Two enlarged shots showing a pair of Wigeon plus another on the right that is different. Is it a juvenile Wigeon or something else ?
No interactions present.
Female Eurasian Wigeon can be quite variable with some very rufous in colour, and others much duller and greyer.
They won't be in eclipse plumage at this time of year (that is the plumage they have when they are moulting - from mid summer to early autumn). It is possible that your subject bird is a young female, hatched last year, but I doubt that anyone could tell the age from this photo.
The "white eye" in the top photo is probably due to the wigeon blinking! Birds have a translucent eyelid called the nictitating membrane, which can give this effect in photographs.
thanks very much RoyW for your interesting and helpful comments - much appreciated.
Lat/Lng: 51.7204, 0.8083
OS grid ref: TL940061
Mudflats near Osea Island, River Blackwater Essex