self-propelled particles
... that the concept of self-propelled particles can explain why flocking birds suddenly change direction for no apparent reason, or abruptly switch from a flying state to a landing state?
... that the concept of <b id="mwCO0"><a href="./Self-propelled_particles" id="mwCO4" rel="mw:WikiLink" title="Self-propelled particles">self-propelled particles</a></b> can explain why <a class="mw-redirect" href="./Flocking_(behavior)" id="mwCO8" rel="mw:WikiLink" title="Flocking (behavior)">flocking birds</a> <i id="mwCPA">(pictured)</i> suddenly change direction for no apparent reason, or abruptly switch from a flying state to a landing state?