E57, I would say 12 KV makes a bird fly high enough to see St. Peter!
In truth though... as witnessed a number of times...you get a very nice arc blast, followed by a cloud of singed feathers floating in the breeze. Not much noise -more of a 'pop'- but a real nice flash.
Once had a bird land on a pole-mounted transformer; there was a very loud buzzing sound - like the mother of all breakers trying to trip- a little flicker in the lighting, and no more birdie. Lots of smell of burnt BBQ, though.
(This lasyt happend as I was up a ladder, making a live service connection.... for the life of me, I was SURE I had somehow crossed phases!)
