I am troubled by this individual female or juvenile diving duck that does not quite fit. I added it to INaturalist

http://www.inaturalist.org/observations/193909811

to get comments and a conclusion on what specific species it is, but so far we are stumped. Characteristic to consider are ruffed flat topped head, brown eye color, lack of gray modeling on sides, dark back and lighter brown sides, bill shape and color. I would enjoy your thoughts. Maybe this is just one of those haunting birds that gets away.
Thanks Bill