The best advice I can share would be NOT to approach any big commercial jobs until you have experience in dealing with the type of problems they have. The worst thing you can do for a new business is get into a project that is way over your head (experience level) and end up failing miserably in the effort to solve the problem.
Start on small scale problems and work up to the point you can approach the larger accounts with confidence. You stated that you don't think they will ever be rid of the birds.... so if you don't think the problem can be solved, why would you want to approach them? Just trying to prevent you from stepping into a sinkhole right off the bat in your new business.
If you are not at the point where you have worked out your pricing structure ( "I am lost as how do you make any money at this" ) the biggest mistake you could ever make is attempting to land a large commercial contract.
Without knowing what type of businesses or structures, it's hard to suggest a solution. However, trapping is a never-ending process. I've done some really big bird control jobs, and netting (or other barriers) is the best method IF the structure design allows.
Visit some of the bird control product websites (Bird-B-Gone, Bird Barrier, etc) and you'll get some ideas on what type of products are out there.