Hi Bob,
I suggest you are confusing two totally different issues.
First you asked: About “the understanding of moult” and “I have been birdwatching for nearly 40 years I have never come to grips with moult”. Well I would suggest you don’t ask on this chatline, as it is too long to expect people to type it all out for you. As indeed I think it is conspicuous to notice that no one else has commented on that question to help you. I would suggest you read up in any reasonable ornithology text book, that should explain moult to you. I would not suggest a field guide, as that is not usually the role of such a book. Note though that many ducks (unlike most birds) will moult all their flight feathers together, rather than in a progressive sequence. And this bird is clearly doing that.
Second is the issue of the species identity of this one particular bird. Not surprisingly there are several comments from other people on that. That it is clearly moulting is hardly relevant to what species it is (unless of course timing of moult fits one species and not another). I don’t know anything about Northern Pintail but take advice from others that do, and I don’t see any reason to invoke that suggestion at this stage. Not enough there to show it is not a Grey Teal. Hybrid appearances are much harder to predict.
Philip
