Using the rope, they pull the branch downward, bending it. They then use a bent stick or rock to hold the noose to the ground, keeping the branch tense. A sprinkling of vegetation camouflages the noose.

When an animal budges the stick or rock, the branch springs upward, closing the noose around the prey. If the creature is light enough, it will actually be hoisted into the air.

I think I’ve seen this.