Subject: how can you get shocked without a path to ground ?

I have a good understanding of electicity but got confused when seeing a 
commerical product that gently zapped squirrels who tried to climb up a bird 
feeder pole. here is the video ...
http://www.youtube.com/watch?v=A3-Hf4tpIkA&feature=related

can you produce current flow (ie the spark or 'zap') WITHOUT a 
path to ground, ie WITHOUT 2 CONDUCTORS. in this case Squirrel is in 
midflight... touches a single conductor and gets zapped? how is this possible?
what kind of electric circuit is used to create this effect? Thank you
 

Re: how can you get shocked without a path to ground ?