The Blue-winged Teal (Anas discors), left, was photographed in Iowa in May02 and the Cinnamon Teal (Anas cyanoptera) in Colorado in April03. Both actually have blue in the wing. It just happens to be showing in the Cinnamon. The Cinnamon has a longer, more Northern Shoveler-like bill and lacks the dark eye-line.
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Found in a search. (?)