There is no one deterrent to keep pigeons off (apart from someone in every field with a .22 rifle) so the best way is a combination of bird scarers.
We offer our own range of SCAIROFF wind driven scarers & two styles of gas guns the Bangalore & the Vari-Scary. There is little to choose between either gas guns, both can have stand alone or integral batteries, the Bangalore can have a built in solar panel to charge the on-board battery.
The Bangalore gives more of a "crack" as a bang the Vari-Scary more of a resonance bang.
If you wish for more information on a specific product please call Ian on 07803 596660 or email firstname.lastname@example.org