Fri-D: Female Redhead

You'd be tempted to call the right-hand bird a female Ring-necked Duck, since the bird on the left is a fairly obvious male Ring-necked Duck. But. The female bird is a bit bigger, has a rounded crown that is almost flat on top, slightly bigger bill, has no eyering, no white at the base of the bill, is a fairly pale soft brown (the back is certainly not dark). That's a long list of features to rule out female Ring-necked Duck. A scaup? Nope, no pale area behind the bill, too pale overall, and there's a bit of a pale line behind the eye that scaup don't show.  So what is it? What's left? A female Redhead, that's what, one of two that have been pleasing birders at the entrance pond to Edwin B. Forsythe NWR, NJ since November 29, 2013.