Juvenile blackbird practising nest building?

I left a trailcam recording a blackbird nest after the chicks had fledged, hoping they might return to have a second brood. The parent blackbirds have subsequently set up a new nest elsewhere in the garden for a second brood but I have a few clips of this juvenile blackbird apparently practising repairing/building the abandoned nest it was born in – after these clips it wasn’t recorded at the nest again for the following week and no further use of the nest has occurred so far. I thought this was rather interesting behaviour – it reminded me of a child playing with a doll’s house as though it was practising for when it was grown up! Any thoughts or observations on this behaviour would be welcomed!