This is a bug of very little consequence as far as the game goes , but Boid class appears to be broken in the 1.3pb . In 1.2 you could drop a boid in the map and it would fly around randomly , in 1.3pb they seem to just fly in a straight line at a fixed height until they eventually fly right off the map to who knows where .
I checked the changelog and the only reference I could find to boid class was some code to prevent them flying off the map ( which doesn't appear to be working all that well ) .
Like I said not really a problem unless you've gone and made a whole load of boid class creatures that no longer seem to function *ahem , cough* .
Don't worry about this, they have been fixed... and then some...