Reg Edwards wrote:
It's the current which matters.

The bird has a capacitance to the rest of the world which depends on
its size. The current which flows up the bird's legs is the voltage on
the antenna divided by the capacitive reactance of the bird's body.
For small birds the capacitance is only a few picofarads and so the
current is extremely small. The bird continues to sing its happy
song.

I did surprise an Owl one night sitting astride my Inv-V
center insulator. He was apparently touching both dipole
wires when I went key down with 100 watts.
--
73, Cecil http://www.qsl.net/w5dxp