I have a potentially large job at a Big Box store that has pigeon and sea gull problems, along with a few other small birds. They already have a row of bird spikes around the building perimeter, as well as most other landing edges. It is mostly a flat roof, but the exterior walls run up a couple feet above the roof. The building perimeter is the issue.
I watched pigeons and the odd sea gull for about 20 minutes today and what I see is the parapet roof wall tops have a single row of spikes/wires along the front/exterior part of the walls, and so the birds simply land behind them, then just squeeze between them.
My observations lead me to think the obvious solution is another row of spikes. If so, where do you suggest buying several thousand feet of such? And is there a brand and/or size you would recommend?

I've taken the bird control seminar with Bird Barrier.

Biggest tip I can give you is ,
Anyone can buy and install bird control products. The key is knowing what works the best for your application/species/location.
Someone already failed at that location.

Look up Bird Barrier -

https://birdbarrier.com/

Lots of good info and help at that website.

Spikes might work, but you need other control measures to go with them. Trapping to remove some of them, would be a start. Also talk to Bird Barrier, or Bird B Gone. I do know Bird B Gone is in California and shipping to me is fast.

wws