Muscovy Duck x Mallard hybrid, Union City Civic Center (California, USA), 29th April 2008 - copyright Doug Greenberg
(photo ID: 2076)
Domesticated forms of Muscovy Duck can be found in many parts of the globe and so too can domestic (if not also wild) Mallards. The two species frequently hybridise but the hybrids are infertile. As domestic variants of both species are highly variable it is no surprise that their hybrids are also very variable.
Muscovy Duck x Mallard hybrid, Rheinauenpark, Bonn (Germany), summer 2004 or 2005 - copyright Joern Lehmhus
(photo IDs: 0848-0850)
The pink and grey bills of the above birds are typical but some are brighter, as shown by one or two of the following birds.
Muscovy Duck x Mallard hybrids, Tattersett (Norfolk, UK), 20th April 2011 - copyright Dave Appleton
(photo IDs: 0295-0296)
Muscovy Duck x Mallard hybrids (three birds, presumably including the two in photo IDs 0295-0296 above), Tattersett (Norfolk, UK), 10th March 2011 - copyright Dave Appleton
(photo IDs: 0297-0299)
Muscovy Duck x Mallard hybrid, Salthouse (Norfolk, UK), 16th February 2008 - copyright Dave Appleton
(photo IDs: 0300-0301)
Some examples of this hybrid can be easily overlooked as domestic variants of Mallard. The long rear end seems to be characteristic and I find the thickness of the legs a good feature to look out for when in any doubt.
Muscovy Duck x Mallard hybrid, Welney (Norfolk, UK), 29th November 2014 - copyright Dave Appleton
(photo IDs: 1766-1769)
Muscovy Duck x Mallard hybrid (same bird as in photo IDs 1766-1769 above), Welney (Norfolk, UK), 10th January 2015 - copyright Dave Appleton
(photo IDs: 1763-1765)
I wonder if the next bird might be intersex, with it's dark slightly greenish head and white semi-collar suggesting male but female-like plumage on body and wings. Or is it just a female, the green on the head coming from Muscovy and the white coming from the bib that's present on some female domestic ducks? I'm not 100% sure it is even a hybrid, but it looks that way to me...
probable Muscovy Duck x Mallard hybrid (with large domestic Mallard), Etherow Country Park, Stockport (Greater Manchester, UK), 6th October 2010 - copyright Steve Graby
(photo ID: 1971)
Steve's next one is more straightforward, even at this angle.
Muscovy Duck x Mallard hybrid, Keswick (Cumbria, UK), September 2012 - copyright Steve Graby
(photo ID: 1992)
Perhaps in life it would have been different, but from the first photo I reckon this one could have been passed off as a domestic Mallard, which may occasionally show pinkish bill colour. But note the short thick legs, the large dark glossy centres to the feathers (especially the scapulars) and the speculum pattern. The stretched wing shot confirms the glossy scapulars and tertials as well as showing the length of the secondary feathers, more or less lacking the white base to the speculum.
captive Muscovy Duck x Mallard hybrid, Edison (Washington, USA), 26th September 2010 - copyright Steve Mlodinow
(photo IDs: 2211-2212)
Muscovy Duck x Mallard hybrid, Farnley Balancing Reservoir (Leeds,UK), 29th January 2017 - copyright Steve Graby
(photo IDs: 3072-3074)
Muscovy Duck Cairina moschata
Mallard Anas platyrhynchos