Stejneger's Scoter

Stejneger's Scoter is a large diving duck in the east of the Eurasian continent. The former taxon Macleae duck has recently been split into 3 new species, the Eurasian Macreuse duck (or simply macreuse duck), the Stejneger's Scoter, which we are interested in here, and which occupies the eastern part of the continent and the White-winged Macreuse duck that occupies the northern part of the North American continent. Stejneger's Scoter has thus become monotypic.
Stejneger's Scoter is very close in all respects to the macreuse duck, to the point that the taxon is not yet recognized by all. It is recognized by the IOC*, hence its inclusion in oiseaux.net.
I will only mention what distinguishes it from the macreuse duck. The adult male in nuptial plumage has an even more exotic beak. The upper mandible is bicolored, red on the culmen and 3/4 of the top, yellow-orange on the remaining quarter. A black line, more or less important, marks the lower limit. The lappet is dark orange. But above all, at the base of the beak, the black swelling is much more developed and overlooks the nostrils, like a wattle. The day can be seen through the joint nostrils.
The female is very similar to the female macreuse duck. Same dark brown plumage, same pale areas on the sides of the head. In some, a slight puffiness is visible in the upstream nostrils, which allows identification.
The juvenile is female type but paler, with larger and paler head spots.
*See Bibliography