I'd rather be very picky about this. What's the best way to explain (to bright students) why there's no current in a bird when it sits on a high tension wire? i.e. when a student points out that it creates a parallel circuit with resistance in the wire in the ballpark of 5 times 10^-7 ohms, and resistance in the bird of, say, 10,000 ohms. Or, is there a current in the bird, (nano-amperes?) which is absolutely harmless?