Major airports use Green lasers to scare the geese away from the airport. I have tried it with geese and many other birds. Search it on net. Green laser - geese. There's an outfit called Agri-laser and they commercially sell them and teach people how to use them. You don't need to spend the big bucks they cost. Order up a green laser from the bay and discover for yourself. Start at $10 and go up to $100s.. The birds sees the light chasing them and they are scared away. They don't habituate. There's one video showing rank amateur's driving thousands of geese off a lake with an almost toy green laser. WARNING - learn about lasers and how to stay safe. One shot in the eye with a powerful laser is permanent blindness. Your eye reflex is not fast enough to protect you. Lasers reflect off glass, stainless milk tanks, high gloss paint, mirrors, etc. and depending on distance from your eye may be less damaging. When around the dairy I have to make sure I don't get careless and hit the dairy cows in the eyes.
I literally ran off a group of geese pooping in a small park, from my car with a green laser. Don't shine it in their eyes move it along side them so they can see it and sometimes they will just run fast other times they will take to flight.
From my experience. I cleaned out a barn loaded with Starlings with the laser. The birds pooping on the cows and feed created a situation where the farmer was losing animals. After I cleaned them out, without a shot darn it, they found a better place to roost somewhere else. I have done this with two different dairy farmers and screwed myself by losing a bird rich permission. I keep my neighbors chickens off my property with a green laser. So far pigeons seem less afraid of the laser than the other species. Crows, blackbirds...gone in a heartbeat. It has to be green. Has something to do with the frequency of the green light.
Again...read and study laser safety. Realize they can shoot hundreds of yards. They don't lose velocity and drop like lead rounds. There have been cases where people playing with lasers accidentally, and on some occasions purposely, hit the eyes of a pilot. If it's police helicopter they will follow the path of the laser and you will see a stiff fine. I was a search and rescue volunteer with a police agency and our helicopter got lasered and they saw it came from a church parking lot. They landed in the parking lot and enforced the law. It was a bunch of kids on a church sleepover outside goofing off. Still very dangerous and federally illegal. More so with a laser than a rifle, you have to know what your backstop is.
Lighter...I have woods behind my house and it's darn fun to shine the laser up into the woods in the rain or snow. Lots of reflections.