For reliable "big movement" ornaments on your tree, these are champions (this is their seventh Christmas, still running strong).

Drinking birds are heat engines. Normally, the head dips into a container of water, then the water evaporates, cooling the head. If the head is cooler than the body, the fluid rises and creates an unbalanced situation, causing the bird to "dip" and the fluid to return to the body. Head cooler than body equals movement. Heating the body creates the same differential situation.

Heat from an incandescent C7 Christmas lamp causes the fluid to rise from the bird's body. The bird "dips" and the process repeats.

Supplies

3d printed bird holders

Drinking Bird

Incandescent C7 lamps

Paper clips

Step 1:

3D print the "bird holder" bracket--print at 102% size.

Step 2:

Bend a paper clip and mount the bird holder to a branch on the tree. Insert the bird into the bird holder.

Step 3:

Slide a bulb into the slot at the base.

Step 4:

When the lights are turned on, it takes about 90 seconds for the lamp's heat to warm the fluid enough for the bird to start bobbing. After that, there's no stopping the little guys.