🏕️ Camp Unit Spawning

8t base interval4 camp tiers3 tiles count radius

Every tribal settlement runs a spawn countdown. Each turn the countdown ticks down only if the camp is not already "full" — when it reaches zero, a unit appears and the countdown resets. And the tribe fights back: every unit it loses accelerates the nearest camp's next spawn. Transcribed from Unit.makeDead, Tile.skipImprovementUnitTurns and resetImprovementUnitTurns in the game source; numbers from improvement.xml and tribeLevel.xml.

Kills speed up the next spawn

Every time a tribe unit dies — anywhere, killed by anyone — the nearest settlement of that tribe (straight-line, no range limit) cuts its next-unit countdown to 4/5, rounding down — but only while it is above 4 (Unit.makeDead, Tile counter ×4÷5 integer division):

7 → 5 · 6 → 4 · 5 → 4 · 10 → 8 · 13 → 10 · 4 or less → unchanged

That is the "the timer jumped from 7 to 5 when I killed a unit" effect — the camp rushes replacements as its kin fall. It is per death, so several kills compound in one turn (9 → 7 → 5 → 4), and it bottoms out at 4: a camp can never be rushed below a ~4-turn countdown this way.

Why a kill sometimes changes nothing: the countdown was already at 4 or less (the >4 gate), or the dead unit's nearest settlement was a different camp of that tribe than the one you're watching.
It keys on the dead unit's tribe, not on who killed it — tribe units dying to other tribes, cities or occurrences accelerate their camp all the same.

The pause rule

A camp is "full" — and its countdown frozen — while the tribe's units within 3 tiles (not counting units out raiding) reach the cap:

cap = camp tier (+1…+4) + Tribal Strength bonus (+0…+4)

Camp tier is the settlement's level — Hovel +1 up to Bastion +4 (table below).
Tribal Strength is the advanced-setup option (Passive → Raging; "Tribal Level" in the game files). Each step adds a flat bonus to every camp's cap — Passive +0, Weak +1, Normal +2, Strong +3, Raging +4 — on top of shortening the spawn interval.
Halved (rounded up) if no raidable city is within the tribe's raid range
Never more than a third of the landmass's tiles (small islands cap low)

So a kill near a full camp does double duty: it triggers the ×4/5 acceleration above and can drop the garrison below the cap, un-freezing the countdown.

Reading the two timers on a camp

A camp shows two counters: the next-unit timer and, beneath it, the develop timer (time until the camp upgrades to its next tier). Everything that can move the next-unit timer, from code: −1 per turn while running (frozen at cap — the tile tooltip appends "(PAUSED)"), ×4/5 when one of the tribe's units dies and this is its nearest settlement (while above 4), +2 when the camp develops, and a reset to full when the unit spawns.

The develop timer counts up toward the tier's threshold (each camp also rolls a random head start at placement, up to 10 turns, scaled down at lower Tribal Strength settings). It pauses while a foreign unit stands on the camp tile. On upgrade, the camp starts rolling the stronger tier's units and its next-unit timer gets +2 turns.
The freeze can also flip with no kills at all — raiders leaving or returning, units crossing the 3-tile ring, or a nearby city becoming raidable (the cap doubles).

The numbers

By Tribal Strength (advanced-setup option)

Tribal Strength	New unit every	Camp cap bonus	Raid range
Passive	14 turns	+0	—
Weak	11 turns	+1	14 tiles
Normal	9 turns	+2	16 tiles
Strong	8 turns	+3	18 tiles
Raging	8 turns	+4	20 tiles

By camp tier (settlements develop over time)

Camp	Camp cap base	Develops in
Hovel	+1	20 turns
Outpost	+2	30 turns
Encampment	+3	40 turns
Bastion	+4	top tier

Example at Normal: an Outpost caps at 2+2 = 4 units within 3 tiles — or just 2 if it has no city to raid in range.

Corollaries worth knowing

Camps near your borders feel relentless by design: with a raidable city in range, they tolerate twice the standing force before pausing.
Raiders don't count. Units that leave to raid stop counting against the cap, so a camp can keep spawning while its warband is out.
Standing on a camp stops its upgrade — the develop timer doesn't tick while a foreign unit occupies the camp tile (the next-unit timer is unaffected by occupation; only the cap governs it).
The very first countdown of the game is halved on turn 1.
In co-op multiplayer (all players on one team) intervals scale by 4/(3+players) — more players, faster camps.

Mechanic transcribed from Tile.doTurn → skipImprovementUnitTurns / resetImprovementUnitTurns / countTribeAvailableUnits in the game source; intervals, camp tiers and Tribal-Level knobs are read from the game's XML each patch. The source functions are hash-watched, so a patch that changes the pause rule trips this site's drift alarm. See also Tribes.