{"fact":"Rooks display impressive tool-related skills, adapting their behavior based on the task.  When presented with sticks of varying weights, they would either drop heavy sticks or push down on lighter sticks to trigger a food platform.","context":"If the aperture size was wide, and the birds were presented with a heavy stick, they would drop the stick into the tube and collect the worm. If the birds were presented with a long, light stick, they would insert the stick into the tube, but push down onto the stick at the same time, adding the necessary force that would trip the platform without weight alone.","source":"Nathan J. Emery, Insight, imagination and invention: Tool understanding in a non-tool-using corvid, 10.1017/cbo9780511894800.006","index":450}