This video from England says about itself:
15 April 2016
Usually, baby marsh harriers are raised by male-female couples.
However, this nesting season there was an unusual discovery in Oostvaardersplassen national park in the Netherlands. There, a young female harrier divided the food among her chicks in the nest. However, the prey was brought, not by a male bird, as usually, but by an older adult female.
The young birds have fledged now.
Why had the young adult female’s male partner disappeared? Who was the older female? The younger female’s mother? Her older sister? Her new-found love? We don’t know. These were not ringed birds.