|Scientific Name:||Amaurornis olivieri|
|Species Authority:||(Grandidier & Berlioz, 1929)|
|Red List Category & Criteria:||Endangered C2a(i) ver 3.1|
|Reviewer/s:||Butchart, S. & Taylor, J.|
|Contributor/s:||Hawkins, F., Rabenandrasana, M., Robertson, I., Safford, R. & Taylor, P.|
This species is listed as Endangered because the total population is likely to be very small and is severely fragmented. It is severely threatened by the widespread and rapid degradation and destruction of wetlands in Madagascar.
Amaurornis 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: Lacs Kinkony, Ampandra, Amparihy, Sahapy and 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 underestimation, 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).
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||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 underestimation 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 individuals. This equates to 375-1,499 individuals in total, rounded here to 350-1,500 individuals.|
|Habitat and Ecology:||
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 in 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 2002-2006 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 Lake Kinkony suggest the diet includes both crustaceans (found on the short sub-surface roots of Salvinia sp.) and invertebrates (spiders and insects) found on top of the floating vegetation (M. Rabenandrasana in litt. 2003). Breeding site One nest was found 50cm above ground-level in Typha (Taylor and van Perlo 1998), another in a deep tunnel of Phragmites, 70cm above the ground (Rabenandrasana 2007). Clutch-size is probably two.
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 to 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 lands 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(I. Robertson in litt. 2003, M. Rabenandrasana in litt. 2003). Rice cultivation impinges on its native habitat (such as at Lake 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).
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 Lake Bemamba, Lake 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 Lake 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). Conservation Actions Proposed
Continue surveys to find and census populations(P.B. Taylor in litt. 1999, M. Rabenandrasana in litt. 2004, Rabenandrasana and Sama 2006). Use GIS analysis to predict population size by extrapolating data into unsurveyed areas (Rabenandrasana and Sama 2006). Investigate its ecology, especially its population ecology, year-round (in at least one site, e.g. Lake Bemamba, Lake Kinkony and Lake Ampandra) to identify the causes of its rarity (P.B. Taylor in litt. 1999, Rabenandrasana and Sama 2006). Initiate further wetland-conservation programmes, designed in cooperation with local communities, at its known locations (R. Safford in litt. 2003). Carry out anti-erosion management in the most vulnerable water catchment areas, and attempt to restore the most severely degraded marshes (Andriamasimanana and Rabarimanana 2011). Establish a national conservation plan (Rabenandrasana and Sama 2006). Seek full protection of known sites as soon as possible, by including them in priority-setting for short- and medium-term conservation action under the Malagasy Government’s new Protected Area System expansion policy (Rabenandrasana et al. 2009). Conduct public awareness-raising programmes with the aim of reducing persecution and disturbance, particularly during the breeding season (Rabenandrasana et al. 2009).
|Citation:||BirdLife International 2012. Amaurornis olivieri. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 25 May 2013.|
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