If a hummingbird stays still for 24 hours suspended in mid-air, what force(s) is preventing the hummingbird from revolving around the earth?

Nothing. There is no force preventing that.

But the humming bird has inertia; so as there is no force (except the lift force) acting on her, she tends to stay in place horizontally relative to Earth.

For the bird to move horizontally by overcoming the inertia, she needs to invoke a horizontal thrust with her wings. At the same time, she needs to maintain the same amount of vertical thrust to maintain whatever altitude she had attained.

Define: "stay still"

Location is relative. If the hummingbird starts revolving around the earth then it would not longer be "still" on the local level.

Gravity. The air around the humming bird moved with the earth too, I forget what that force is called.

The air around us is moving with the earth. If it stayed in the EXACT same area (magically), it would make a round. GENIUS!

global warming