Crows are found to be in the calm state until disturbed by the player, sending them into an enraged (sprint) state, and worms once spawned are immediately alerted by default, unless the player is sneaking. NOTE: Certain Infected such as worms and crows have different states. They proceed to move at their fastest speed. Occasionally in higher difficulty areas the infected may be enraged by default once they detect the player. Sprint state is the state wherein the infected are angered and sprints toward the players gradually taking small walking breaks in between sprints.They proceed to move on their third slowest speed. Alerted state is the state wherein the infected are alerted because either the player got too close to an infected, entered it's line of sight or shot a bullet near one making them notice the nearby player.They proceed at their second lowest speed and often stagger randomly. Calm state is the state wherein the infected are walking very slowly and not paying any attention to trespassing survivors.This is the only state that can be produced by player damage, once in this state, they proceed at their lowest speed. Crawling state is the state wherein the zombie may be injured by the player and sent to the floor or may be set by default when disturbed by the player.Take these values as estimates, not facts. Infected health and experience values get changed every now and then due to Nerotonin-4 mutations.There are also several factors, like all kinds of movement (note that movement attracts infected individually) and fighting noise, that will increase 'Aggro' (Aggression), or more exactly, the number of infected that may spawn nearby. The health points of all infected stated here is only at the best accuracy from the actual health value. As you move into the higher level areas, however, progressively tougher infected will appear, some easily identifiable by their unique, mutated body types, and others may sprint at you enraged when you least expect it. When you first venture into the city, infected appear infrequently and are easy to kill.

Burnt eyeballs