In today's balmy weathermy wife and walked the riverside trail at North Branch Nature center and came across a group of three large ducks that we are having trouble identifying.  They were dark dabblers feeding along the slower moving edges of the North Branch of the Winooski River.  The most prominent feature that each had were tail feathers that curled up in a small curlicue just above and prior to the prominent tail feather tips. One was very dark and almost irridescent with a bill that appeared to be blueish.  Each also had a speckled white patch on their lower neck.  While dabbling, one showed orange feet. 

Thoughts?