Did you know that turkey vultures are among the few birds that hunt by smell? When an animal dies, its carcass releases ethyl mercaptan as it decays. A vulture soaring overhead catches that scent on the wind and follows it down. This simulation runs that whole chain as a living system.
What you're watching
Animals wander; on roads, traffic occasionally leaves a carcass.
Each carcass off-gasses a scent plume that grows as it decays and bends downwind.
A searching vulture that crosses strong-enough scent flares amber and descends.
Birds nearby see the descent and follow — the cascade that crowds a carcass.
The model underneath
Four coupled layers, each simplified but structurally faithful:
Emission — a temperature-sensitive decay curve.
Dispersion — a Gaussian plume carried on the wind.
Search — birds following the scent gradient.
Recruitment — the visual follow-the-leader effect.
Try this
Click the map to drop a carcass, then shift the wind and watch the plume swing. Drag to pan and scroll or pinch to zoom in on a descent — the defaults are tuned to be watchable, and real vulture density is far sparser, since one bird ranges over hundreds of square kilometers.
λ ≈ ρ·a(t). Rises as plumes develop and vultures forage; spikes reset when a carcass is found.
Field parameters
Controls
Click the map to place a carcass anywhere. Watch the plume bend downwind; the first vulture to cross the >-threshold zone drops, and nearby birds follow it in.
Drag the map to pan, scroll or pinch to zoom, 0 to fit the whole valley. Arrow keys pan, + and − zoom.