VU
Common Pochard Aythya ferina



Justification

Justification of Red List Category
This species has a large range in both the breeding season and in winter, and a large population. Information suggests the population has declined rapidly across the majority of its range, and is projected to continue to decline, and it is therefore classified as Vulnerable.

Population justification
The global population is estimated to number 760,000-790,000 mature individuals, which equates to 1.14-1.18 million individuals in total (Wetlands International 2021). Three flyways are identified, with the following population estimates: North-East/North-West Europe with 100,000 mature individuals (150,000 total); Central & NE Europe/Black Sea & Mediterranean with 350,000 mature individuals (530,000 total); Western Siberia/South-West Asia with 310,000-330,000 mature individuals (460,000-500,000 total). The European breeding population is estimated at 89,700-151,000 pairs, which equates to 179,000-302,000 mature individuals or c. 270,000-450,000 total individuals (BirdLife International in prep.).

Trend justification
The global population was estimated to be between 1.95-2.45 million individuals in 2016, 1.23-1.33 million individuals in 2019, and is currently estimated at 1.14-1.18 million individuals (Wetlands International, 2021). Three flyways have been identified: North-East/North-West Europe; Central & NE Europe/Black Sea and Mediterranean; Western Siberia/South-West Asia. It is estimated that the North-East/North-West Europe wintering population has decreased by 27-32% between 2009-18 (BirdLife International in prep.; Fox et al., 2016), or by 47% in 17 years, i.e., in three generations. The population is projected to decrease by 35% in three generations relative to population levels in 2009 (Nagy & Langendoen, 2020). The Central Europe population is estimated to be increasing in the period of 2009-2018, after a period of decline between 1986-2018 and period of stability between 2001-2018 (Wetlands International, 2021). While recovery has begun, population levels are still well below initial population sizes. The Western Siberian population has uncertain trends, but with strong decreasing tendency for the periods of 2000-2017 and 2008-2017. The population is projected to decrease by 31% in 17 years (Wetlands International, 2021), or by 68% in three generations compared to the population levels in 2008 (Nagy & Langendoen, 2020). 

In Europe, the breeding population size is suspected to be decreasing by over 30% in the past three generations, and is suspected to continue declining at a similar rate between 2004-2021. In winter, the population size in Europe is estimated to be decreasing by 30-50% over three generations and expected to continue declining at the same rate (taken from IWC trends in Nagy and Langendoen 2020) (BirdLife International in prep.). Folliot et al., (2018) reported declines at the scale of the entire Western Palearctic of  ca. 34% over the period 1988–2012, and ca. 35% over the period 2008-2018. Declines in wintering numbers in the west of the range (UK and Netherlands) have been reported, while increases have been observed further east, e.g., Sweden (Brides et al., 2017). Declines have also been observed in subpopulations, such as in four major breeding areas in France (Broyer et al. 2019), in 10/14 regions in European Russia (Mischenko et al., 2020), and in wintering numbers in the UK and Netherlands (Brides et al., 2017). Europe holds between 35% (breeding) and 40% (wintering) of the global population, so these declines are significant. Decreases have also been reported from Azerbaijan and Armenia (BirdLife International in prep.). Populations in Bangladesh (S. Chowdhury in litt. 2015), Japan (K. Ushiyama in litt. 2015) and South Korea (N. Moores in litt. 2015) are reported to be decreasing. Population declines have not been observed in China (M. Ming in litt. 2015) or Mongolia (S. Gombobaatar in litt. 2015). Causes of past reduction are ongoing.

Distribution and population

The species breeds from western Europe through central Asia to south-central Siberia and northern China (Carboneras and Kirwan 2014). It is present throughout the year but may make within-winter movements. European migratory populations winter mostly in north-western and western Europe, the eastern Mediterranean, Black Sea and the Caspian Sea, as well as in Turkey, the Middle East and as far south as sub-Saharan Africa (Hagemeijer and Blair 1997, Carboneras and Kirwan 2014). Birds breeding in east of range winter in south-east and east Asia across the Indian sub-continent as far east as Japan.

