Yellow-billed Duck x Mallard hybrid

Yellow-billed Duck Anas undulata x Mallard Anas platyrhynchos hybrid

This bird shared a duckpond with a variety of escaped or released ducks. Superficially it resembles Yellow-billed Duck but the green head and curled tail feathers are obvious evidence of Mallard genes.

Yellow-billed Duck x Mallard hybrid, Porthloo Duckpond, St Mary's (Scilly, UK), 3rd October 2007

This one was with the bird above and the pale plumage presumably indicates that the Mallard parent was a domestic bird.

second Yellow-billed Duck x Mallard hybrid, Porthloo Duckpond, St Mary's (Scilly, UK), 3rd October 2007

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. If it wasn't for the birds seen in 2007 I'm not sure I'd reach this conclusion 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.

Yellow-billed Duck x Mallard hybrid, Porth Hellick, St Mary's (Scilly, UK), 9th August 2010

As with the males above, the second bird was pale suggesting a domestic Mallard ancestor.

second Yellow-billed Duck x Mallard hybrid, Porth Hellick, St Mary's (Scilly, UK), 9th August 2010

Meanwhile the original duckpond where the first pair had been observed in 2007 now contained a number of domestic ducks and the next 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 a previous visit I noted a couple of very strange and possibly hybrid Pintails on the pond. The same pond plays host to at least one domestic Mallard resembling the pink-billed "Aylesbury" breed, so if such a bird was a parent this may explain the pink colour on the bill. Any thoughts on any of these birds would be welcome.

possible Yellow-billed Duck x Mallard hybrid, Porthloo Duckpond, St Mary's (Scilly, UK), 7th August 2010

possible Yellow-billed Duck x Mallard hybrid, Porthloo Duckpond, St Mary's (Scilly, UK), 6th August 2010

For comparison, here are photos of the parent species.

Yellow-billed Duck, Nyika (Malawi), 5th October 2008 and Mallard, Seahouses (Northumberland, UK), 5th February 2023

For more photos of these species follow the links below: