Next, we'll create another animation track, to animate the nest so it starts positioned in the grown tree and then drifts slowly to the ground, wafting like a falling leaf. We want it to exhibit a gentle rocking motion. This is a little more complicated than the simple two-keyframe animation we just did, so we'll do our work in a separate Animation Window instead of the narrow track band on the Timeline Editor. It will animate from 0:35 to 0:45.
Animations are based on Keyframes. To animate a property, you create a Keyframe and define the property values for that frame in time. In the previous example, we had just two Keyframes, for the start and end Scale values. Unity fills in-between values with a nice curve. You can insert additional Keyframes, and edit the curve shape.