The Status and Occurrence of Common Pochard (Aythya ferina) in British Columbia. By Rick Toochin. Published: June 3, 2023.

 

The Common Pochard (Aythya ferina) is a species of waterfowl that breeds in well-vegetated eutropic to neutral swamps, marshes, lakes and slow-flowing rivers with areas of open water and abundant emergent fringing vegetation (Kear 2005), but also breeds on saline, brackish and soda lakes, occasionally even in sheltered coastal bays from western Europe, in a band at 40–60° N east through Central Asia to south-central Siberia, into northern China to 120° E, with localized breeding in Southeastern Hokkaido (Cramp and Simmons 1977, Madge and Burn 1988, Brazil 2009, Carboneras et al. 2020). Although not shown in Brazil (2009) as breeding in the Russian Far East, the Common Pochard is an uncommon breeder on the Kamchatka Peninsula (Howell et al. 2014). This species is still fairly abundant, with a global population estimated to number 1,950,000–2,250,000 individuals but shows a long term decline in numbers (Wetlands International 2012). The Common Pochard is a highly migratory species wintering south to North and East Africa (Madge and Burn 1988), throughout the Middle East into Iran, Afghanistan into India, across southern Asia to southern China, Korea and Japan; on larger lakes, reservoirs, fishponds, mineral extraction pits, brackish coastal lagoons and tidal estuaries, but ranging from oliogotrophic upland waterbodies to lowland eutrophic lakes (Cramp and Simmons 1977, Kear 2005, BirdLife International 2021, e-bird database 2021).

 

Overall European breeding population estimated to be decreasing by 30–49% over three generations (22.8 years) (Fox et al. 2016, BirdLife International 2021), with European winter population following a similar trend. Since Europe holds 35% of global population (40% in winter), such declines are globally significant (Fox et al. 2016. BirdLife International 2021). Furthermore, some Asian populations (in Bangladesh, Japan, and South Korea) are reported to be decreasing (BirdLife International 2021). Declines probably due to excessive hunting and habitat destruction and change, with eutrophication an important factor in loss of some suitable habitat; this process promotes development of phytoplankton-dominated wetlands, with opaque rather than clear water, leading to decline in bottom flora, especially Chara, on which this species is so dependent (Kear 2005, BirdLife International 2021). On the positive side, this species has benefited from waste discharge outfalls from food-processing plants, which provide suitable feeding opportunities (Kear 2005, BirdLife International 2021). The Common Pochard is sensitive to disturbance during breeding season (Kear 2005). This species was not regarded as a species of conservation concern until 2015, when information suggesting that the population has declined rapidly across the majority of its range caused the species to be classified as Vulnerable (BirdLife International 2021).

 

There are no accepted records for Eastern North America, despite well-documented photographed record from Saint Barthelemy, Quebec, May 2-11, 2008 (Bannon et al. 2008). What is interesting about the lack of records along the East Coast of North America, is that the Common Pochard has bred in Iceland (Mullarney and Zetterstrom 2009) where there are over 227 records through 2006 (mostly from April to June, peaking in May) (Howell et al. 2014). This species has occurred as a vagrant in the Azores and in winter on Cape Verde Islands (Howell et al. 2014). There is also a winter record of 4 birds from Barbados (Norton et al. 2011). It is highly likely records will increase on the East Coast of North America with future scrutiny of waterfowl flocks.

 

Only in Alaska, does the Common Pochard occur with any frequency in North America (Dunn and Alderfer 2017, Carboneras et al. 2020). This species occurs as a rare spring migrant in the Central and Outer Aleutian Islands, and is very rare at St Paul, and casual at both Gambel, on St Lawrence Island and Nome (West 2008). There are 2 fall records for Middleton Island (September and October), with winter records from the Kenai region, and Kodiak Island (e-bird database 2021).

 

Along the west coast of North America, this species is an accident vagrant in California where there are only 5 winter photographed records accepted by the California Bird Records Committee (Hamilton et al. 2007, Tietz and McCaskie 2020). There are no accepted records for Oregon by the Oregon Bird Records Committee or Washington by the Washington Bird Records Committee. This species is a recent addition to the avifauna of British Columbia (Toochin et al. 2018) with 2 recent records from the winter of 2020-2021 (D. Cecile Pers. Comm.). 

The identification of the Common Pochard is covered by most standard North American field guides.  Birds measure between 42–49 cm in length (Snow and Perrins 1998); with males weighing 585–1240 g, and females weighing 467–1090 g (Kear 2005); and they have a wingspan of 72–82 cm in length (Snow and Perrins 1998). Ages of birds differ, with adult appearance attained in first year; sexes differ in appearance; seasonal variation is distinct in males (Howell et al. 2014). Complete pre-basic molt in the late summer-fall in males in breeding plumage; proceeded in summer by partial Presupplemental molt (into eclipse head and body plumage); both sexes likely have a partial prealternate molt in the spring, although appearance may not change appreciably, except possible first year males (Howell et al. 2014). Partial to incomplete preformative molt occurs in the fall to winter period which usually includes the tail; subsequent molts like adult (Howell et al. 2014).

