This is in fact a profound question.<p>The physics of electricity propagation in a powerline circuit is fundamentally the same as the propagation of FM radio waves, or even the beam from a flashlight. All of these examples involve electromagnetic energy propagating at the speed of light. So why do we need wires for powerlines, but not for propagating radio signals or light beams?<p>The principle is that light (in a vacuum at least) travels at a constant but non-infinite velocity, c. Hence, the electrical wiggle received at an observer&#x27;s location <i>now</i> i.e; (x,t), has been caused by some <i>earlier</i> wiggle conducted by the source (x&#x27;,t&#x27;) such that the t-t&#x27;=(x-x&#x27;)&#x2F;c. We should expect that the effect of this &#x27;time delay&#x27; is more profound if the source is wiggling faster in time.<p>A more specific way to state this is that the electromagnetic power radiated into free space by a dipole increases as the square of the dipole moment and the <i>fourth</i> power of the frequency. Now compare a powerline (60 cycles&#x2F;sec), with FM radio (100 Million cycles&#x2F;sec), and with the light from a flashlight (500 Trillion cycles&#x2F;sec). That&#x27;s why even atomic dipoles can produce intense visible light, while it would take a very very large dipole to radiate a similar intensity at 60 cycles.<p>Feynman Lectures Vol.II is absolutely the best reference to learn this stuff.<p>That is not to say that a bird <i>needs</i> to make contact with two wires on a utility line, in order to suffer harm. If the line voltage is high enough (e.g; 110,000 Volts, as in high-tension power transmission), an electrical corona would form around the line from electro<i>static</i> effects. The corona is actually ionized air indicating the high electrostatic field strengths in the region, it can emit a bluish glow and growl at 60 cycles. Birds can no doubt sense this corona &amp; stay away.