EN
Pale-headed Brush-finch Atlapetes pallidiceps



Justification

Justification of Red List Category
This species is listed as Endangered because its population is estimated at fewer than 250 mature individuals. The population has been increasing in numbers from 2003 to 2012 due to intensive conservation efforts and is stable since. Its status remains precarious, and continued conservation efforts will be vital if it is to survive and further improve. Future changes that constrain the level of conservation work implemented so far would risk a worsening in the species's status, in which case it would quickly become eligible for uplisting to Critically Endangered.

Population justification
Since 2009, 80-113 territories have been recorded in each year (D. Wege in litt. 2009; H. M. Schaefer in litt. 2020). The total population hence numbers 160-226 mature individuals. This is roughly equivalent to 240-340 individuals in total.

Trend justification
The number of occupied territories has been surveyed annually since 1999. 12-22 territories were counted in 1999, 15-27 territories in 2000, 35-37 territories in 2001, 20-35 territories in 2002, 30-34 territories in 2003, 42-45 territories in 2004, 50-52 territories in 2005, 59-61 territories in 2006 and 81-83 territories in 2007 (N. Krabbe in litt. 2007). In 2008, there were an estimated 110-120 occupied territories (M. Juiña in litt. 2008), and in 2009 the number of occupied territories was estimated at 113 (Krabbe et al. 2011). Counts of singing males found 99 in 2011, 107 in 2012 and 112 in 2013 (S. Hartmann in litt. 2014). In 2018 and 2019, 75 and 83 territories were counted respectively, albeit with lower observation effort as compared to previous years, so that the population is currently estimated at c.100 pairs (H. M. Schaefer in litt. 2020). An extremely rapid increase has occurred between 2003 and 2009, but the species has now reached carrying capacity within the Yunguilla Reserve (Hartmann et al. 2017; H. M. Schaefer in litt. 2020). Increases beyond the current population size are limited by habitat availability (H. M. Schaefer in litt. 2020).

Distribution and population

Atlapetes pallidiceps occurs in the río Jubones drainage, in Azuay and Loja, south Ecuador. There were no records between 1969 and 1998, when intensive studies found five pairs and two presumed immatures in two habitat patches in the Yunguilla Valley, near Girón, Azuay, and a further 1-2 pairs that were suspected to be supported by habitat in small ravines in the 1 km between the two patches (Agreda et al. 1999a, b). Despite repeated searches, it is unknown elsewhere within its presumed historical range (Agreda et al. 1999b).

Ecology

Its habitat is typical of regenerating landslides and fallow fields, with the species occurring at 1,650-1,950 m in the transition between arid and humid areas with dense low scrub, which is interspersed with small clearings and some patches of 2-3 m tall Chusquea bamboo (Agreda et al. 1999a, b; Schmidt and Schaefer 2003; Krabbe 2004). Birds feed on invertebrate prey, fruits and flowers during the rainy season, the rest of the year also taking a variety of fruit and seeds (Agreda et al. 1999a; Oppel et al. 2003; Krabbe 2004; H. M. Schaefer in litt. 2012; M. Juiña unpubl. data). The species often gleans prey from twigs of the composite bush Steiractinia sodiroi (Krabbe 2004). It is usually seen in pairs, mainly foraging on and within 2 m of the ground (Agreda et al. 1999a; Schmidt and Schaefer 2003; Krabbe 2004). Historical records are all from the edges of arid intermontane valleys, at 1,500-2,100 m (N. Krabbe in litt. 2012). Nests are placed within dense thickets of small bushes or bamboo (Schmidt and Schaefer 2003). A single clutch is raised every year, unsuccessful birds relaying (Oppel et al. 2003). Egg-laying takes place between late February and mid-April, with a few relaying as late as May, and young are fledged by late May (Oppel et al. 2003; N. Krabbe in litt. 2012; M. Juiña unpubl. data).

Threats

Brood parasitism by the Shiny Cowbird Molothrus bonariensis has a significant impact on breeding success (H. M. Schaefer and V. Schmidt in litt. 2002), with an overall parasitism rate of 42% in 2002 (Schmidt and Schaefer 2003; Oppel et al. 2004). The positive population trend observed in A. pallidiceps since the initiation of cowbird control in 2003 adds further weight to the significance of this threat (Krabbe et al. 2011). The species is susceptible to fires, which strongly reduce adult survival (Hartmann et al. 2015). The species is potentially threatened by droughts, as year-round availability of water was found to increase adult survival (Hartmann et al. 2015). An annual turnover of 40% in singing males, as calculated from data obtained in 1999-2007 (Krabbe et al. 2011), indicates that the impact of a change in management or a new threat would be rapid.

Conservation actions

Conservation Actions Underway
Management for this species has been extremely successful and very probably saved the species from extinction. The remaining 27 ha of suitable habitat, where it was observed in 1998, was purchased in 1999 and securely fenced off to remove grazing pressure (Sornoza Molina 2000; N. Krabbe in litt. 2012). The control of cowbirds between 2003 and 2011 as well as habitat management were crucial in the recovery of the species (Hartmann et al. 2017). A habitat management scheme was implemented in November 2002, in order to halt vegetation succession and create suitable habitat by selective thinning of dense thickets. This has mostly been successful, although some succession has occurred and at least one territory has been lost (H. M. Schaefer in litt. 2012). A habitat occupancy monitoring scheme was set up in 2004 to assess the success of this habitat management (Schmidt and Schaefer 2003). The reserve now encompasses 200 ha and holds over 95% of the known territories (H. M. Schaefer in litt. 2012). A second, satellite reserve has been established in an adjacent valley and the first territories have been recorded there (H. M. Schaefer in litt. 2020). Recent studies have investigated the species's breeding ecology, habitat use, population genetics and demography, and evaluated the conservation activities that led to the population recovery (H. M. Schaefer and V. Schmidt in litt. 2002; Schmidt and Schaefer 2003; Hartmann et al. 2014, 2015, 2017).

Conservation Actions Proposed
Maintain habitat through selective cutting in the non-breeding season (N. Krabbe in litt. 2012). If needed, reactivate the control of Shiny Cowbird, concentrating on the peak laying period of mid-February to mid-April (Krabbe et al. 2011; H. M. Schaefer in litt. 2020). Establish environmental education programmes around the known site.

Identification

16 cm. Pale grey-and-white passerine. Pale brownish-grey upperparts, old males have nearly white head, females and younger males more dingy head, with ill-defined buff stripes on crown sides and behind eye, and whitish underparts. Similar spp. Buff stripes on whitish head and lack of black hindcrown and nape separates this species from similar White-headed Brush-finch A. albiceps. Voice Song typical of genus, fairly high-pitched, 2-7 different phrases given at regular intervals of 7-14 s, virtually indistinguishable from song of White-winged Brush-finch. Interaction calls of the pair include a variety of fairly high-pitched notes by the male, and a low-pitched trill by the female. Contact calls very high-pitched.

Acknowledgements

Text account compilers
Hermes, C.

Contributors
Bird, J., Capper, D., Harding, M., Hartmann, S.H., Isherwood, I., Juiña, M., Krabbe, N., Pople, R., Schaefer, H.M., Schmidt, V., Sharpe, C.J., Stuart, T., Symes, A., Taylor, J., Temple, H. & Wege, D.


Recommended citation
BirdLife International (2022) Species factsheet: Atlapetes pallidiceps. Downloaded from http://www.birdlife.org on 01/10/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 01/10/2022.