Female Smew
Smew are described as compact diving ducks with delicate bills. Personally I’d call them dinky. The males are stunning bridal white with a black mask with green iridescence and a black back.
The females are a subtle variegated grey with reddish-brown heads and distinctive white cheeks. Here are a couple:
They are winter visitors from Scandinavia and Russia but there are very few of them and they’re a real treat to see. Sometimes birds escape from freezing weather in Holland and Denmark and appear around the UK’s coast.
These two were in The Regent’s Park as part of a wildfowl collection. I’ve not seen one in the wild.