On a reclaimed fort i was surprised to get a Goblin siege army showing up so early (maybe i had too much wealth reclaimed) before any goblin ambush squad came.
I dispatched my 2 squads (one made up of spear+hammer dwarves and the other being only marksdwarves) to try to stop them (as i had not finished my trap system) and the battle was very bloody, victory for the dwarves but they lost many good soldiers.
Anyways, after that victory, at that time the population was around 80.
A season or two after , it was down to 40 dwarves.
What happened is that the military losses resulted apparently into a crazy tantrum spiral (that i wasn't expected as i had not made any meeting hall so dwarves shouldn't have been so close in relationship to each other) that resulted in so many berzerk dwarves, many death by starving (despite they was food available, but tantrum led into people not going to eat) and it was the time in which the stagnant water propagation bug decided to make the full big river (not a small brook, but a big stream) full of "stagnant" water.
And as the dwarves were needing to drink much quicker than my poor brewer was able to produce them, they were dying of thirst.
Only after 40 death, the tantrum spiral ended, and the poor brewer was able to provide drink .
But i fear the next migration will make too much dwarves in the fort again for the brewer, will have to use the reservoir+pump trick to get some water clean.
The coffin making industry was working full time.
But how i hope this stagnant thing bug will be fixed, after a while it's not fun.