Turns out blue HJ is a very young male bird. He was ringed at Caerlaverock in 2010 as a chick, so he is only 2 years old. Most ospreys don't return to the UK until they are 3 years old, but they have been known to return early to look for mates and suitable nest sites. So HJ is clearly hoping to get ahead of the game.
HJ's mother was unringed but his father was green AW, one of Wigtown Bay's chicks from our female HD and original male BS, hatched and ringed in 2004. So looks like HD's grandson has returned to the nest. Sadly, green AW has not been seen this year back at the Caerlaverock nest, so it's great to see one of his offspring, looking fit and healthy, back in the area. Both HJ and EP have been visiting the nest today. No doubt EP thought his luck was in when a new bird showed up in the area. With 2 males about, maybe we'll have 2 nests next year? Hey, I can but hope!!
Sounds like you'd better spend the winter building nest platforms! Hope they both return next year (and, just as importantly, attract mates).