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Grallaria ruficapilla

Chestnut-crowned Antpitta

  • Order: Passeriformes
  • Family: Grallariidae
  • Polytypic 7 Subspecies

Authors: Greeney, Harold F., and Guy M. Kirwan

Life History

Food

Diet not well documented, but almost certainly dominated by invertebrates. Like others in the genus, earthworms are likely important for adults and for feeding young in the nest. In support of this, Chestnut-crowned Antpittas easilyare  trained to take earthworms proffered at feeding stations.

Behavior

Like all antpittas, the behavior of Chestnut-crowned Antpittas is poorly documented, and no aspect has ever been quantified. Nevertheless, as one of the most easily observed species, we know that Chestnut-crowned Antpittas frequently forage on the ground for invertebrate prey, but also occasionally climb to several meters above the ground in search of caterpillars and other foliage-dwelling invertebrates (Krabbe and Schulenberg 2003). Like their congeners, this species is generally shy, but may respond strongly to a whistled imitation of their song. Otherwise they remain well hidden in thick vegetation, low to the ground. This species is known to occasionally follow army ant swarms, and it has been postulated that it may regularly follow large terrestrial mammals (e.g., Spectacled Bears, Mountain Tapirs), as a facultative means of searching for prey items in the earth and vegetation disturbed by the larger animal (Greeney 2012).  Greeney (2012) also reported that Chestnut-crowned Antpittas seemed actually to be attracted to the sound of humans crashing through bamboo, but no detailed studies have examined or quantified this behavior.

Territoriality

Territories in Colombia are estimated to be about 2 ha (Kattan and Beltran 1999, 2002), but little is known about behavioral aspects of territory defense or maintenance.

Sexual Behavior

Not described, probably monogamous.

Social and interspecific behavior

Nothing known. It appears that this species rarely joins mixed species flocks, but it occasionally has been observed attending swarms of highland army ants (Labidus sp.) (Greeney 2012).

Predation

No information.

Reproduction

Nest. Despite the description of the eggs of Chestnut-crowned Antpitta from several parts of its range (see below) there are only two published descriptions of its nest. In Sclater and Salvin (1879), T. K. Salmon described a nest of G. r. ruficapilla from Antioquia, Colombia as "a mass of roots, dead leaves, and moss, lined with roots and fibers [ ] placed at some height from the ground." Apart from this rather cursory description, only one other nest has been described, also of the nominate race, from eastern Ecuador (Martin and Greeney 2006). This nest was built in an area where the canopy was composed almost entirely of 20 m-tall Alnus acuminata (Betulaceae) trees, with an understory of dense Chusquea bamboo interspersed with herbaceous Solanaceae, Urticaceae and Piperaceae. Specifically, the nest was on the edge of a patch of Chusquea and surrounded by more open herbaceous understory. This nest was 2 m above the ground and built onto a (presumably) naturally occurring clump of leaves and small branches which had accumulated on 8–10 criss-crossing, horizontal Chusquea branches.
This nest (Martin and Greeney 2006) was described in detail, and was composed primarily of sticks and twigs, with additional bamboo leaves, sparse moss, leaf petioles and a few dicot leaves mixed together to form the outer cup. The egg cup had a sparse lining of dark rootlets. Externally, the diameter was 27.0 x 27.0 cm (measured at perpendicular angles), and internally the cup which held the eggs was 11.5 x 11.5 cm in diameter and 7 cm deep. Externally, the nest was 18.5 cm tall. Overall, the nest described by Martin and Greeney (2006) was similar in structure and composition nests described for the closely related Watkins’s Antpitta (G. watkinsi) (Martin and Dobbs 2004, Greeney et al. 2009).

Eggs. Descriptions of the eggs of Chestnut-crowned Antpitta are all remarkably consistent and it appears that this species lays unmarked, sky blue to blue green eggs throughout its range. The three eggs collected by S. B. Gabaldon (American Museum of Natural History 13865), which were described as "buffy eggs with rufous blotches" by Wiedenfeld (1982), is clearly in error. Eggs have been described in the literature for three of the seven subspecies of Chestnut-crowned Antpitta:

ruficapilla – Oates and Reid (1903) give the measurements of both eggs collected by T. K. Solomon and described by Sclater and Salvin (1879): 30.0 x 25.4 and 31.0 x 26.2 mm. Schönwetter (1979) provides a mean of 30.6 x 25.6 mm for three eggs from an unspecified locality. Martin and Greeney (2006) measured two eggs of this subspecies in northeastern Ecuador: 28.5 x 24.3 and 29.9 x 24.2 mm. Previously unpublished measurements of three eggs from Azuay Province, Ecuador (Greeney) are: 31.3 x 25.0, 29.7 x 24.5, and 30.5 x 25.7 mm.

albilora – Taczanowski (1880) gives the measurments of three eggs from Cundinamarca, Peru: 29.0 x 24.0, 29.0 x 25.0, and 30.6 x 25.2 mm.

Nest with complete clutch of two, immaculate pale-blue eggs of Chestnut-crowned Antpitta. SierrAzul, Napo, Ecuador. 20 September 2004. © Harold F. Greeney

nigrolineata – Nehrkorn (1899, 1910) published two measurements for eggs of this subspecies: 30.0 x 25.0 and 27.0 x 24.0 mm. Schönwetter gives the mean measurement of three eggs as 28.4 x 24.4 mm.

These 18 egg measurements provide a mean of 29.4 ± 1.3 by 24.6 ± 0.6 mm for the eggs of Chestnut-crowned Antpitta. Surprisingly, despite this relatively high sample size of measured eggs (for an antpitta), only two of these published sources explicitly provide a clutch size (both 2 eggs) (Sclater and Salvin 1879, Martin and Greeney 2006). The addition of three unpublished observations of two egg clutches from eastern Ecuador (Greeney) suggests that two eggs are the normal clutch for this species (n = 5 clutches).

Nestling. Chestnut-crowned Antpittas are born with pink skin and long, whispy tufts of pale gray down on the head, back, and wings, but develop a dense covering of non-natal down by the time primary pin-feathers break their sheaths (Greeney 2013).Newly hatched nestlings of Chestnut-crowned Antpitta. SierrAzul, Napo, Ecuador. © Harold F. Greeney Like other species of antpittas, the young have bright orange rictal flanges, and striking crimson-orange mouth linings (Greeney et al. 2008). Nest with complete clutch of two, immaculate pale-blue eggs (stained with eclosion fluids) of Chestnut-crowned Antpitta. Yungilla, Azuay, Ecuador. 11 March 2005. © Harold F. Greeney

General breeding behavior. The behavior of Chestnut-crowned Antpittas while nesting has not been studied in detail. Both sexes participate in incubation and nestling-feeding duties (Martin and Greeney 2006), and it is presumed that both adults help to construct the nest, as in other Grallaria (Greeney et al. 2008).

Populations and Demography

There is no information related to topics such as age at first breeding, life span and survivorship, dispersal, or population regulation for Chestnut-crowned Antpitta.

Recommended Citation

Greeney, Harold F., and Guy M. Kirwan. 2013. Chestnut-crowned Antpitta (Grallaria ruficapilla), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=403241