Data Zone
Justification of Red List category
This species is listed as Endangered because the total population is estimated to be small and experiencing a continuing decline due to the widespread degradation and destruction of wetlands in Madagascar.
Population justification
Survey results from 2003-2006 estimated a total of 215 individuals at five key sites, suggesting that the total population may not exceed 250 individuals (M. Rabenandrasana in litt. 2004; Rabenandrasana et al. 2009). However, this may be an underestimate as the surveys were brief and the methods were still being developed, thus the species is not necessarily absent at sites where it was not recorded, and the number of sightings is likely to indicate a larger population (R. Safford in litt. 2004). Therefore, the estimated population range used here is 250-999 mature individuals. The largest single population recorded so far is only 62 individuals (Rabenandrasana et al. 2009).
Trend justification
The species is inferred to be in decline owing to the continuing degradation and conversion of wetlands in Madagascar for cultivation (Kull 2012; D'Urban Jackson et al. 2019). Kull (2012) estimated that between 1950-1994, 60% of wetlands were lost, roughly equating to a loss rate of 21% over three generations (11.4 years [Bird et al. 2020]). As wetland degradation is linked to the expanding human population, it is expected that the declines will continue into the future, and the rate of population decline for this species is suspected to fall into the band 20-29%.
Zapornia olivieri is known from several widely separated areas in lowland western Madagascar, and is rare and localised. Specimens were taken in 1930 and 1962 (Taylor and van Perlo 1998), and all records since have been field sightings: at Lake Bemamba a single bird seen in 1995 (Ramanampamonjy 1995) and an adult in 1999 (P. B. Taylor in litt. 1999); two individual adults at Amboropotsy Marsh (near Bekopaka) in 2001 (Willard and Goodman 2002); a pair with young and two other adults at Lac Ampandra (near Bejofo-Antanandava) in 2002 (I. Robertson in litt. 2003), and two adults (probably a pair) observed over several days at Lac Kinkony (south-west of Mahajanga) in 2003 (M. Rabenandrasana in litt. 2003). Surveys of potential sites in western Madagascan wetlands between the Betsiboka and Mangoky rivers from August 2003 to November 2006 found the species at five sites: Lac Kinkony, Lac Ampandra, Lac Amparihy, Lac Sahapy and Lac Mandrozo (Rabenandrasana et al. 2009). At each site the population was small (12–39 individuals, maximum count of 39 at Lac Amparihy) and the highest density was 20 individuals per km2; the total number of birds recorded was 100 and the population at the five sites was estimated at 215 individuals (Rabenandrasana et al. 2009). Birds were not recorded at potential sites in the south (Rabenandrasana and Sama 2006), where they may be absent or populations may be close to extinction (M. Rabenandrasana in litt. 2004). Based on these survey results the population may not exceed 250 individuals. This may be an underestimate, however, as the surveys were brief and the methods were still being developed, thus the species is not necessarily absent at sites where it was not recorded, and the number of sightings is likely to indicate a larger population (R. Safford in litt. 2004).
Behaviour This species is not known to make any seasonal movements (del Hoyo et al. 1996; Taylor and van Perlo 1998). Nesting has been observed in July (Rabenandrasana 2007) and March (Langrand 1990), and juveniles have been found in December (I. Robertson in litt. 2003) and March (del Hoyo et al. 1996). Local knowledge suggests the species may be double-brooded (I. Robertson in litt. 2003), or it may have a very extended breeding season stretching from July to March (Rabenandrasana 2007). The majority of breeding observations between 2002 and 2006 occurred between the months of September and November (Rabenandrasana 2007).
Habitat The species has been found in areas of dense, high, marginal vegetation in streams, lakes and marshes. It prefers gaps (e.g. pirogue channels) between high Phragmites, Typha and Cyperus beds where open water occurs with patches of short, mixed floating vegetation on which it forages (del Hoyo et al. 1996). Water-lilies Nymphaea appear to be particularly important (del Hoyo et al. 1996; Taylor and van Perlo 1998), but it also uses floating Salvinia spp., sedges, grasses and the invasive water-hyacinth Eichhornia crassipes (P. B. Taylor in litt. 1999). This also appears to be the habitat in which it breeds (del Hoyo et al. 1996). The species may have been under-recorded in the past because it is very difficult to observe from the shore, since the hidden alcoves of floating vegetation that it frequents are difficult to access during the wet-season floods (I. Robertson in litt. 2003). In addition, during the dry season there is some evidence that it hides in dense beds of Phragmites (I. Robertson in litt. 2003), and it has been recorded in bushes and grass emerging from the water in a clearing of a flooded palm-covered valley (Taylor and van Perlo 1998).
