This video from Britain says about itself:
14 July 2016
Ducks are usually easy to identify, but the females can be more challenging. Many of our familiar dabbling ducks have subtly-plumaged brown females which, on first glance, appear similar. This workshop will help you tell them apart with confidence.
Dear Kitty. Some blog 
Very useful for ID!
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Thank you! They can be difficult, especially in eclipse plumage.
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