Noticed this red-sided bird for the first time today in the gaggle of Mallards present year round at Jenney Mill Pond. In looking through various books and scanning photos on the web, I find nothing like this plumage. My initial thought was that this is a hybrid. The dark rusty sides would appear to have come either from an American Wigeon or possibly a Northern Shoveler. The only other clue that I see is the amount of white in the vent-flank area and notice that it reaches well up on the torso - more like a Shoveler than an Am. Wigeon. Yet the rusty coloring on the flanks doesn't continue as saturated toward the rear as it shows in photos for a Shoveler. My guess was most likely a Wigeon; in any event, an interesting bird! But....

After posting these images on MassBird I received feedback from more experienced birders, and the consensus was NOT a hybrid - just an odd Mallard variant resulting from the crossing with a domestic bird which can sometimes produce this odd flank color. I received no insight as to how or what kind of domestic it might have crossed with- just a headscratcher! Nevertheless, an interesting bird.