I will just tell it like it is. I know Dr. Bierregaard confirmed what you have suspected, and this in fact the case.
“Might have been a mate replacement. Sometimes when one of the pair doesn’t survive the migration cycle a young new mate fills in and they don’t get all the pieces of the puzzle in place in time.”
I’m sorry to say my second mate Jonathan, did not survive the migration this year. Do not get upset. This is actually a very common event in our lives… On the way home this year a young Osprey took up with me and we became friends. His name is David. He is two-years-old and has spent the last year and 1/2 in Brazil. David is excited about returning to his birthplace. He was born in the Chesapeake Bay near a place called Gloucester.