I don't know the answer for sure, but I'd bet they can see colors, since
they all have 'color-coded' speculums. That's the colored feathers near the
middle of the wing. Mallards have blue, our teals have green, etc...
Presumably they identify each other in flight by these colors.

Rick Romea
Seattle, WA
rromea at stioptronics.com

206-523-5831 (Home)
425-827-0460 X 316 (Work)
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If you feel like everything is under control,
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