Crow’s weightlifting: how and how heavy a crow lifted with its bill

抄録

An adult Large-billed Crow Corvus macrorhynchos proved capable of lifting weights of 1,100 g with its bill, equivalent to 1.5 times its body mass. It also attempted various other techniques, using its feet, flapping its wings, and using a fulcrum to flip the weight over. The effort used to lift weights varied greatly and was not always consistent with the weight increase; for example, the crow took more than 12 minutes and 23 attempts to lift 990 g but only took 27 seconds and seven attempts to lift 1,090 g. The crow's strategy seemed to change over a series of experiments, from using muscle power to energy saving techniques.