Ecology

This species requires well-vegetated eutrophic to neutral swamps, marshes, lakes and slow-flowing rivers with areas of open water and abundant emergent fringing vegetation. It also breeds on saline, brackish and soda lakes and occasionally even in sheltered coastal bays (Kear 2005). The breeding grounds are reoccupied from early March (in the south) to early May (in Siberia) (Scott and Rose 1996) with breeding starting from April-May. During the winter the species frequents similar habitats to those it breeds in, including large lakes, slow-flowing rivers, reservoirs, brackish waters, marshes, weirs (Africa) and flooded gravel pits (Brown et al. 1982, Madge and Burn 1988, del Hoyo et al. 1992, Fox et al. 1994, Scott and Rose 1996). The nest is a depression or shallow cup in a thick heap of vegetation positioned on the ground in shallow water (Johnsgard 1978, Madge and Burn 1988, del Hoyo et al. 1992, Snow and Perrins 1998, Kear 2005). As in the breeding season, the species will shift to coastal habitats such as brackish lagoons, tidal estuaries and inshore waters (where it may associate with sewage outfalls [Kear 2005]) when driven by frost or other compelling factors (Madge and Burn 1988, del Hoyo et al. 1992, Scott and Rose 1996, Snow and Perrins 1998). The species has been recorded to 2690 m in Ethiopia (Ash and Atkins 2009). 

The species is omnivorous, its diet consisting of seeds, roots, rhizomes, the vegetative parts of grasses, sedges and aquatic plants as well as aquatic insects and larvae, molluscs, crustaceans, worms, amphibians and small fish (Johnsgard 1978, Brown et al. 1982, del Hoyo et al. 1992, Marsden and Bellamy 2000, Kear 2005).

Northern populations of this species are highly migratory (Scott and Rose 1996, Snow and Perrins 1998). Those breeding in the milder parts of western or southern Europe are sedentary or only make short-distance movements, often in response to harsh weather conditions (del Hoyo et al. 1992, Scott and Rose 1996, Snow and Perrins 1998), although individuals from some areas, such as France may utilise mulitple localities up to 200 km apart in one winter (Keller et al. 2009, Gourlay-Larour et al. 2012). 

Threats

It is thought that the primary factors that have led to the decline in this species are most likely to be a combination of: (i) loss of breeding habitat in eastern Europe, and (ii) changes in water chemistry (especially from hyper-eutrophication caused by agricultural runoff). The loss of habitat is thought to primarily result from changes in land management; either the abandonment or intensification of management of lowland marshes and fish ponds (Fox et al. 2016). The abandonment of traditional lowland grazing marshes results in succession to scrub and other unsuitable habitats, whilst greater agricultural intensification leads to marshes being drained. Negative changes to fish pond management also arise from either a reduction in fish production or an intensification that leads to greater use of fish food and medication treatments, and an increase in nutrient inputs (Fox et al. 2016).

The species suffers from predation and nest predation by several introduced and native mammals including American Mink Neovison vison (Bartoszewicz and Zalewski 2003), Raccoon Dog Nyctereutes procyonoides, Raccoon Procyon lotor, Red Fox Vulpes vulpes and Wild Boar Sus scrofa. Increased predation levels may be partly related to declines in Black-headed Gull Chroicocephalus ridibundus colonies, with which Pochard often associate for the benefits of predator deterrence; pochard breeding in association with gull colonies apparently benefit from elevated breeding success and female survival (Fox et al. 2016; Väänänen et al. 2016). Invasive carp Cyprinus carpio may also provide competition for resources with this species, and have been shown to negatively impact the Pochard (Maceda-Veiga et al. 2017). 

The species may also be threatened by disturbance from hunting (del Hoyo et al. 1992; Evans and Day 2002; Kear 2005; Balmaki and Barati 2006; Sorrenti et al. 2006; H. Ibrahim in litt. 2016), water-based recreation (Fox et al. 1994, Kear 2005) and from machinery noise from urban development (Marsden 2000). Pochard are permitted for hunting in several eastern European states, which selects for breeding females and naïve juveniles (Fox et al., 2016). The European hunting bag for the Pochard remains high in proportion to declining populations across the Continent (Hirschfeld et al., 2019). Brochet et al., (2019) estimates 30,000 birds are illegally killed/taken per year in North & Central Europe and Caucasus, 5% of the population here, with Azerbaijan responsible for the largest number. This amounts to an estimated 2% of the global population. Eggs have also been sold in the UK. Adults are poisoned by ingesting lead shot (Spain) (Mateo et al. 1998), with one estimate that it accounts for the death of 56,511 Pochard in Europe each year (Andreotti et al. in press); and drowned in freshwater fishing nets with mesh sizes greater than 5 cm (China) (Quan et al. 2002). The species is also susceptible to avian influenza, so may be threatened by future outbreaks of the disease (Melville and Shortridge 2006). 