Diet Field observations at Lac Kinkony suggest the diet includes both crustaceans (found on the short sub-surface roots of Salvinia spp.) and invertebrates (spiders and insects) found on top of the floating vegetation (M. Rabenandrasana in litt. 2003).
Breeding site One nest was found 50 cm above ground-level in Typha (Taylor and van Perlo 1998), another in a deep tunnel of Phragmites, 70 cm above the ground (Rabenandrasana 2007). Clutch size is 2-3 (Rabenandrasana et al. 2009; Pruvot et al. 2018). Both males and females were observed incubating the nest, which was constructed in a dense mat of Phragmites mauritianus. Incubation lasted for 15-17 days, and juveniles were independent of their parents after 45 days (Pruvot et al. 2018).
Wetland degradation is a cause of major concern for the species (Ramanampamonjy 1995). Like the threatened Madagascar Grebe Tachybaptus pelzelnii, it has probably been affected by the loss of fringing water-lily habitat, following the conversion of wetlands for rice cultivation (Rabenandrasana and Sama 2006), and by the impact of introduced fish (Taylor and van Perlo 1998). The species is also threatened by a reduction in the area of Phragmites, which may be due in part to cutting for human use, although this is not well understood and other factors may be involved (Rabenandrasana and Sama 2006). Lac Kinkony is highly threatened by the conversion of adjacent unprotected land into rice paddies, and an estimated 80% of historical reed area had been lost by 2008, with increased turbidity associated with erosion the primary contributor to reed loss (Andriamasimanana and Rabarimanana 2011). Contrary to previous fears, the small size of this rail makes it an unlikely target for hunters, and in some areas at least the species is taboo and the eggs not collected ( M. Rabenandrasana in litt. 2003, I. Robertson in litt. 2003). Rice cultivation impinges on its native habitat (such as at Lac Kinkony), and the burning of marshland areas by farmers in the dry season also threatens the species, especially when these fires go unchecked (M. Rabenandrasana in litt. 2003). At the Befojo site, the local fishing industry centred on the lakes may make it less likely that the lakes will be drained for rice cultivation, as is happening to wetlands across Madagascar (I. Robertson in litt. 2003). Disturbance by fishermen and people from local villages may pose a threat, and the potential effects of other processes such as hydrological change or the effects of exotic fish or vegetation are uncertain (Rabenandrasana et al. 2009). Cyclones can be a natural threat, as they disturb the habitat and so the species has to use less favourable habitats, which may expose them to other threats such as dog predation and human disturbance (Rabenandrasana et al. 2009).
Conservation Actions Underway
The Malagasy government has ratified the Ramsar Convention, which came into force for the country in 1999 and may herald improved conservation measures for wetlands. Several wetland areas where the species occurs, or has occurred, are the subject of planned conservation measures, including Lac Bemamba, Lac Kinkony and the Mangoky River (ZICOMA 1999). There are new initiatives underway and planned for the conservation of threatened wetlands such as the lower Mahavavy River area, including Lac Kinkony (R. Safford in litt. 2003), and in 2007 the Mahavavy-Kinkony Reserve received temporary protected status, with the hope that permanent protection would follow. Surveys for the species were conducted in 2003-2006 (M. Rabenandrasana in litt. 2004; Rabenandrasana and Sama 2006; Rabenandrasana et al. 2009).
19 cm. Small, mostly blackish rail. Dark chestnut mantle, wing-coverts and upper scapulars, bright yellow bill and red legs. Similar spp. From all other Malagasy rails by yellow bill, lack of white on undertail, and dark chestnut mantle. From Common Moorhen Gallinula chloropus by small size, lack of white on flanks and red legs, and from Allen's Gallinule Porphyrula alleni by lack of bluish body coloration. Hints Extremely shy, runs rapidly to dense cover.
Text account compilers
Clark, J.
Contributors
Benstead, P., Ekstrom, J., Evans, M., Hawkins, F., Khwaja, N., Rabenandrasana, M., Robertson, I., Safford, R., Shutes, S., Starkey, M., Symes, A., Taylor, P.B., Taylor, J. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: Sakalava Rail Zapornia olivieri. Downloaded from
https://datazone.birdlife.org/species/factsheet/sakalava-rail-zapornia-olivieri on 24/11/2024.
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 24/11/2024.