All was fine for weeks now. I can only think a) the young fledglings from the other clutch ventured in (

I saw no-one go in again, but it was close to roosting time anyhow. They were well fed at least.
I've placed a nest in with my bengalese, who were in rest, in the last attempt at a plan b incase I have to move survivers.
Any thoughts as to why this would happen now at so late a stage? All my other birds are acting as normal and most are on their own nests so not searching for sites etc. I can only think of the Gouldians doing this to themselves...

Its never smooth sailing.