There's absolutely no need to tip the pilot outside of the USA, though you may feel you'll need to if taking a ride anywhere throughout the USA.
Tipping in the USA is common through all industries, so it wouldn't be out of order to tip a pilot.
If you do choose to tip the helicopter pilot you might want to do so when your back on the ground after your flight, before handing over the tip to the pilot directly.
Though the pilot might not be equipped to hold cash so you might want to hand over his or her tip to the people in the helicopter centre.