1.When should the rock be dropped?

2.Is the weight of the rock I choose to drop a factor in the plan?

3. How fast at impact do you expect the rock to be falling? (I don't want the bird to be damaged too much although a little pulverization could make for some nice tender morsels.

4. What if I used a catapult that helped me get the boulder off the rock pedestal? The catapult I have handy can release a rock upward at 20 feet per second.

See the images below:

Formula for projectile motion: h (t) = at + vot + ho where a is the acceleration due to gravity (-32 ft/sec or -9.8 m/sec), t is time in seconds, vo is the initial vertical velocity, and ho is the initial height.