Justification of Red List Category
This species was known from very few locations within a very small range in which habitat loss and degradation are continuing, and therefore qualified as Endangered. However, a remapping of the species' range to incorporate new data has greatly increased the estimated Extent of Occurrence and population. Nevertheless, it still has a small range and population, and continues to suffer from habitat loss that is likely to be causing population declines. It is thus downlisted to Vulnerable.
The population is estimated to number 2,500-9,999 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.
A slow and ongoing population decline is suspected, owing to rates of habitat loss.
Grallaria milleri occurs in the Volcán Ruíz-Tolima massif of the Central Andes, Colombia, (Caldas, Risaralda, Quindío and Tolima). Ten specimens were collected in Caldas and Quindío between 1911 and 1942. It was next recorded in May 1994, in Ucumarí Regional Park, Risaralda (Kattan and Beltrán 1997). Surveys carried out in 1994-1997 caught and banded 11 birds, and estimated that 106 individuals were present in a 0.63 km2 area (Kattan and Beltrán 1997, Kattan and Beltrán 1999). Further observations have been made on the south-east slope of Volcán Tolima in the río Toche valley during 1998-2000, where it is considered uncommon and local (López-Lanús et al. 2000, B. López-Lanús in litt. 2000, P. G. W. Salaman in litt. 1999, 2000, Renjifo et al. 2002). In 1999 and 2000, it was also found in the río Blanco catchment (Caldas) and near Roncesvalles (Tolima) (Renjifo et al. 2002). A misidentified Grallaria specimen taken at Santa Elena, 8km east of Medellín, Antioquia in 1878 has provisionally been described as a new subspecies, G. m. gilesi (Salaman et al. 2009). Its type locality is 140 km north of the nearest occurrence of G. m. milleri and no longer appears to have habitat to support a population (Salaman et al. 2009). Recent surveys suggest the subspecies is likely to be extinct (P. G. W. Salaman in litt. 2011).
In Ucumarí, it has been recorded from three types of habitat: early secondary growth vegetation with a high density of herbs and shrubs; the understorey of 30-year-old alder (Alnus) plantations; and the understorey of 30-year-old secondary forest (Kattan and Beltrán 1997), with no significant difference in population density between the three. Primary forest in Ucumarí is inaccessible (Kattan and Beltrán 1999). The ten historical specimens were taken at 2,745-3,140 m and, in the Toche valley, it occurs at 1,800-2,600 m (López-Lanús et al. 2000, P. G. W. Salaman in litt. 1999, 2000). In Ucumarí, all records in 1994-1997 were in a narrow elevational band of 2,400-2,600 m (Kattan and Beltrán 1997, 1999). A radio-tracked individual in Ucumarí used a territory of 4.1 ha (Kattan and Beltrán 2002). Vocal activity apparently peaks in May-June in the Toche valley (P. G. W. Salaman in litt. 1999, 2000).
Most forest below 3,300 m in the Central Andes has long been converted to agricultural land-use. In the Toche valley, this has primarily taken place since the 1950s, mostly for coffee plantations, potatoes, beans and cattle-grazing (López-Lanús et al. 2000, P. G. W. Salaman in litt. 1999, 2000). Some forest clearance continues and mature secondary forest patches are now scattered. Natural vegetation cover is judged to have been reduced to c.15% between 1,900 and 3,200 m, with most remnants occurring above 2,200 m (López-Lanús et al. 2000, P. G. W. Salaman in litt. 1999, 2000). Searches for G. m. gilesi in remnant forests have so far failed, suggesting that this taxon may already be extinct (Salaman et al. 2009).
Conservation Actions Underway
This species is considered Endangered at the national level in Colombia (Renjifo et al. 2002, 2014). Significant numbers are well protected in Ucumarí Regional Park, Risaralda (Kattan and Beltrán 1997) and it is also found in the Río Blanco Nature Reserve (Kattan et al. 2014). There are several protected areas adjacent to Ucumarí, but it has not been recorded within them (Wege and Long 1995). In the Toche valley, it occurs in La Carbonera, a small private nature reserve (Renjifo et al. 2002).
18 cm. Medium to large antpitta with breast-band. Uniform dark brown with dingy white lores, throat and belly, forming broad, brown breast-band. Similar spp. Tawny Antpitta G. quitensis is ochraceous-buff below, with paler mottling and no breast-band. Voice Territorial and alarm call a loud, whistled wooee rising slightly. Infrequently-heard soft whistle puuh, pü-pü, with third note higher.
Text account compilers
Isherwood, I., Pople, R., Sharpe, C J, Stuart, T., Symes, A., Khwaja, N.
Molina-Martínez, Y., Cortés, O., Donegan, T., Salaman, P., López-Lanús, B.
BirdLife International (2021) Species factsheet: Grallaria milleri. Downloaded from http://www.birdlife.org on 16/01/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/01/2021.