During an afternoon visit today to Foley Park in Norwich, VT, adjacent to Ledyard Bridge, a flock of 9 diving ducks was seen at a great distance downstream (likely about 1/4 mile away) in the main channel of the Connecticut River to the south of the bridge (thus probably in New Hampshire waters). Through 50X magnification, under dark, overcast skies with a little sprinkle of rain, it was clear that all 9 had light colored “cheek” patches. Because of the distance, the image size was very small and it was not possible to see a lot of detail on these birds, unlike the situation for other duck species present including Mallards, a Green-winged Teal, male and female Common Goldeneyes, and a number of Hooded and Common Mergansers.

The only likely kinds of ducks to show such light colored “cheek” patches are female Black Scoters and Ruddy Ducks. How to distinguish between these two at long range appears unfortunately to be a relatively neglected topic in field guides and other bird identification literature as judged from examining several popular field guides and a quick Google search.

The birds seen today had bills too large for grebes though details of bill structure couldn’t be seen. I also couldn't see any tail feathers or markings across the cheek at that distance.

The crown and back of the neck appeared notably darker than the brownish upper parts on the trunk of the 9 birds. When apparently preening, birds rolled sidewards revealing bright, light colored or whitish, underparts. The bills on at least some birds appeared to be lighter colored than the back of the neck or crown. The flock of 9 birds stayed together, unlike the flocks of Hooded and Common Mergansers present at the same time. The 9 birds appeared to be relatively small in size when compared with more distant Hooded Merganser males.

The observable features on these 9 birds point to their identification as Ruddy Ducks. Had they been female Black Scoters, I would have expected darker upper parts on the trunk, longer necks, darker underparts, and a larger body size.

George Clark
Norwich, VT




  

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