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).

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).

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).

Conservation Actions Proposed
Conduct wide-scale status surveys of eastern wetlands. Study its ecology, including movements, to identify all causes of its decline. Promote development of captive breeding programmes.