Hybrid Ducks
Ducks hybridise readily, in captivity and among wild bird populations. Identifying hybrids is fraught with difficulties. Not only are they highly variable but they do not always simply show a mix of each parent species' features. Indeed there are instances of hybrids bearing a more striking resemblance to a third species than to either of their two parent species.
The following hybrid combinations are discussed below (click on any to go straight there or scroll down):
- Mallard x Egyptian Goose
- Mallard x Muscovy Duck
- (Eurasian) Wigeon hybrid?
- (Eurasian) Teal x Green-winged Teal
- domestic Mallard x Yellow-billed Duck
- (Northern) Shoveler x Blue-winged Teal
- Unknown hybrid - possibly Silver Teal x ??
- Ferruginous Duck x ? Red Shoveler
- Pochard x Ferruginous Duck
- Pochard x Tufted Duck
- Hooded Merganser x Smew
Mallard x Egyptian Goose
An unusual combination: this party of four birds was present at Swanton Morley from late August to late September 2007. There appear to be very few documented records of this hybrid.
Two birds reappeared the following February, presumably two of the same four although by this time one of them had a completely dark head:
Mallard x Muscovy Duck
Domestic Muscovy Ducks often hybridise with Mallards (themselves frequently domestic). Personally I've rarely encountered them in the flesh, but there is an abundance of photos on the internet. Many are obvious but I'd overlooked this one as a domestic variant of Mallard until Joern pointed it out.
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Probable domestic Mallard x domestic Muscovy Duck hybrid, Salthouse (Norfolk, UK), 16th February 2008 |
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(Eurasian) Wigeon hybrid?
Vagrant American (and escaped Chiloe Wigeons) do occasionally produce hybrid offspring with local Wigeons, but the identity of the following birds is not so clear - the favoured view seems to be that they are "extreme" but pure Eurasian Wigeons.
It is perfectly within the normal range of variation for Eurasian Wigeon to show a small green area behind the eye but an extensive green band is not normal. Rarely birds do show this though, and it is not entirely clear whether this is simply an extreme of the variation shown by pure Eurasian Wigeon, or if it's a result of hybridisation with American Wigeon (or perhaps another species) some generations back. First generation hybrids are variable but can be expected to show more clues to a hybrid origin than these birds (such as pink bleeding into the grey body, speckled lores/ear-coverts, etc.).
Usually (and in the first example below) the extent of the green head band is the only atypical feature, and for this reason, along with the fact that many pure Eurasian Wigeons show a little green behind the eye, most commentators seem to favour the view that this is simply variation within Eurasian Wigeon - or perhaps a gene that is present in all Wigeons but normally dormant, expressed in just a very few.
However, it is likely that hybrid Wigeons are fertile, and backcrosses must be likely to appear occasionally - what would they look like? The fact that green-banded Wigeons are (apparently) more frequently recorded among Asian populations of Wigeon where vagrant American Wigeons are rather less rare might lend some support to the idea that this is what we're dealing with at least in some instances.
The first bird shown below looked exactly like a Eurasian Wigeon with a green band behind the eye. I had originally thought that the small triangle of green at the rear of the yellow forecrown was also unusual but further study has established that this occurs on a minority of apparently pure Eurasian Wigeons.
The second bird was seen rather briefly before the whole flock was disturbed and flew off. My brief impression was that it was a similar bird to the last but the photographs reveal an intriguing pale collar. It also has a couple of dark feathers in the flanks, but I imagine these are unmoulted juvenile feathers rather than evidence of another species involvement. Three days later there were at least 2 similar birds (but without the dark flank feathers) present, one shown here, and these too showed a pale neck collar. Such pale collars can appear on Wigeon, but this seems to be more common on birds with a little green behind the eye. Note that this site has played host to a hybrid Eurasian Wgeon x American Wigeon in some previous winters.
Thanks to those who have commented about these - any further comments would be very welcome!
(Eurasian) Teal x Green-winged Teal
Hybrids between the North American Green-winged Teal and its Eurasian counterpart are occasionally found in either region. Some show the prominent white vertical bar of Green-winged Teal as well as the prominent white horizontal stripe of Eurasian Teal whilst others, like this one, show a much weaker vertical bar and others can apparently be even more cryptic.
