My civilization has no important leaders, they didn't send a caravan in the fall of the first year, and in the Legends screen they haven't had any events in nearly 1000 years. Are they gone? I'm not getting any more migrants, am I?
It's dead Jim. (random Star Trek reference, lol)
Really though, if they haven't had any events in almost a thousand years, all you'd find are ruins, if they haven't been razed or built over.
Is there any way I could somehow increase my population drastically? I'm willing to abandon and reclaim with a new civilization, but I'd prefer to modify some raws or something to increase my population growth. I've got enough dwarfs for 6 married pairs if I can mate them all off. I already have the [CHILD:12] tag set to [CHILD:2] so I can use child labor, but I don't know how to increase my actual birth rate.
I've played with extinct civilizations before, and the best way to grow them seems to be to let them socialize early and form up into pairs.
You want a lazy fortress at first, with as little work being done as possible, beyond growing food, keeping animals alive, and brewing/cooking.
Create a small meeting area, say 5x5 tiles, and make it the only meeting area. Put sleeping and dining areas very close by. The more compact the fortress is at this point the better.
Your dwarves will socialize with one another a LOT. Within a year or two they will start pairing off into marriages. As they do so, assign the married ones to productive jobs.
Dwarves, once they get married, if kept happy and fed, will pretty much have a pregnancy every year for each married female, from somewhere around age 30 to well over 100.
If you don't have dwarves with social skills, it might be worth restarting and training some social skills on embark. When I did this, I chose the benevolent ones, avoiding liar, etc.
If you need trade early for some reason, just trade food. When starting a no-dwarves world, I Embark with several breeding sets of birds, dwarves set as a 5 skill planter, another 5 skill grower, 5 skill butcher, 5 skill cook, 5 skill brewer, 5 skill mason and 5 skill miner. and you will be able to quickly establish a tiny little fortress. When the digging and mason chair/table/ nestbox work is done, switch them to engraving and improve all the walls of the common areas with smoothing then engraving. Make the rooms substantial in size and engrave them, and they will create lots of happiness.
Do NOT mine a lot, even if you have a married miner. Mining is what sets up moods. Every X mined tiles means a dwarf will gain a mood, and your fortress doesn't want that yet.
This information is dated to the last version, and some of it may have changed. Not entirely positive how much is still accurate but I imagine I'll be corrected on anything that's terribly wrong.
The purpose here isn't to keep dwarves busy though, just make them happy, and feed them. High quality foods