Justification of Red List category
This species has a very small and declining single wild population tied to the mangroves of western Madagascar, which are suffering ongoing degradation. With further impacts suspected from hunting in parts of the range, this distinctive duck is assessed as Endangered and requires further safeguarding of mangrove habitat on Madagascar to prevent its loss from the wild.
The total population is estimated at between 630-1,900 mature individuals, based on an assessment of survey data at key sites (R. Rabarisoa in litt. 2022) and the area of suitable mangrove habitat within the range (Bunting et al. 2018). This value is similar to the population size in 2002, thought to be 1,500-2,500 individuals (H.G. Young in litt. 2002) roughly equivalent to 1,000-1,700 mature individuals. Survey information from ASITY Madagascar (R. Rabarisoa in litt. 2022) supplied maximum counts for the sites targeted for survey for the species, and additional counts for other important sites. For the Mahavavy Kinkony Wetland Complex (surveyed between 2004 and 2019) the maximum count was 353 (in 2011), while for Mangoky Ihotry Wetland Complex (2005 to 2019) the maximum was 110 in 2005, with a population of between 400-450 individuals present regularly between these two major sites (R. Rabarisoa in litt. 2022). Additional sites surveyed were Mahajamba (mangroves and estuaries) with a maximum count of 319 individuals in 2018; Besalampy (mangroves), 116 individuals in 2018; Riv Loza (mangroves), 32 individuals in 2020 and Baie de Bombetoka (mangrove), 30 individuals in 2021. The summed total of the maximum counts is 897-960. These sites are considered likely to support most of the population and include more than 50% of the extent of mangrove in patches that are larger than just channel-side vegetation (based on the mapped extent of mangroves from Global Mangrove Watch v2.0, Bunting et al. ). As such, a reasonable assumption would be to assume the total population size is no greater than double this value. The maximum population size would be that based on the assumption that these surveys recorded only mature individuals, hence 1,794-1,920 mature individuals as a range for the maximum population size, rounded to 1,800-1,900 mature individuals. A more precautionary assumption would be to use a standard proportion of two-thirds of the sampled population were mature individuals, giving an upper range of 1,200-1,270 mature individuals. Considering the minimum bound, there are individuals at several more mangrove areas, but a minimum number for these is uncertain. Hence to encompass all likely values, the minimum bound is set as the maximum counted number, rounded to 950 individuals hence equivalent to 630 mature individuals.
This species' population is inferred to be decreasing overall in line with extensive habitat loss and disturbance throughout its breeding range, exacerbated by hunting at both breeding and moulting sites. At monitored sites, numbers have not shown a rapid reduction over the past 25 years, although this may in part be due to the immigration of individuals from disturbed areas (Razafindrajao et al. 2017). Between 1950-1994, 60% of wetlands were lost across Madagascar (Kull 2012), equating to a rate of loss of 16% over three generations. Razafindrajao et al. (2017) states that the non-protected habitat is being cleared rapidly, and this species may be impacted by hunting. A greater proportion of the mangrove habitat is now protected hence it may be the case that current and future overall rates of wetland habitat loss within the range are lower. In addition, the generation length of the species has been revised following the methods of Bird et al. (2020) resulting in a reduction in the period over which a reduction is calculated. The population is now suspected to be declining at a moderate rate of 10-25% over three generations based on the recorded rate of past conversion (Kull 2012, Razafindrajao et al. 2017).
Anas bernieri is endemic to western Madagascar. Its range encompasses a narrow coastal strip along the whole of the west coast and the extreme north-east (Langrand 1995, F. Razafindrajao per R. Safford in litt. 1999, ZICOMA 1999, Young 2011). Sites of major importance to the species are concentrated in the central west to north west; the Mahavavy Kinkony Wetland Complex, Bembetoka River esturay and the Baie de la Mahajamba in Boeny region, numerous smaller sites in Menabe and Melaky regions on the central west coast (Young et al. 1993, Morris and Hawkins 1998, Razafindrajao et al. 2001, Carboneras and Kirwan 2020, Zöckler et al. 2021), with another key site in northern Atsimo-Andrefana: the Mangoky-Ihotry wetland complex (R. Rabarisoa in litt. 2022). The majority of the population is considered to fall within this area, with relatively few records from sites to the south and north, although a maximum count of 32 individuals was made at Loza Bay to the north in 2020 (R. Rabarisoa in litt. 2022).
