Justification of Red List Category
This species is listed as Endangered because it is believed to have a very small, although widely dispersed, population, all in one subpopulation, which is undergoing a continuing decline owing to intensive hunting, habitat loss and degradation, and disturbance.
The population is estimated to number 2,000-5,000 individuals, roughly equating to 1,300-3,300 mature individuals (H. G. Young in litt. to Durrell Wildlife Madagascar Project 2002, via Wetlands International 2021).
While the population at the protected area of Lake Alaotra appears to be stable (Razafindrajao et al. 2017), the population overall is inferred to be declining owing to habitat loss and hunting. Kull (2012) estimated that between 1950-1994, 60% of wetlands were lost, roughly equating to a loss rate of 22% over 12 years (three generations [Bird et al. 2020]). As this species is also subject to intensive hunting, and is intolerant of human disturbance (H. G. Young in litt. 2012), the overall rate of decline is suspected to fall in the band 30-49%. As wetland habitats are lost to agriculture (Kull 2012), and both agricultural expansion and hunting pressure are linked to the expanding human population, these rates are suspected to continue into the future.
Anas melleri is endemic to Madagascar, where it is found on the eastern and northern high plateau, in eastern drainage patterns (H. G. Young in litt. 2007, Young 2013). There are populations on isolated massifs on the western edges of the plateau (H. G. Young in litt. 2007). Records from the west (B. Hughes in litt. 1998, Stattersfield et al. 1998) below the plateau (H.G. Young in litt. 2007), probably refer to vagrant or wandering birds (ZICOMA 1999). An introduced population on Mauritius is probably now extinct (H. G. Young in litt. 2012). Although previously described as common in many areas of Madagascar (apparently with little supporting evidence; H. G. Young in litt. 2007), there has been a widespread decline since human colonisation, which has continued unabated over the last 20 years (Langrand 1990). It is probably no longer common anywhere, except perhaps in forested areas of the northwest and in the wetlands around Lake Alaotra where there are some breeding pairs, but where many non-breeders collect (H. G. Young in litt. 2007), with up to 500 birds present (Morris and Hawkins 1998; ZICOMA 1999) (but see Randriamahefasoa 2001). All birds seem to be within a single subpopulation (Scott and Rose 1996, B. Hughes in litt. 1998), which is probably continuing to decline rapidly (Young and Rhymer 1998).
Behaviour This species is largely sedentary, although there exist some records from the west coast where it does not usually occur, suggesting that it may wander to some degree within Madagascar (Ellis-Joseph et al. 1992, Morris and Hawkins 1998, Young 2013). Nesting usually takes place during the months of September-April (Langrand 1990, Scott and Rose 1996), with the exact timing thought to be dependent upon levels of rainfall (Kear 2005). It has been recorded to breed as early as July (Kear 2005). During the breeding season it usually occurs in pairs, and is highly territorial and aggressive, particularly towards conspecifics (H. G. Young in litt. 2007, 2012, Young 2013), with pairs defending territories of up to 2 km in length ( H. G. Young in litt. 2007, Young 2013). Non-breeding birds often congregate in small groups (Kear 2005), or occasionally in large numbers, with flocks of over 200 birds recorded at Lake Alaotra (Langrand 1990; Scott and Rose 1996; Kear 2005).
Habitat This species occurs in inland freshwater wetland (Young and Rhymer 1998) habitats from sea-level to 2,000 m (del Hoyo et al. 1992). It is most often found in small streams that run east off the high plateau (H. G. Young in litt. 2007, Young 2013), but also inhabits lakes, rivers, woodland ponds and marshes, especially in humid forested areas (Langrand 1990, Scott and Rose 1996, Stattersfield et al. 1998, H. G. Young in litt. 2007). It is sometimes found in rice-fields (del Hoyo et al. 1992). It favours slow-moving water but will inhabit faster-moving streams and rivers when the preferred habitat is not available (del Hoyo et al. 1992, Kear 2005). It rarely inhabits coastal regions, but has been recorded at the Pangalanes Canal (Young 2013). Breeding It especially breeds along small streams and backwaters around lakes (Young et al. 2000), and also probably along undisturbed rivers (Pidgeon 1996, Young et al. 2000).
