[Tweeters] Rock Pigeon deterrence

[Sally Alhadeff via Tweeters]

Hello fellow Tweeters. 
Has anyone had success deterring Rock Pigeons from entering into outbuildings using ultrasonic sound devices or other technology solution? My parents’ old farm shop in rural Thurston county has been invaded by 7 pigeons.  
It’s not practical to enclose the area above the sliding barn door. 
Any info or experience would be appreciated. 

Thank you, 

Sally Alhadeff
Sallya at scattercreek.com