Goldeneye Bucephala clangula clangula (Linnaeus, 1758)

Chew Valley Lake, B&NES © Nigel Milbourne 2009

Status:  Uncommon, passage migrant & winter visitor. May occur between October & April with highest counts typically between January and March. Occasional, weather-driven, winter influxes. Declining, undoubtedly due to short-stopping, which results in fewer birds coming this far south.

Breeding:  Scandinavian and North European taiga forests in tree holes near oligotrophic water bodies. The UK population is small, 200 breeding pairs (Woodward et al, 2020), mainly in Scotland and Northumberland thanks to the provision of nesting boxes.

Migration:  Move SW mid-November to mid-December & in response to cold weather in northern Europe (especially due to ice formation). Females & juveniles tend to move further south than males. To date, I haven’t established whether any of the UK population migrates, but I’d guess they will be sedentary.

Moult & plumage:  Goldeneye follow the so-called complex alternate strategy (revised Humphry-Parkes nomenclature), which results in three plumages in the first year of life (juvenile, 1st-winter, and 1st-summer), and two plumages as adults (breeding and non-breeding/eclipse). So, we have the following sequence: Downy plumage, pre-juvenile moult, resulting in juvenile plumage, a first pre-breeding moult, resulting in 1st-winter plumage, a first post-breeding moult, resulting in 1st-summer plumage, an adult pre-breeding moult, resulting in 2nd-winter plumage in males and an adult-like breeding plumage in females, an adult post-breeding moult, resulting in adult eclipse (non-breeding) plumage, and so forth.

Therefore, young Goldeneye occurring at Blagdon Lake will have started their pre-breeding moult and will be assuming 1st-winter plumage, typically between November and January, and will depart in spring in this plumage. While on the breeding grounds they will assume their 1st-summer plumage, this occurs between June and August and lasts in males until October to November, and in females until November to December. Which means birds arriving in autumn at Blagdon may include some showing vestiges of 1st-summer plumage. This will be moulted out in males from October-November into 2nd-winter plumage, which will be retained until June, by which time they will be back on their breeding grounds. Females will assume an adult-like plumage by January, before starting their adult post-breeding moult in May (earlier than males) and after they’ve left Blagdon. To sum up, Goldeneye are likely to be seen at the lake as follows:

Males Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1CY Pre-Juv Pre-Juv 1Pre-B 1Pre-B
Juv Juv Juv Juv/1-W 1-W/Juv 1-W/Juv
2CY 1Post-B 1Post-B 1Post-B 2Pre-B 2Pre-B
1-W/Juv 1-W/Juv 1-W 1-W 1-W 1-W/1-S 1-S/1-W 1-S/1-W 1-S 1-S/2-W 2-W/1-S 2-W/1-S
3CY 2Post-B 2Post-B APre-B A-Pre-B
2-W 2-W 2-W 2-W 2-W 2-W 2-W/2-S 2-S/2-W 2-S 2-S/AB AB/2-S AB/2-S
4CY APost-B APost-B APre-B APre-B
AB AB AB AB AB AB AB/AE AE AE AE/AB AE/AB AE/AB

 

Females Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1CY Pre-juv Pre-juv Pre-juv 1Pre-B 1Pre-B
Juv Juv Juv Juv Juv/1-W Juv/1-W
2CY 1Post-B 1Post-B 1Post-B 2Pre-B 2Pre-B
1-W/Juv 1-W 1-W 1-W 1-W/1-S 1-W/1-S 1-S/1-W 1-S 1-S 1-S 1-S/2-W 1-S/2-W
3CY 2Post-B 2Post-B 2Post-B APre-B APre-B
2-W/1-S 2-W* 2-W* 2-W* 2-W/AE 2-W/AE AE/2-W AE AE AE AE/AB AE/AB
4CY APost-B APost-B APost-B APre-B APre-B
AB/AE AB AB AB AB/AE AB/AE AE/AB AE AE AE AE/AB AE/AB

*note: 2-W female is probably indistinguishable from adult in the field.

Key: Juv = juvenile, 1-W = 1st-winter, 1-S = 1st-summer, AE = adult eclipse (non-breeding), AB = adult breeding.

Blue months are those when Goldeneye are likely to be seen at Blagdon Lake (although sightings in other months have occurred recently, since occasional local breeding has taken place). For each calendar year (CY): The top line shows the moult timing in red, and the resultant plumage that could be seen at the lake, in green, on the line below.

Blagdon Lake: Wintering Goldeneye may be seen on any part of the lake, but favoured feeding areas seem to be along Butcombe Bank, along North Shore to Rugmoor Bay and Top End, diving to a preferred maximum depth of four metres. Dietary items include chironomids, corixids, crustaceans, damselfly nymphs, and some plant materials. Small fish may also be taken.  During the day, wintering birds disperse over the lake to forage, often a drake with one, or several, ducks, but in the pre-dusk period they gather into a flock, or flocks, very often at the dam end, to display and roost. In my experience, this makes counting them easier at this time, rather than trying to do it during the day. It may also have a bearing on an apparent recent increase in the number of wintering birds at Blagdon because I have taken to doing roost counts when, in all probability, most counts in the past have been made during the day. It is a delight to watch male Goldeneye throwing their heads back displaying and calling ‘zeee-ZEEE’ to females. Maximum counts at the lake usually occur in February, although this is probably weather dependent, with harsh weather causing influxes at any time during the winter months.

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Bibliography (sources of information):

  1. Cramp, S. et al. Handbook of the Birds of Europe, the Middle East, and North Africa. The Birds of the Wester Palearctic. Vol. 1. OUP, 1977.
  2. Eaton et al. Rare breeding Birds in the UK in 2022. Brit. Birds 117: pps. 591-656, (Nov. 24).
  3. Reeber, Sébastien. Wildfowl of Europe, Asia and North America. Christopher Helm, London, 2018.

Last update: 12th January 2025