Diet This species forages mainly by dabbling ( Kear 2005, H. G. Young in litt. 2007), but may also forage on land (Kear 2005). Its diet includes aquatic seeds and plants (Langrand 1990, H. G. Young in litt. 2007) as well as invertebrates, particularly molluscs (Kear 2005). In captivity small fish, chironomid flies, filamentous algae and grasses are also eaten (Kear 2005). Its presence in rice-fields suggests that it consumes rice when available (Johnsgard 1978).
Breeding Site The nest is constructed from dry grass, leaves and other vegetation, and is built among tufts of herbaceous vegetation on the ground at the water's edge (del Hoyo et al. 1992, Young and Rhymer 1998, Young et al. 2000, Young 2013).
A. melleri is among the largest species of wildfowl found in Madagascar and is widely hunted and trapped for subsistence (and rarely for sport) (Ellis-Joseph et al. 1992, Scott and Rose 1996). Interviews with hunters at Lake Alaotra suggest c.450 individuals are taken each year, constituting 18% of the global population (Randriamahefasoa 2001). Long term deforestation of the central plateau, conversion of marshes to rice-paddies and degradation of water quality in rivers and streams, as a result of deforestation and soil erosion, have probably contributed to its decline (Scott and Rose 1996, H. G. Young in litt. 2007, Young et al. 2013). Widespread exotic carnivorous fishes, notably Micropterus salmoides (although this may now be extinct) and Channa spp., may threaten young (H. G. Young in litt. 2007, 2012) and cause desertion of otherwise suitable habitat (Kear 2005). Its decline on Mauritius has been attributed to hunting, pollution and introduced rats and mongooses (Ellis-Joseph et al. 1992, H. G. Young in litt. 2007) as well as possible displacement by introduced Mallard Anas platyrhynchos (Young and Rhymer 1998), which may also hybridise with this species (Jones 1996, Banks et al. 2008). Pairs are very territorial and susceptible to human disturbance (H. G. Young in litt. 2007), particularly when nesting and will typically desert areas following human arrival (H. G. Young in litt. 2016).
Conservation Actions Underway
The species occurs in at least seven protected areas, and an additional five new protected areas have recently been established that benefit this species, including at Bemanevika, the Tsaratanana-Marojejy corridor and Lake Alaotra (Razafindrajao et al. 2017). It is also known from 14 Important Bird Areas (78% of eastern Malagasy wetland IBAs) (ZICOMA 1999). No regular breeding sites are known. In 2007, there was a drive to increase the number of institutions that keep the species in captivity (Young 2007). It is a nationally protected species. Ex situ captive breeding programmes are underway in Europe and North America (H. G. Young in litt. 2016). The proportion of protected habitat within this species's range has increased from 9% to 46% (Razafindrajao et al. 2017).
55-68 cm. Large duck, rather dark brown all over, with narrow paler fringes to feathers on upperparts and wider fringes on underparts, superficially similar to a dark female Mallard A. platyrhynchos, but with no supercilium. Head is dark, upperwing has green speculum bordered narrowly by white, underwing conspicuously whitish. Paler grey, rather long bill, with varying dark patches at base. Orange legs and feet. Similar spp. Told from other wild ducks by lack of conspicuous white in upperwing, overall dark appearance, large size, long bill, and whitish underwings.
Text account compilers
Benstead, P., Ekstrom, J., Evans, M., Hughes, B., Khwaja, N., Pilgrim, J., Razafindrajao, F., Robertson, P., Starkey, M., Symes, A., Taylor, J., Westrip, J.R.S. & Young, G.
BirdLife International (2022) Species factsheet: Anas melleri. Downloaded from http://www.birdlife.org on 16/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/08/2022.