|This article is about the current version of DF.|
An ambush is a type of attack in fortress mode where a small force of enemy humanoids, typically goblins, attempts a sneak attack on your fortress. While smaller in scope than a full siege, ambushes are not related to the number of dwarves in your fortress, and so can be triggered by relatively small populations.
Ambushes are not announced immediately, and the attacking units are only revealed when your fortress becomes aware of the attackers, either when they set off a cage trap or come sufficiently close to a dwarf, caravan member, or pet (they ignore wildlife). Ambushes can also be discovered manually, but not spotted, if you happen upon on an invader corpse and some goblinite in one of your traps. Once an ambush squad is detected, an ambush will generate a major announcement, the wording of which depends on the invader.
Ambushes, just like sieges, nearly always happen at the end of a season, generally in the last 10-15 days of the season. Ambushes tend to arrive with caravans but can happen any time. Note that goblins will usually ambush with more than one squad (2 to 4), each of which will trigger a separate message and also has to be detected separately. If ambushers are caught in cage traps, they will be marked as Caged Prisoner in the unit screen. These prisoners can be dragged around between cages (or tossed over tall towers) without risk of a jailbreak, unlike goblin thieves. If you abandon your fortress while an ambush is active, you will receive the message "Your strength has been broken." Finally, when the leader of an ambush is killed (or captured), but not the other units, they will stand around and "wait" for their leader; this is probably a bug.
 Types of ambushes
Goblin ambushes are usually announced with the message "An ambush! Curse them!", though this is occasionally modified to "A human has sprung from ambush!" if a captured human leads the squad (human civilizations themselves do not send ambushes, only sieges). Goblin ambushes are attracted by relatively high amounts of wealth; beyond a certain threshold, the higher the wealth, the more attractive your fortress becomes as a goblin ambush target.
Goblins usually enter the map with two to four squads, each of which must be detected separately. On the sliding scale of wealth attraction goblin ambushes lie squarely between thieves/snatchers and sieges, but are infinitely more annoying; snatchers are a mere nuisance and sieges can usually be dealt with, but you might not find an ambush until it's too late to prevent them from entering your fortress and slaughtering your populace (or staying outside of it and killing off your wood cutters, or your plant gatherers, or your livestock, or your fisherdwarvers, or your ambushers, or...). Dealing with the threat of a hidden ambush is an important element in military design.
It may be preferable to avoid goblin ambushes as much as possible by holding wealth down early on, and then creating a large number of high-value objects as possible in a short period of time on the way to "siege level" fortress wealth attraction. This reduces your exposure to ambushes, but means you have to deal with sieges off the bat instead.
Necromancers will also occasionally ambush your fortress, if you are in range of their tower and they opt out of a full-on siege. Necromancer ambushes consist of several necromancers, each one being detected individually; an early warning sign for a necromancer ambush is the presence of undead in non-evil biomes. These ambushes are announced with "An ambush! Drive them out!". The necromancers themselves are harmless, being regular old unarmed humanoids; however, very bad things will happen if they manage to find their way within sight of any left-over goblin sieges, corpse or refuse stockpiles, or (Armok forbid) last month's dragon invader. For this reason it is highly recommended that fortresses within sounding range of a tower internalize or atom smash all of their meat byproducts, and set standing orders to "gather refuse from outside" and clean up any meaty outdoor bits.
Kobold ambushes are triggered by a long enough string of successful kobold thieveries, and are announced with the message "An ambush! Skulking Vermin!". This usually only happens when kobold thieves manage to steal from an outdoor cache of some sort that your dwarves cannot access for some reason, possibly fallen goblinite from or during an ongoing siege. Kobold ambushes are mostly notable for being much more annoying than kobold thieves, and should not be allowed to occur. It should be noted that the first ambushes from kobold are full of recruits who have never seen a dwarf in their life, and will almost always scatter and run away instead of fighting.
 Adventure Mode
Ambushes also occur often in Adventure Mode. They generally happens while fast traveling, you will suddenly stop fast traveling and a dialogue box will appear, telling you who you're being attacked by. You will then be attacked by a group of hostile creatures. They are almost always Humans, Goblins or Dwarves and their equipment varies widely from armour and iron melee weapons to clothing and bows. They will generally surround you and will not stop fighting until they - or you - are dead.
The best way to deal with ambushers is to attack each enemy until they suffer a bone fracture. This will almost always render them unconscious after a turn or two making them a non factor and prevents them running away. While they are down, focus on their friends.
Archers are by far the biggest threat in an ambush as a bolt has a high chance of striking a bone and rendering you unconscious to be killed in short order. Bowmen and crossbowmen are green colored (unless using a graphics set), so watch out for any green enemies and try to focus on them first if possible. If you are shot at, try to move behind a tree to hide from the archer until the arrows stop flying. Allow the melee attackers to come to you and slice them up as they come close enough. Beware of accidentally dodging into the tree, stunning yourself, or out of your cover.
If you succeed in killing them, you can then run away, keeping trees between you and the archer as much as possible or try to charge them to cut them down in melee. It is a good idea to carry a bow of some kind, even if you are a melee fighter so you can fire back at archers if necessary. All you need to do is nail one of his bones with a projectile and he will probably fall unconscious, ready to have his head sliced open.
Once you have wiped out most of the attackers, feel free to kill crippled ones slowly, cutting or beating them up first to boost your skills. Make sure to check their inventory once they die, you might find some nice armour.
Currently, as of v0.42.04, goblin ambushes do not happen due to it being removed from the raw. Sieges still do occur after your fortress exceeds the population of 80 though.
 See also
|Military and Fortress Defense|
|Guides||Military quickstart • Interface walkthrough • Defense guide • F.A.Q.|
|Soldier Management||Military overview • Soldiers • Scheduling and alerts • Squads • Equipment • Marksdwarf training|
|Design Tips||Military design • Security design • Trap design|
|Invaders||Ambush • Megabeast • Siege • Thief|