At last we had an interested prospector flying around the house yesterday and this morning and it actually entered Box 6 this morning and had a look around. Our three youngsters in Box 3 were still on the nest with the parent bird out for food. The prospector then entered their box whilst the parent was away and it briefly attacked the youngsters. Two of the youngsters then fledged - we saw the second one go at exactly 12.45. The parent then returned with food and a fight ensued, with the remaining youngster hiding away in the corner. At first we thought it was dead as it didn't move for a long time but it was just a bit traumatised and appears to be OK now. Here are some videos:
In the above video you can see the three youngsters in Box 3, and the newcomer having a look in Box 6.In this second video you can see the one remaining youngster hiding away in the corner whilst the parent bird, the one with the full bolus, is fighting with the intruder. This went on for a few minutes, with both birds eventually exiting the box. The youngster appeared a bit traumatised but returned to the nest and at the time of writing, Tuesday late afternoon, is still there. We think it may be away tomorrow though. Hopefully the intruder will return and resume it's inspection of Box 6!