Amaurornis olivieri

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	GRUIFORMES	RALLIDAE

Scientific Name:

Amaurornis olivieri

Species Authority:

(Grandidier & Berlioz, 1929)

Common Name/s:

English	–	Olivier's Crake, Olivier's Rail, Sakalava Rail
French	–	Râle d'Olivier

Assessment Information [top]

Red List Category & Criteria:

Endangered C2a(i) ver 3.1

Year Published:

2008

Assessor/s:

BirdLife International

Reviewer/s:

Taylor, J., Butchart, S.

Contributor/s:

Rabenandrasana, M., Robertson, I., Safford, R., Hawkins, F., Taylor, P.

Justification:
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.

History:

2004	–	Endangered
2000	–	Critically Endangered
1996	–	Critically Endangered
1994	–	Critically Endangered

Geographic Range [top]

Range Description:	Amaurornis olivieri is known from several widely separated areas in lowland western Madagascar, and is rare and localised. Specimens were taken in 1930 and 1962⁴, and all records since have been field sightings: at Lake Bemamba a single bird seen in 1995³ and an adult in 1999⁵, two individual adults at Amboropotsy marsh (near Bekopaka) in 2001⁷, a pair with young and two other adults at Lac Ampandra (near Bejofo-Antanandava) in 2002⁸ and two adults (probably a pair) observed over several days at Lac Kinkony (south-west of Mahajanga) in 2003⁹. Surveys of potential sites in western Madagascan wetlands between the Betsiboka and Mangoky rivers from August 2003 to April 2004 found that the most important population is situated in northern areas in the Besalampy wetlands (Lakes Ampandra and Amarihy; 67 individuals recorded) and Lake Kinkony (12 individuals recorded)^11,12. Birds were not recorded at potential sites in the south¹², where they may be absent or populations may be close to extinction¹¹. Based on these survey results the population is not thought to exceed 250 individuals, and is estimated to number 100-200 birds¹¹. 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 population¹³.
Countries:	Native: Madagascar
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Survey results from 2003-2004 suggest that the population does not exceed 250 individuals, and is estimated to number 100-200 birds (M. Rabenandrasana in litt. 2004). 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.
Population Trend:	Decreasing

Population:

Survey results from 2003-2004 suggest that the population does not exceed 250 individuals, and is estimated to number 100-200 birds (M. Rabenandrasana in litt. 2004). 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.

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	Behaviour This species is not known to make any seasonal movements^4,14. Nesting has been observed in July¹⁵ and March¹, and juveniles have been found in December⁸ and in March¹⁴. Local knowledge suggests the species may be double-brooded⁸, or it may have a very extended breeding season stretching from July to March¹⁵. The majority of breeding observations between 2002-2006 occurred between the months of September and November¹⁵. 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 forages¹⁴. Water-lilies Nymphaea, appear to be particularly important^4,14, but it also uses floating Salvinia spp., sedges, grasses and the invasive water-hyacinth Eichhornia crassipes⁵. This also appears to be the habitat in which it breeds¹⁴. 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 floods⁸. In addition, during the dry season there is some evidence that it hides in dense beds of Phragmites⁸, and it has been recorded in bushes and grass emerging from the water in a clearing of a flooded palm-covered valley⁴. 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 vegetation⁹. Breeding site One nest was found 50cm above ground-level in Typha⁴, another in a deep tunnel of Phragmites, 70cm above the ground¹⁵. Clutch-size is probably two.
Systems:	Freshwater

Habitat and Ecology:

Behaviour This species is not known to make any seasonal movements^4,14. Nesting has been observed in July¹⁵ and March¹, and juveniles have been found in December⁸ and in March¹⁴. Local knowledge suggests the species may be double-brooded⁸, or it may have a very extended breeding season stretching from July to March¹⁵. The majority of breeding observations between 2002-2006 occurred between the months of September and November¹⁵. 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 forages¹⁴. Water-lilies Nymphaea, appear to be particularly important^4,14, but it also uses floating Salvinia spp., sedges, grasses and the invasive water-hyacinth Eichhornia crassipes⁵. This also appears to be the habitat in which it breeds¹⁴. 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 floods⁸. In addition, during the dry season there is some evidence that it hides in dense beds of Phragmites⁸, and it has been recorded in bushes and grass emerging from the water in a clearing of a flooded palm-covered valley⁴. 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 vegetation⁹. Breeding site One nest was found 50cm above ground-level in Typha⁴, another in a deep tunnel of Phragmites, 70cm above the ground¹⁵. Clutch-size is probably two.

Systems:

Freshwater

Threats [top]

Major Threat(s):	Wetland degradation is a cause of major concern for the species³. 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 cultivation¹², and by the impact of introduced fish⁴. 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 involved¹². Contrary to previous fears, the small size of this rail makes it an unlikely target for hunters⁸, and in some areas at least the species is taboo and the eggs not collected^8,9. 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 unchecked⁹. 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 Madagascar⁸.

Major Threat(s):

Wetland degradation is a cause of major concern for the species³. 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 cultivation¹², and by the impact of introduced fish⁴. 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 involved¹². Contrary to previous fears, the small size of this rail makes it an unlikely target for hunters⁸, and in some areas at least the species is taboo and the eggs not collected^8,9. 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 unchecked⁹. 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 Madagascar⁸.

Conservation Actions [top]

Conservation Actions:	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 River⁶. There are new initiatives underway and planned for the conservation of threatened wetlands such as the lower Mahavavy river area, including Lake Kinkony¹⁰. Surveys for the species were conducted in 2003-2004^11,12. Conservation Actions Proposed Continue surveys to find and census populations^5,11,12. Use GIS analysis to predict population size by extrapolating data into unsurveyed areas¹². 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^5,12. Initiate further wetland-conservation programmes, designed in cooperation with local communities, at its known locations¹⁰. Investigate the reasons for the loss of Phragmites¹². Establish a national conservation plan¹².

Conservation Actions:

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 River⁶. There are new initiatives underway and planned for the conservation of threatened wetlands such as the lower Mahavavy river area, including Lake Kinkony¹⁰. Surveys for the species were conducted in 2003-2004^11,12.

Conservation Actions Proposed
Continue surveys to find and census populations^5,11,12. Use GIS analysis to predict population size by extrapolating data into unsurveyed areas¹². 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^5,12. Initiate further wetland-conservation programmes, designed in cooperation with local communities, at its known locations¹⁰. Investigate the reasons for the loss of Phragmites¹². Establish a national conservation plan¹².

Citation:	BirdLife International 2008. Amaurornis olivieri. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 21 May 2012.
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