Indigo hasn’t been actually seen in the box since 18th March when Diamond blocked his entry. I haven’t seen him around the campus either, so he may have left.
Early in the morning, we sometimes hear distinctly Indigo-like wails, coming from the tower roof. However, we have been caught before! Xavier sometimes wails just like a juvenile, and when we see Diamond respond with a ‘chup’, then the likelihood is that it is actually the male, Xavier.
Here are a couple of photos of the adults on the tower (Diamond on the ledge and Xavier on the microwave bracket) and a rather unusual screenshot of Diamond blocking the entry of Xavier to the box. Perhaps just not in the mood for bonding!