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0011715Dwarf FortressCreaturespublic2021-03-07 15:092021-03-07 23:37
normalminorhave not tried
PCWindows 10Pro 1909
0011715: Ravens and Giant Ravens get stuck when one of their cluster is captured
I captured (and trained) two animals in cage traps. By sheer coincidence, one was a Raven, and the other a Giant Raven.

The problem is, in both cases, since each was captured, a second member of the same species has been stuck in the map. They never leave, and I feel like now they're taking the "slot" for roaming animals. It's been months and the only wild animals are the uncaptured "partners" of these two ravens. They also just sit around without moving, instead of roaming, so they never fall into the traps.
These two have been there for months, and no other animals spawn.

I believe this might have something to do with CLUSTER_NUMBER, as the minimum for them is 2.

I'm currently trying to reproduce the bug on a new save.
In an embark where Ravens and/or Giant Ravens can spawn, set up a large amount of cage traps outside.
Wait for a Raven to fall into one of them.
Train it.
A second Raven should stick around somewhere in the map, doing absolutely nothing unless approached (which causes it to move elsewhere, but never leave the map)
I only made one change to the RAWs, which was removing the [ACTIVE_SEASON] tag from all civilizations except goblins, in order to make an isolated fort.
No tags attached.
Issue History
2021-03-07 15:09KilokuNew Issue
2021-03-07 23:37PatrikLundellNote Added: 0040961

2021-03-07 23:37   
Yes, this happens, and isn't restricted to ravens or even birds. It's not uncommon for animal groups to refuse to leave if some of them are caught. Note that this certainly doesn't happen all of the time.

The only work around I know of is to kill or capture them the remaining animals. For birds it's a pain as that requires the building of "towers" from which the birds can be attacked (and they tend to move, requiring new towers). It's also possible to use DFHack to kill creatures, but that obviously requires third party tool intervention.

If I understand it correctly, animals in groups follow a "leader", loosely milling about the location of where the leader is at the moment (and I think there's a similar behavior for squads of invaders). It's possible that the logic that ought to elect a new leader when the old one is lost isn't working properly when the leader is still alive but in captivity doesn't work correctly in all cases. However, that's just a speculation.