two male harriers

the first male has looked pretty much like this for 3 years while the second bird appears to be a new resident but he is in the same territory as a very pale (old) bird that was present for 4 years up until 3 years ago -- surely the paleness and lack of underpart colouration must be a genetic trait inherited presumably from his father the old pale male? None of my birds are colour ringed so everything is to some extent supposition but certain birds are clearly identifiable from year to year on plumage traits and even behaviour and calls -- need to check this female but looks like a returning bird