 

Adult breeding plumaged male holds plumage from September to June (Howell et al. 2014). Birds at this age have a rufous-chestnut head, blackish breast, upper mantle, undertail-coverts, rump and tail, body grey with vermiculations, becoming darker on upperwing-coverts, paler and more uniform silver-grey on flight feathers, with darker tips to primaries and secondaries, and almost white underwing; bill usually dark grey with black nail and broad, pale grey subterminal band; legs and feet bluish grey, and bright orange-red eyes (Mullarney and Zetterstrom 2009, Brazil 2009, Dunn and Alderfer 2017). Female-like eclipse plumage is held from June to September (Howell et al. 2014), always has greyer body than latter, more contrasting dark breast, and no well-defined facial pattern (Mullarney and Zetterstrom 2009, Brazil 2009, Dunn and Alderfer 2017). Female has dull-brown head with pale grey eye-stripe, throat, lores and cheeks (pattern very variable), greyish-brown body, becoming darker above, wings as male but overall browner; bill dull grey to blackish, with broad black tip and broad, pale grey subterminal band, and eyes warm brown (Mullarney and Zetterstrom 2009, Brazil 2009, Dunn and Alderfer 2017). 

 

Juvenile resembles adult female but has more mottled underparts, duller head lacking eye-stripe, has pale grey or white vermiculations on some body feathers, and mantle, breast and flanks are dark grey; appears to take more than one year to achieve full adult plumage; young female distinguished from male by having uniform grey-brown mantle, scapulars and tertials with olive fringes, brown-grey wing-coverts and unflecked white tips to secondaries (Mullarney and Zetterstrom 2009, Brazil 2009, Howell et al. 2014, Dunn and Alderfer 2017).

 

Common Pochard is similar looking to Redhead (Aythya americana) and Canvasback Aythya valisineria) which are common in British Columbia and North America. Redhead has a more rounded head shape; male has yellow iris which is red for Common Pochard; and a pale base to the bill with a light band and a black tip (Howell et al. 2014, Dunn and Alderfer 2017). Female Redhead has a rounded head, buffy head and back that are uniform in color which differs from the Common Pochard female’s dark bill colour that has a light band across the bill towards the dark tip and has whiter flanks (Howell et al. 2014, Dunn and Alderfer 2017). Male Canvasback (Aythya valisineria) is larger and overall paler than a male Common Pochard, and has blackish wash to head, flatter forehead and much longer, all-dark bill (Howell et al. 2014, Dunn and Alderfer 2017). It is important to note that some variant Common Pochard individuals can have an all-blackish bill (like Canvasback) or a narrow, pale, subterminal band and black tip like that found on a Redhead (Madge 1991, Howell et al. 2014, Dunn and Alderfer 2017). It is also important to note bill variation and plumage variations can be found in Tufted Duck (Aythya fuligula) × Common Pochard hybrids) (Mullarney and Zetterstrom 2009). Another pitfall in identification of the Common Pochard are hybrid Canvasback x Redhead (Haramis 1982) and Canvasback x Common Pochard hybrids (Vinicombe 2003). It is very critical to take care in identification when faced with potential vagrants of any of these species and in eliminating potential hybrids, which are comparatively frequent (Madge 1991, Randler 2001, Reeber 2002, Mullarney and Zetterstrom 2009, Howell et al. 2014). 

 

The Common Pochard is an accidental vagrant to British Columbia with 2 recent winter records. The first was an adult male photographed by Les Peterson but wasn’t properly identified until it was independently found and photographed by Jody Wells at Summit Park Reservoir in Victoria from November 8-27, 2020 (D. Cecile Pers. Comm.). This bird was interesting in that it was with 3 Redheads, a couple of Canvasbacks, and a large mixed flock of Ring-necked Ducks and Greater and Lesser Scaup. As with all vagrant waterfowl potential escapees from captivity can be hard to rule out with regards to some records. This record should be looked at with caution though as it was found in an urban park, was very tame, and never moved from a small concrete pond area for over 3 weeks. It is of note though that Common Pochard is not commonly kept in captivity in North America (Patten 1993). This could be due to this species overall similarity to Redhead and Canvasback as put forth by Howell et al. (2014). Regardless, behaviour and location of rare waterfowl are all factors on whether a bird is potentially a true vagrant or lost kept bird. Although this is not enough to say definitely it should be one reason for this record to be classified as species identification accepted, but origin unknown. The second record was an adult female found and photographed by Mike Yip at the Morningstar Golf Course in Parksville on December 23, 2020, and was relocated there by John Purves, and observed by others from February 11-16, 2021 (D. Cecile Pers. Comm.). Photographs can be viewed at https://bcbirdalert.blogspot.com/2020/12/rba-common-pochard-in-parksville-dec.html. To have a single Common Pochard in the winter in British Columbia is exceptional, but 2 birds is unprecedented. The second bird moved around a fair bit and was mostly found on a pond on a Golf Course.  As with all vagrant waterfowl potential escapees from captivity can be hard to rule out with regards to some records. In this case there doesn’t appear to be any behavioural reasons that might indicate this bird came from captivity. The Common Pochard is definitely a species that should be watched for in the future in the province. A couple of fall records from Middleton Island, in the Gulf of Alaska, make it highly possible as a future vagrant anywhere along the west coast of North America. The fact there are only 5 accepted records for California make Common Pochard either an overlooked species due to its overall similarity to Canvasback and Redhead or it doesn’t come down the coast very often. Only over time and more occurrences will it be possible to tell.  

I wish to thank Don Cecile for editing the original manuscript and tracking down the information regarding the recent records in British Columbia. Also wish to thank Geoffrey Newell for allowing us to use his image of the male Common Pochard that was found at Summit Park Reservoir in Victoria.

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