 year are likely reproductively mature, as in Bicolored Antbird (Gymnopithys leucaspis; Willis 1967) and Song Wren (Cyphorhinus phaeocephalus; Robinson 2000).

Life span and survivorship

Little published. Two banded individuals in Panama lived 10.6 and 10.7 years (Willis 1983), though these presumably were cited as extremes. Ongoing study in Costa Rica suggests annual adult apparent survival is ca. 0.80, which implies an average lifespan of 4.24 years (mean life span = 1/-ln(s), where s = annual survival; Brownie et al. 1985).

Diseases and body parasites

Ticks (Ixodidae; Amblyomma spp., Haemaphysalis leporispalustris) noted in Costa Rica (Calderón et al. 2005). Ticks occasionally found on the head, small red or yellow mites (?) occasionally found around cloacal region (SW, RST, MLB pers. obs.). No blood parasites found in 9 individuals sampled in southern (Caribbean) Costa Rica (Benedikt et al. 2009).


Nothing published. Ongoing study in Costa Rica suggests breeding dispersal events rare and typically < 1 km; natal dispersal probably typically < 2 km (SW unpub. data).

Population regulation

Not well known (see also Predation). Nest failure rates high: 1 out of 4 of Skutch's (1969) and 1 of 6 of Willis and Oniki’s (1972) observed nests fledged young; 9 observed nests failed in a study on BCI (Robinson et al. 2005), and 4 observed nests failed in Costa Rica (Young et al. 2008). Population regulation in similar species may be most heavily dependent on predation during the egg, nestling, and post-fledging stages (e.g., Roper 1996, 2005), but survival at these different stages remains largely unquantified.

Recommended Citation

Woltmann, S., R. S. Terrill, M. J. Miller, and M. L. Brady (2010). Chestnut-backed Antbird (Poliocrania exsul), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.