Behaviour Birds breed during the wet season months of December to March (Kear 2005, Joiner et al. 2006, Young 2011), and moult at select, secure sites at the beginning of the dry season when they become flightless for a period (Razafindrajao 2000, Young 2006, Razafindrajao et al. 2012). They then move short distances to coastal areas in search of suitable habitat for the dry season (Kear 2005, Young 2006). During the breeding season the species occurs in solitary, dispersed pairs, but during the non-breeding season it is more gregarious and occurs in loose groups of up to 40 individuals (Green et al. 1994, Scott and Rose 1996). Pair-bonds may last through consecutive seasons and investment by males is high and involves the protection of the female and young (Young 2006). Habitat Breeding The species breeds only in seasonally flooded, non-tidal areas dominated by Black Mangrove Avicennia marina, on the landward side of littoral forest (Razafindrajao 2000, Joiner et al. 2006, Young 2006, H.G. Young in litt. 2007, Young 2011). Non-breeding During its post-breeding moult, during which time it is flightless (Young 2006), the species seeks out lakes that are rich in aquatic vegetation, and in the subsequent dry season it is found in coastal wetland areas of shallow water and nutrient-rich mud, including saline and brackish areas (Razafindrajao 2000, Kear 2005, Young 2011). Here it prefers open rather than vegetated wetlands (Young 2006) and is most often found in coastal mangrove forest, bays, estuaries and shallow saline wetlands just inland of mangroves (tannes), though it can also be found less frequently in marshes, dense deciduous forest, areas of open water and herbaceous savannah, especially where Hyparrhenia and Heteropogon grasses are present (Joiner et al. 2006). Diet Little is known about its diet except during moulting when it feeds on terrestrial and aquatic insects including Hymenoptera, Coleoptera, and Diptera, in addition to the seeds of various plant families and the leaves and stems of monocotyledons (Kear 2005). It usually feeds by dabbling in the mud while wading (Young 1995, Morris and Hawkins 1998). Breeding Site Nesting takes place in holes in Avicennia marina mangrove trees that have been created by storm damage or decay (Kear 2005, Joiner et al. 2006). Ducklings fledge at 45-49 days (Young 2006).
The species is impacted by extensive habitat loss, disturbance and potentially hunting. The distribution of known sites suggests that the single subpopulation may become fragmented as areas of habitat become unsuitable (Young 2006, H.G. Young in litt. 2007). The species has limited dispersal capabilities and isolation may result in the loss of genetic diversity (Young 2006). Furthermore it is threatened by virtue of being highly specific to a series of habitats - which are themselves threatened - throughout its annual cycle (Razafindrajao 2000). Conversion of shallow, muddy water-bodies to rice cultivation (Young et al. 1993) has been so widespread on the west coast that in the non-breeding season the species now appears to be confined to the few suitable wetlands that are too saline for rice-growing, i.e. some inland lakes and coastal areas such as estuaries and mudflats (Green et al. 1994, Young 2011). In 2004, during a dry-season survey in Menabe, this species was only found in saline wetlands (Young et al. 2014). Pressures on coastal wetlands are exacerbated by the movement of people from the High Plateau to coastal regions, which is driven by the exhaustion of land (Joiner et al. 2006). Mangroves are under increasing pressure from prawn-pond construction and timber extraction, which also leads to increased hunting as people enter the habitat (Morris and Hawkins 1998). Subsistence hunting during the nesting season and the trapping of moulting birds are also threats (Young 2006). It is considered a delicacy by hunters and was found in markets in Sofia in 2011 (H.G. Young in litt. 2012). In contrast, the breeding site at Ankazomborona is not threatened by aquaculture and there is little pressure from subsistence hunters, though there is some pressure from sport hunters (Razafindrajao et al. 2001). Breeding birds may suffer disturbance from human activity, such as the collection of crabs (Joiner et al. 2006). The species is potentially in competition for the use of suitable nest-holes with the Comb Duck Sarkidiornis melanotos, parrots Coracopsis species and nocturnal lemurs Lepilemur spp. and Cheirogaleus spp., though lemurs are absent in mangroves (Joiner et al. 2006, Young 2006).
Conservation Actions Underway
CITES Appendix II. It has been recorded from Baly Bay National Park, Tsimanampetsotsa Strict Reserve (ZICOMA 1999), Analabe Private Reserve, Kirindy Mitea National Park and Lac Bedo Ramsar Site (H.G. Young in litt. 2007, Young 2011). A captive-breeding programme started in 1993 (Morris and Hawkins 1998, Young 1998, 1999), and these birds are used to study breeding behaviour (Young 2006). The species is held in collections in Europe and North America and has an international studbook (H.G. Young in litt. 2016). Studies on the ecology of the wild birds (including possible provision of nest boxes; R. Lewis pers comm. 2001) and a conservation programme at Lac Antsamaka (in Manambolomaty Ramsar Site) have also been initiated. Flightless birds moulting wing feathers were caught and ringed annually in May and June at Antsamaky (Razafindrajao et al. 2012), but birds are no longer congregating there (H.G. Young in litt. 2012). Four new protected areas have been established, and will benefit this species, at Mahavavy-Kinkony, the Tsimembo Manambolomaty Complex, Menabe Antimena and the Mangoky-Ihotry complex (Razafindrajao et al. 2017). The proportion of protected habitat has now increased from 3% to 56% since 2011 (Razafindrajao et al. 2017).
40-45 cm. Small dabbling duck. Rather pale, warm greyish-brown all over, scalloped darker most conspicuously on flanks and breast, wing with black speculum. Head rather uniform, pale, pinkish-grey bill, slightly upturned. Similar spp. Told from all other ducks by lack of conspicuous head-pattern, bill colour, rather long neck, wide white borders to distinctive black speculum, and habit of feeding by wading in shallow muddy water. Hints Usually in pairs or small groups, feeding in mangroves, on lake edges or estuarine mudflats.
Text account compilers
Rotton, H., Martin, R., Clark, J.
Evans, M., Hawkins, F., Lewis, R., Pilgrim, J., Rabarisoa, R., Rabenandrasana, M., Razafindrajao, F., Réné De Roland, L.A., Safford, R., Shutes, S., Starkey, M., Symes, A., Taylor, J., Westrip, J.R.S., Young, G. & Zockler, C.
BirdLife International (2023) Species factsheet: Anas bernieri. Downloaded from http://datazone.birdlife.org/species/factsheet/madagascar-teal-anas-bernieri on 02/10/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 02/10/2023.