Common Pochard Aythya ferina breeds from W Europe eastwards through C Asia (in band at 40–60° N) to SC Siberia and N China to 120° E, and winters south to N & E Africa, India and S & E Asia (Carboneras & Kirwan 2014). It is currently listed as Least Concern, because when last assessed it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.
Globally, it has an extremely large range in both the breeding season (>16 million km2) and in winter (>11 million km2), and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2). Its population size is also extremely large (1,950,000–2,250,000 individuals; Wetlands International 2012), and hence does not approach the thresholds for Vulnerable under the population size criteria (C and D1). Therefore, the only potentially relevant criterion is A, which relates to reductions in population size. Until recently, the population was thought to be declining slowly, but not sufficiently rapidly to approach the threshold for listing as Vulnerable under criterion A (at least a 30% decline over ten years or three generations, whichever is longer).
New data collated from across Europe for the European Red List of Birds (BirdLife International 2015) indicate that the species has declined significantly in recent years, and that this decline is ongoing. A combination of official data reported by 27 EU Member States to the European Commission under Article 12 of the EU Birds Directive and comparable data from other European countries, provided by BirdLife Partners and other leading national ornithologists, suggests that both the European breeding and wintering populations have declined overall by around 40% over the last three generations (22.8 years, based on a generation length estimated by BirdLife to be 7.6 years). This corresponds well with the strong declining trends evident in the two main flyway populations using Europe between 1988–2012, based on midwinter counts conducted as part of the International Waterbird Census (Nagy et al. 2014). Consequently, the species is now classified as Vulnerable at European level (BirdLife International 2015).
Based on the latest estimates (Wetlands International 2012), Europe holds between 35% (breeding) and 40% (wintering) of the global population, so these declines are significant. A third flyway population (breeding in W Siberia and wintering in SW Asia) also appears to be declining, although this may at least partly reflect recent variation in monitoring effort (Nagy et al. 2014). No recent information is available about the sizes or trends of the two other flyway populations, which breed in C Asia and winter in S and E Asia, respectively (Wetlands International 2012), and which together are thought to comprise around one third of the global population. Depending on whether these Asian flyway populations are declining, and at what rate, then overall the species may qualify for uplisting to globally Near Threatened or Vulnerable under criterion A.
Comments on this proposal are welcome, along with any data on the current sizes and trends of the Asian flyway populations, and any information about the threats affecting this species across its range.
BirdLife International (2015) European Red List of Birds. Luxembourg: Office for Official Publications of the European Communities. http://www.birdlife.org/datazone/info/euroredlist
Carboneras, C. & Kirwan, G.M. (2014). Common Pochard (Aythya ferina). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. www.hbw.com
Nagy, S., Flink, S., Langendoen, T. (2014) Waterbird trends 1988-2012: Results of trend analyses of data from the International Waterbird Census in the African-Eurasian Flyway. Wetlands International, Ede. http://www.wetlands.org/Portals/0/TRIM%20Report%202014_10_05.pdf
Wetlands International (2012) Waterbird Population Estimates: 5th edition. wpe.wetlands.org
Additional data received 9 July 2015
Wetlands International have provided wintering trend data for 1991-2014 from across the global range, taken from the International Waterbird Census Database – please see Word file downloadable from the below link: