Birds are social creatures. They typically do not live on roofs, but the do relax there during the day between meals, socializing and digesting.
Bird Control Solutions
Professionals typically install products that harass or repel the birds, like Daddi Long Legs or Eagle Eye
Considerations when Selecting Bird Deterrents
It is important to do an accurate assessment, counting the numbers of birds and when they are there.
Be Careful
If birds are nesting on the flat roofs (primarily gulls), consult with your local Fish & Game. The gulls nests are protected, and the gulls may become aggressive as you approach their nests.