When analysing the translational motion of a rigid body, we can assume the entire mass of the body to be concentrated at its CM.
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We can also assume that the entire weight of a rigid body acts at its CG. For this toy bird, weights cleverly positioned in the tips of the wings positions the CG of the bird just BELOW its beak. With the CG below the pivot, this bird is basically a pendulum.
xmPhysics 