What does the meaning if you put salt on a bird tail can catch it mean?

Putting salt on a bird’s tail is not an effective method for catching a bird or having any impact on its behavior. Birds do not have salt receptors on their feathers or skin, so they would not react to the presence of salt on their tails. In addition, most species of birds are capable of flying quickly and would simply escape if any attempt was made to capture them. The notion of catching a bird using salt is largely a metaphorical expression that signifies an impossible or absurd task.