Each nightjar is a boid: it steers to match the heading of nearby flock-mates (alignment), pulls toward the local group centre (cohesion), and pushes away from birds that get too close (separation). On top of that, every bird also steers toward the nearest moth — when it gets within strike range it "catches" the moth, which respawns elsewhere over the meadow a moment later.
Moth density sets how many moths are on the wing and strengthens the pull each nightjar feels toward its target. Night visibility raises the flock's top speed and how tightly birds match each other's heading — in the dark, nightjars fly slower and looser. Wind gustiness adds a shared turbulence term that shoves every bird off its ideal path, breaking up tight formation flying.
- Trail line from a nightjar to its target — current hunting line.
- Yellow dot — a moth on the wing.
- Flash on a bird — a successful catch.