Emerging threats include climate change and changes to sex ratios. Pochard have a narrow ecological niche, particularly with respect to water conditions which are sensitive to climate change. For example, Jeppesen et al., (2015) highlighted how climate change can synergistically act with water abstraction, leading to salinity increases at wetlands and leaving them unsuitable for Pochard. There is also evidence of an increasingly male-biased sex ratio (Brides et al. 2017), believed to be due to increasing female mortality (suggestions for this include migration stress, and greater predation hunting risk during the breeding season) which may be contributing to global population declines.

Conservation actions

Conservation and Research Actions Underway
EU Birds Directive Annex II. CMS Appendix II. Agreement on the Conservation of African-Eurasian Migratory Waterbirds, for which Waterbird Harvest Specialist Group of Wetlands International (WHSG) (2015) published 'Guidelines on Sustainable Harvest of Migratory Waterbirds'. The cyclical removal of adult fish from an artificial waterbody (gravel pit) in the U.K. attracted nesting pairs to the area by causing an increase in invertebrate food availability and an increase in the growth of submerged aquatic macrophytes. The removed fish (dead or alive) were sold to generate funds (Giles 1994). In the Trebon Basin Biosphere Reserve, Czech Republic, it was found that artificial islands and wide strips of littoral vegetation are the most secure breeding habitats that can be created for the species (nest survival in littoral habitats was improved by reduced nest visibility, increased water depth, and increased distance from the nest to the habitat edge, and nest survival on islands was improved with increased distance to open water) (Albrecht et al. 2006). The use of lead shot in Europe is being phased out, and there is now a CMS resolution for global action (R. Hearn in litt. 2016). The European Water Framework Directive (WFD) adopted in 2000 aims to restore good ecological status to all surface waters by 2027, including the mediation of eutrophication effects (Fox et al., 2016). The Regulation on Invasive Alien Species 2015 (European Commission 2014) includes the raccoon dog as an alien species of concern, with the programme aiming to "coordinate EU-wide actions to prevent, minimise and mitigate the adverse impacts of invasive alien species (IAS) on biodiversity and ecosystem services, the economy and public health" (Fox et al., 2016). 

Conservation and Research Actions Proposed
Produce an action plan for this species. This species would benefit from the protection and maintenance of wetland habitat. Lead shot use should continue to be prohibited and legislation properly enforced. Accurate monitoring of bag numbers in countries where this species is hunted should be implemented and maintained, and these data used to manage harvests sustainably (R. Hearn in litt. 2016); alternatively, diving ducks should be removed from the list of hunting birds (Babayev et al. 2020). Reduce nutrient run-off from agricultural land. If feasible, local control of non-native mammals should be implemented (R. Hearn in litt. 2016). Raise public awareness of the status of international protection. Train hunters in distinguishing the Pochard from similar species which are permitted to hunt. 

Identification

42-49 cm, wingspan 72-82 cm (Snow and Perrins 1998). Breeding male has rufous-chestnut head, blackish breast, upper mantle, undertail-coverts, rump and tail, silver-grey flight feathers and almost white underwing, grey body, dark grey bill with black tip and bright orange-red eyes (Carboneras and Kirwan 2014). Eclipse plumage similar to adult female. Female has dull brown head with pale grey eyestripe, throat, lores and cheeks. Body greyish-brown, darker above. Wings generally browner than those of male. Bill dull grey/black with black tip and eyes brown. Juvenile resembles adult female. Similar species Redhead A. americana very similar but male A. ferina has red rather than yellow iris, different pattern on bill, female A. ferina has different bill colour and whiter flanks. Male A. ferina smaller than Canvasback A. valisineria, which is paler with blackish wash to head, flatter forehead and much longer, all-dark bill (Carboneras and Kirwan 2014). Voice Male generally silent but makes wheezy whistles in display, female makes mainly monosyllabic calls (Carboneras and Kirwan 2014).

Acknowledgements

Text account compilers
McGonigle, K.

Contributors
Choudhury, A., Nagy, S., Langendoen, T., Heim, W., Baccetti, N., Petkov, N., Vogrin, M., Sorrenti, M., Virkkala, R., Raudonikis, L., Singh, R.K.B., Vyas, V., Hearn, R., Balachandran, S., Caizergues, A., Kasambe, R., Ming, M., Ushiyama, K., Solovyeva, D., Chowdhury, S., Moores, N., Gombobaatar, S., Ibrahim, H., Yu, Y.-T., Bai, Q., Fox, A., Westrip, J.R.S., Wheatley, H., Malpas, L., Butchart, S., Ashpole, J, Burfield, I., Ekstrom, J., Pople, R. & Wright, L


Recommended citation
BirdLife International (2022) Species factsheet: Aythya ferina. Downloaded from http://www.birdlife.org on 29/09/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 29/09/2022.