VU
Appert's Tetraka Xanthomixis apperti



Justification

Justification of Red List Category
This species has a very small range, within which it is known from only 4 forest patches. It is therefore currently classified as Vulnerable, but evidence of a continuing decline in its population or range would result in its uplisting to Endangered. Conversely, it may prove to be more widely distributed and to occupy a continuous distribution between the known locations, in which case it may be appropriate to downlist to a lower threat category.

Population justification
The population size is preliminarily estimated to fall into the band 1,000-2,499 individuals. This equates to 667-1,666 mature individuals, rounded here to 600-1,700 mature individuals.

Trend justification
The species's population is suspected to be stable owing to the cessation of forest clearance in the Zombitse-Vohibasia National Park in 1994 (ZICOMA 1999) and the species's apparent resistance to low levels of forest degradation, at least (Mustoe et al. 2000).

Distribution and population

Bernieria apperti is a relatively recently discovered species with a very localised distribution in south-west Madagascar. It was known from only a limited number of possible sites: Zombitse-Vohibasia National Park (type locality) (found in both Zombitse and Vohibasia), Analavelona Classified Forest (where it is reported to be common), and recently at dry spiny forest at Salary Bay (ZICOMA 1999, Langrand and von Bechtolsheim 2009, Hawkins and Sartain 2013). During surveys of Zombitse-Vohibasia National Park in 1996 the species was considered common at Ambiamena and Andranamaitso and rare in Vohibasia Forest (Mustoe et al. 2000). It was not recorded during extensive ornithological surveys of the northern part of the Mikea Forest (Raherilalao et al. 2004) but may prove to be more widespread than currently thought.

Ecology

This species is found in family groups of 2-8, sometimes associating with flocks of P. madagascariensis (Langrand 1990). At Zombitse-Vohibasia it is found in the dense underbrush of undisturbed, dry, deciduous forest at about 600-800 m (Morris and Hawkins 1998). Analavelona is a tract of relict evergreen forest on an isolated massif at about 1,300 m (ZICOMA 1999). The species feeds on small invertebrates gleaned from the leaves and branches of low shrubs and on the ground (Langrand 1990, Morris and Hawkins 1998). Observations suggest that the species tolerates low levels of selective exploitation (Mustoe et al. 2000). The sightings at Salary Bay in 2009 were made in low altitude coastal dry spiny forest thicket, raising the possiblity that the species is either a resident with a broader habitat tolerance than previously known, or possibly that it undertakes localised altitudinal movements (Langrand and von Bechtolsheim 2009).

Threats

Forest clearance for maize and manioc and some charcoal production (Mustoe et al. 2000) is the main threat to this species although, owing to conservation efforts, there has been no new clearance at Zombitse-Vohibasia since 1994 (ZICOMA 1999). Parts of the national park have been heavily selectively logged in the past and some areas of forest are exploited for building materials and used for cattle-grazing (Mustoe et al. 2000). Burning is carried out in some open areas to encourage grass regeneration for grazing, and there is a danger of fire spreading to nearby areas of degraded forest. If fires penetrate and destroy gallery woodland such areas would be at risk of losing surface water and consequently could experience desertification. During surveys in the Zombitse-Vohibasia National Park in 1996, it was noted that the species was encounted most frequently in an area that had a recent history of intensive selective logging, perhaps indicating that it benefits from such habitat alteration, at least temporarily (Mustoe et al. 2000). Analavelona is not managed as a protected area, but is relatively isolated, and forest clearance is not thought currently to present a threat. This species may be vulnerable to climate change (R. Andriamasimanana in litt. 2016).

Conservation actions

Conservation Actions Underway
Zombitse-Vohibasia Forest has been gazetted as a National Park (Morris and Hawkins 1998). Analavelona is unprotected but may be included in the activities of the WWF Zombitse-Vohibasia Conservation Project in the future (ZICOMA 1999).

Conservation Actions Proposed
Conduct studies to estimate its population size (ZICOMA 1999). Carry out surveys for the species at Upper Mangoky and Ankazohabo Forests (M. Rabenandrasana in litt. 2007). Design and carry out regular surveys to monitor population trends (starting in Zombitse Forest near Andranamaitso, perhaps as a responsibility of the park guards, who should receive survey training) (Mustoe et al. 2000). Study the impact of moderate to high levels of forest exploitation on the species (Mustoe et al. 2000). Monitor rates of forest clearance and degradation within its range. Target conservation efforts on Ambiamena Forest (Mustoe et al. 2000). Promote ecotourism and use revenues to fund surveys (Mustoe et al. 2000). Regularly liaise with the more isolated communities in the Zombitse-Vohibasia National Park to help reconcile their needs and aspirations with conservation efforts (Mustoe et al. 2000). Carry out surveys to determine whether it has a largely continuous distribution between Zombitse-Vohibasia-Isoky, Analavelona, and Salary Bay, and study birds at these sites at different seasons (including genetic analysis and/or banding) to determine whether there are seasonal movements between sites or whether they are isolated subpopulations (Langrand and von Bechtolsheim 2009).

Identification

15 cm. Small, mainly terrestrial babbler-like bird. Greenish upperparts, with darker flight feathers and tail. Greyish crown, nape and rear ear-coverts, with short dull off-white supercilium. Whitish throat, and variably-washed peachy-orange breast and upper belly. Whitish lower belly and vent. Pale pink bill with darker culmen, pale pinkish-grey legs. Similar spp. Differs from Long-billed Greenbul B. madagascariensis by smaller size, grey head, white throat, slimmer and shorter bill.

Acknowledgements

Text account compilers
Ekstrom, J., Evans, M., Shutes, S., Starkey, M., Symes, A., Taylor, J. & Westrip, J.

Contributors
Hawkins, F., Langrand, O., Rabenandrasana, M. & Andriamasimanana, R.


Recommended citation
BirdLife International (2020) Species factsheet: Xanthomixis apperti. Downloaded from http://www.birdlife.org on 09/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 09/08/2020.