Have you seen spawners being built?

[Mendel]

Just a thought that appeared on my head suddenly. I know biters repopulate areas and build new spawners a little distance from my walls but I have never seen it happen.

Have you?

As in, have you been looking at an area where there is nothing but land and then had biters travel to that area and set up a spawner such that the spawner pops up while you are looking at it?
Or have you perhaps seen a new spawner being added to a cluster of them already there?
Also have you seen a worm being born?
Is it even possible to see this happen?

[Muche]

Previously, I have seen a bunch of biters sitting at a spot which they chose, I guess, but I didn't stick around to see a spawner pop up.

With the help of debug setting show-enemy-expansion-candidate-chunks (shows chosen spot as blinking circle on the map), I've found a future spot, put a radar nearby, waited a bit and seen a spawner and a worm appear.

[5thHorseman]

Not in my own runs, but I saw it on YouTube once, I'm pretty sure in MangledPorkGaming's Towns series.

[Killcreek2]

Yes! Once I saw a pack of biters & spitters moving parallel to my walls, which seemed odd as they usually head at the walls, so I followed them out of curiosity.
They stopped in an open area, so I waited like a BBC nature documentarian: After a while some disappeared and worms popped up in their places, then more disappeared and became spawner nests after a short delay.
This was back in 0.13, but I have witnessed it again since then too [it is much easier with the new world view map feature in 0.15].

[Mr. Mechanic]

Just set expansion cooldowns to the lowest possible settings and they'll expand roughly every 3 minutes (I like to call it 'Biter breeding season'). Plenty of chance to observe them. From what I've seen, an expansion group just sits there (the biters don't move at all, unless they spot you), and from time to time a biter disappears and a spawner or worm appears nearby, until the whole expansion group has disappeared.

[Factorie]

I never thought of looking out for that... Haven't stumbled upon it myself yet

[TruePikachu]

I was fooling around with Creative Mode earlier today, commanded my own force of small biters. I've witnessed both spawners and worms spawning.

Incidentially, did you know worms are turrets? If you are on the `enemy` force, their range not only shows up when hovering over them, but also in the map view.

[Hannu]

I saw lonely biters disappeared in 0.12 (or 0.13) but spawners never spawned in such situations even I sometimes searched them. Those biters were very probably left from battles and not intentional expand group. Once I saw when new worm appeared to existing enemy base.

[Aeternus]

Worms I believe spawn from pollution. Biter nests spawn from clumped biters that decide to go and roost. Biters poof and the nest pops in.

[PetWolverine]

I saw a spawner appear while I was in the process of destroying a small nest. I didn't see the critters disappear to form it, due to the chaos of being chased by hundreds of biters from nests I had just nuked, but there was a nest of two spawners, and after I gunned them down, suddenly there was a third one from nowhere.

[AlienX]

Yeah i've seen this multiple times.

A small group of biters will sit in a single area for a minute or two before a spawner, worms or whatever get created at the destination.

[featherwinglove]

I cast my vote as a "maybe" because I've watched aliens form outposts on radar coverage on the minimap in real time, but I haven't seen it happen in a fully rendered view.

Incidentially, did you know worms are turrets?

Funnily enough, AAI programmable vehicles are biters. The mod encodes an invisible biter entity in the vehicle to lead it around by the nose. That's why their path finding is awful.