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Hybrid (Eurasian) Teal x Green-winged Teal, Salthouse (Norfolk, UK), 10th February 2008 |
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Domestic Mallard x Yellow-billed Duck
These two ducks almost certainly emanate from captivity as they shared a duckpond with a variety of escaped (or deliberately released) ducks. The first one resembles a Yellow-billed Duck but several inconsistencies including the green on the head and the curled tail feathers indicate some Mallard influence. The pale colouration of the second bird suggests that the Mallard influence was of domestic stock, which is not surprising given the number of domestic birds sharing the pond.
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domestic Mallard x Yellow-billed Duck hybrids, Porthloo Duckpond, St Mary's (Scilly, UK), 3rd October 2007 |
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A return visit to Scillies three years later found a similar, but not identical, pair elsewhere on the same island. The bill was more strongly orange, rather than yellow, and they lacked green on the head. I'm not sure I'd reach this conclusion if it wasn't for the birds seen in 2007 but the coincidence leads me to think these may be the same hybrid? The orangey bills and the straight tail feathers make me wonder if these are females whereas one of the birds above was clearly a male.
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presumed domestic Mallard x Yellow-billed Duck hybrids, Porth Hellick, St Mary's (Scilly, UK), 9th August 2010 |
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Meanwhile the original duckpond where the first pair had been observed in 2007 now contained a number of domestic ducks and this peculiar bird. Could it be a backcross between one of the original hybrids and a Mallard? Another possibility perhaps is domestic Mallard x Pintail, as on last visit there were a couple of very strange and possibly hybrid Pintails on the pond. The pink tones to the bill seem hard to explain either way. Any thoughts on any of these birds would be welcome.
Shoveler x Blue-winged Teal
This individual spent a few months at Titchwell. Its appearance is extremely similar to Australasian Shoveler Anas rhynchotis, a photograph of which appears beside it for comparison.
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male Shoveler x Blue-winged Teal hybrid, Titchwell (Norfolk, UK), 7th April 2001 |
captive male Australasian Shoveler for comparison, Blakeney Collection (Norfolk, UK), 18th January 2004 |
Unknown hybrid - possibly Silver Teal x Tufted Duck
This duck was reported on 23rd Feb as a presumed Teal x Tufted Duck. Thinking this sounded interesting I went along to see it the next day. I'm not convinced by the proposed ID but am not at all sure what it is. My initial view was that the similarities to Hottentot Teal were too great to be coincidental, but Silver Teal is also a possible parent. David Russell has kindly informed me that an escaped Silver Teal was present at the site the previous August - this may be coincidental but with little else to go on it's enough to change my speculative view. The second parent is even more speculative, though Tufted Duck is certainly a possibility I can't rule out. Other comments would be welcome. Unfortunately it was a bit too distant for decent shots; my best efforts are here with some commentary below:
Ferruginous Duck x Anas sp., perhaps Red Shoveler
This one was a captive bird; the Anas parent was uncertain but if we assume the parent was still in the same collection (which isn't the case for at least one hybrid seen there) then the most likely choice (in view of the bill shape) is Red Shoveler.
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Captive hybrid Ferruginous Duck x Anas sp., possibly Red Shoveler, Blakeney Collection (Norfolk, UK), 28th February 2009 |
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Pochard x Ferruginous Duck
This hybrid is responsible for a few erroneous claims of Ferruginous Duck in the UK - they seem to turn up here nearly as often as pure Ferruginous Ducks. Some can apparently be more similar to Redhead in appearance.
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male Pochard x Ferruginous Duck hybrid, Martham Broad (Norfolk, UK), 29th November 2009 |
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Pochard x Tufted Duck
Probably the commonest naturally-occurring duck hybrid in the UK.
Hooded Merganser x Smew
I believe this hybrid has occurred in the wild but these ones are captive. These birds (there were two the same, not sure if they're both here or not) didn't look exactly like other Hooded Merganser x Smew hybrids I've seen photographed before so thanks to Joern for confirming their identities.

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