∀x (In(x, sizeTown) → (Big(x) ∨ Small(x)))
∀x (Big(x) ∧ In(x, sizeTown) → Heavy(x))
∀x (Small(x) ∧ In(x, sizeTown) → Light(x))
∀x (Heavy(x) ∧ In(x, sizeTown) → Still(x))
∀x (Light(x) ∧ In(x, sizeTown) → Unstable(x))
∀x (Unstable(x) ∧ In(x, sizeTown) → Changing(x))
∀x (Unstable(x) ∧ In(x, sizeTown) → Unpredictable(x))
In(bird, sizeTown) ∧ ¬(Heavy(bird) ∧ Still(bird))
¬Still(bird)