• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This species qualifies as Vulnerable because its population is declining owing to the destruction and degradation of its forest habitat, and this decline is likely to become rapid in the near future and over the next three generations.

Population justification
The species can be easily overlooked, and a study on Masoala Peninsula estimated a density of 4 territories per km², which would equate to a maximum of approximately 8,800 pairs in the peninsula alone (Thorstrom and Lind 1999). Knowing this, but considering the species' high specialisation in undisturbed damp forest, and continuing habitat loss, deterioration and fragmentation, and the detrimental effect of the latter on the occurrence of the species (Benjara et al. 2021), a conservative measure of 10-25% occupancy of the range (approximately 48,900 km²) at a precautionary 1 territory per km², can be assumed. This results in a total estimate of 4,900-12,200 pairs, or approximately 9,800-24,500 mature individuals, and the species' population size is therefore placed in a rounded band of 10,000-25,000 mature individuals.

Trend justification
The species is highly dependent on primary, undisturbed forest, and is considered absent from degraded forest, and forest with a majority of secondary growth (Woog et al. 2006, Langrand and Kirwan 2020). Studies have found that it does not occur in habitats that have been sufficiently degraded, does not occur in patches within the forest that have been cleared for small-scale agriculture (Woog et al. 2006, Rocha et al. 2015), and does not occur in medium to small forest fragments (Rakotoarisoa and Capparella 2013). 
Loss of tree cover within the species' range (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein) over the past three generations, due primarily to clearance for subsistence cultivation, human pressure and commercial logging (Jenkins 1987, Stattersfield et al. 1998, ZICOMA 1999), has been estimated at approximately 25%, and suspected to accelerate to a rate of approximately 31% between 2016 and 2031. Based on a rate of decline of approximately 2% over the past five years, and the continuing threats to this habitat, it is therefore suspected that the loss of forest habitat within the species' range will continue at a rate of approximately 31% over the next three generations.
Considering the species' high dependence on forest habitats, and sensitivity to its degradation and reduction in size, combined with the ongoing forest loss within its range, the current population size is therefore inferred to be undergoing a continuing declining due to the loss of suitable key habitats and increase in forest edge. It is suspected that the species' rate of decline in population size is in line with the rate of forest loss.

Brachypteracias leptosomus is considered fairly common within its restricted habitat of low- and mid-altitude primary forests in eastern Madagascar, from Daraina Forest in the north to Andohahela in the south (Langrand 1990).

This secretive species is found solely in undisturbed, humid, primary rainforest (Langrand and Kirwan 2020). It is a low- to mid-altitude specialist (Hawkins 1999). At the upper part of its altitudinal range it occurs only where trees are large (Evans et al. 1992, ZICOMA 1999). It prefers forest with dark, humid areas, a moderate ground cover of herbaceous, mossy vegetation, and deep leaf-litter (Thorstrom and Lind 1999, Langrand and Kirwan 2020). The least terrestrial of the rainforest ground-roller species, it spends much time perched 2-15 m above ground on horizontal branches, searching for prey (Langrand 1990, Evans et al. 1992). It feeds on invertebrates (88%), often terrestrial, and also small vertebrates (reptiles and amphibians, 12%) (Langrand and Kirwan 2020). It nests in tree cavities and the root masses of epiphytes, often around 20 m above the ground (Thorstrom and Lind 1999). The home range of one pair was 19 ha, occurring over an altitudinal range of 5-200 m within that 19 ha; pairs occupied contiguous territories in this undisturbed habitat (Thorstrom and Lind 1999). The species appears able to re-nest rapidly after natural nest failure (Thorstrom and Lind 1999).

The principal threat to its forest habitat is from slash-and-burn cultivation by subsistence farmers, which results in progressively more degraded regrowth and leads eventually to bracken-covered areas, grassland or other non-forest vegetation (Stattersfield et al. 1998). Much of the forest on the eastern coastal plain has either already been cleared or is highly degraded, remaining habitat is under pressure from the increasing human population and commercial logging is an additional threat in some areas (Jenkins 1987, ZICOMA 1999). The species is likely to also be affected by habitat fragmentation, as are other similarly forest-dependent species (Benjara et al. 2021). Climate change may also threaten its ecological niche (Andriamasimanana and Cameron 2013). If present trends continue, the remaining unprotected forest, especially at the lower altitudes preferred by this species, will disappear within decades (Stattersfield et al. 1998). The species is also hunted (ZICOMA 1999).

Conservation Actions Underway
The species occurs in 23 Important Bird Areas (77% of the total in eastern Malagasy forest) and is found in nine National Parks, two Strict Reserves, three Special Reserves and six Classified Forests (ZICOMA 1999).

Conservation Actions Proposed
Carry out surveys across the species' range in order to produce an improved estimate of the population size based on more recent and complete survey data. Pursue further ecological studies to determine its home-range size and its dispersal capability across deforested, disturbed and degraded areas, in order to clarify the impact of forest fragmentation on its population structure. Compare survey data collected from protected and unprotected areas (M. Rabenandrasana in litt. 2007). Conduct research into the level of hunting pressure on the species. Conduct regular surveys to monitor population trends. Monitor rates of habitat loss and degradation. Improve the management of the eastern humid forests, especially the control of fires used in slash-and-burn cultivation.

38 cm. Thickset, arboreal bird with large head and strong bill. Upperparts mid green-brown, with purple iridescence on rear crown and nape, and fine white tips to wing-coverts. Pale supercilium is short, steeply curved. Tail is fairly long, with white tips to the outer feathers. Underparts are paler, with brown throat and ear-coverts overlain with white spots, below which is a wide, white crescentic breast-band. Lower breast and belly are barred darker brown. Similar spp. Combination of purple nape, solid dark grey bill, white breast-band and white-tipped tail eliminate White-browed Owl Athene superciliaris, the only bird which remotely resembles this species. Voice Call is a long series of bop notes, often given in early morning or evening, at a rate of about one a second. Hints Perches for long periods almost immobile.

Text account compilers
Rutherford, C.A.

Contributors
Hawkins, F., Rabenandrasana, M., Thorstrom, R., Safford, R., Symes, A. & Westrip, J.R.S.

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Recommended citation
BirdLife International (2024) Species factsheet: Short-legged Ground-roller Brachypteracias leptosomus. Downloaded from https://datazone.birdlife.org/species/factsheet/short-legged-ground-roller-brachypteracias-leptosomus on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.