Heuglini adult, August 07 2002, Tampere, Finland (61.33N 24.59E).

Features suggesting heuglini in these pictures are upper-parts grey-tone. Birds obvious paler than fuscus. Facial expression: slender bill with ill-defined gonydeal angle. General structure suggest male: fierce facial expression, strong bill, size, square-headed, different from the slender and 'elongated' look of fuscus.
Large mirror on P10, on both webs. Red spot doesn't extend to upper mandible and is rather small and orange-red, well in line with adult heuglini. P5 missing, P6-P10 old, all rectrices and secondaries old as well. Some median and lower lesser coverts are fresh and steel-blue, compared to the slate-grey older wing-coverts.