If a hybrid, this is probably not first generation ...
We know that hybrids between the 3 wigeon species Mareca americana, Mareca penelope and Mareca sibilatrix are fertile.
We also know there are aberrant Eurasian wigeons that show green in the head like this bird , but no other clear sign of american wigeon. This bird seems quite pale-fronted , so may have some American genes- bit that´s a general question - does the green in the head of some eurasian wigeons come from the wigeon ancestor, or is it a sign of introgression of American wigeon genes?