"Hey Bert, Old Man Jenkins called in another Santa Clause, do you have eyes on a plane around the airport?"
"Sure do, Tina. Small single engine is making it's approach now."
"okay thanks. I'll give you another ring when he calls in for the 243rd time this year..."
Back when I was a teenager in church, some of the local cops would be talking shit about the "crazies" they would arrest, and apparently one guy would call in about UFOs every time the nearest air force base used the training airspace that was overhead. Multiple times a week, and I guess never listened that it wasn't aliens.
The top is the percentage of people while the bottom is the total incidence. This is an apples and oranges comparison. In this case the bottom map is functionally a population map as others have pointed out. Most stats are best in "#/thousand people" or equivalent, but should always in the same unit if compared.
It might be per household vs. people with a firearm registered to them personally? (Note i have no idea how firearm registration works in thr US but it's the first explanation that comes to mind since your source is specifically "adults living in a household with at least one firearm")
Where is the correlation? South Carolina? Some in Arizona? Is the point that there’s more UFO sightings in places with low gun ownership? Please explain.