I just tried googling about the manucodes. Didn't get much, but (and this is largely supposition) I think the original birds would have come to San Diego in the 1980s. There were several collecting trips by American zoos during that decade (e.g. https://journals.tdl.org/watchbird/index.php/watchbird/article/viewFile/507/491), and the San Diego timeline (available online) mentions 1989 as when an "expedition" returned from New Guinea with animals for the zoo. The manucodes bred at San Diego in 1991 (I found a reference in IZY). Anyone with a set of IZY could check for any other breedings after that year. If they only bred once then the youngest bird would now be 26 years old which would be excessive.Indeed, but in the chatroom someone said they thought it was still alive but I suspect they're mistaken or I misread them.