Chocolate and green

Chocolate and green

Observation - Chocolate and green - UK and Ireland. Description: These two inseparable handsome chocolate-brown and green ducks have been present on Lydney lake for a couple of weeks - they look really stunning in good sunlight. About Mallard size, I presume that they are a Mallard cross, but the other Mallard crosses

These two inseparable handsome chocolate-brown and green ducks have been present on Lydney lake for a couple of weeks - they look really stunning in good sunlight. About Mallard size, I presume that they are a Mallard cross, but the other Mallard crosses present are quite 'blotchy' rather than this rich, smart colour form. Any thoughts on their parentage?