I live in swampy Florida, I get pterodactyls in my garage at night, it's weird too like clockwork at 1am it seems they peak. The garage seems relatively well sealed. Are they getting in through the garage door most likely? I've found prallethin works very well but I hate using chemicals. Would prefer to beef up my sealing. Any recommendations on improving garage door sealing?
You don't mention what you observed to decide that it's "relatively well sealed". You can get strips at your local lumber/big box store, which have a built in gasket. Cut and nail/screw them to the outside frame with gasket slightly compressed against the door. Do both sides and the top. That will seal the edges. If the door bottom doesn't have a gasket, nail a rubber one on there too.
That should take care of the door, but my garage is also vented via the soffits, so small flying insects will always find their way in. If you have them in large numbers, investigate their ingress and any attractants you may have.