Mareca falcata (del Hoyo and Collar 2014) was previously placed in the genus Anas.

This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is large, and does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Breeds in south-east Siberia, Russia, south to northern Mongolia, China and Japan. Birds then migrate south, with most wintering in the Korean Peninsula and (especially) China. Smaller numbers winter more widely across south and south-east Asia, from north-east India, Nepal (rare) and Bangladesh east to Myanmar, Thailand, Lao PDR (numerically few records, but probably regular) and Viet Nam.

The population size of this species is assumed to be moderately large, based principally on coordinated counts from the non-breeding grounds. A previous estimate of 78,000-89,000 (Cao et al. 2008) is now considered too precautionary, with a revised number of at least c.132,500 derived from a count of c.125,000 in the Yangtze River floodplain in 2019/2020 (Meng 2019, Zhang et al. 2020), c.1,100 in the Democratic People's Republic of Korea, 1,500–4,000 in Japan, and c.2,500–6,000 birds in the Republic of Korea; small numbers elsewhere in South-East Asia counted as part of the Asian Waterbird Census total fewer than 50 birds (Wetlands International 2022). On the assumption that these coordinated counts may have missed some—but unlikely many—birds, the total population is estimated here to be 132,500-150,000 birds, or (assuming a ratio of 0.66), 87,000–100,000 mature individuals.

The species breeds by water-meadows and lakes in lowland valleys, both in open and partly wooded areas. It winters on lowland rivers, lakes, flooded meadows, and, less frequently, coastal lagoons and more rarely estuaries (Madge and Burn 1988). Zhang et al. (2020) found different habitat use during different migration periods, with birds in spring more confined to water and more rarely croplands, while those in autumn mostly used grasslands and croplands. In winter, birds were mostly found using open water near emergent vegetation. A large majority of birds (82%) use stopover sites that are inland (i.e. not coastal).

Hunting for food was probably the biggest threat to this species historically, although this is now likely to affect few birds at only a local scale. A larger threat is likely caused by habitat loss and degradation, particularly the eutrophication and water pollution at some sites in eastern China; land reclamation has also impacted some wintering sites (Zhang et al. 2020). Given that the global population is suspected to be stable, neither habitat loss/degradation, or hunting, are thought to be driving global population declines, although it is acknowledged that in eastern China they may either be causing localised declines, or causing the redistribution of birds to sites further west. 

Hunting for food was probably the biggest threat to this species historically, although this is now likely to affect few birds at only a local scale. Birds are kept in captivity globally (e.g. in wildfowl collections), but the vast majority of these are captive-bred and this is not interpreted as being a threat.

Conservation Actions Underway
The species occurs in a number of protected areas. Protected area designations are thought to have benefitted this species, with the Chen Lake and Wang Lake Nature Reserves declared Ramsar sites in 2013 and 2018 respectively (Zhang et al. 2020).

Conservation Actions Proposed
Continue to monitor non-breeding populations (see, e.g., Zhang et al. 2020) and, where possible, breeding ones.