Main author: Stina Andersson, September 2015.
Supplemented by: Simon S. Christiansen & Magnus Hellström, September 2015.
Citation: Ottenby Bird Observatory. 2015. Ringers’ DigiGuide – Aegolius funereus. www.ringersdigiguide.ottenby.se
Summer SC* sp
Winter – –
Young sp: The post-juvenile moult includes the body, LC, MC and all GC, but not remiges, PC or TT.
Adult SC: The post-breeding moult (May-August) is complete but suspended. Body, wing coverts and (whole or part of ) tail and a serial sequence of PP and SS are included. The pattern may at times be slightly irregular, but the following simplification may serve as a useful pointer for most individuals: In the first post-breeding moult (2cy summer) outermost 2-6 PP and innermost 2-5 SS and TT are moulted. In the second moult (3cy summer) 2-5 central PP and some central SS are moulted. In the third moult (4cy summer) inner PP and outer SS are moulted and a new second wave in the outer PP and inner SS are initiated, but note that Hörnfeldt et al. (1988) states that many 4cy still retain juvenile innermost P10 (and, hence, may show four different generations of PP).
Moult of PP in 2cy (n=188) and 3cy (n=11) Boreal Owls at Ottenby during the autumn invasions of 2008 and 2012.
No plumage differences.
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