They’re indigenous. Have always been there. Without a UV light at night no one is usually the wiser. That said, if they’re more prolific this year, it might just be what we call “The week / month /year of the _____” (Fill in the blank. Sometimes it’s mice. Sometimes it’s rattlers. Sometimes it’s ground squirrels. Sometimes it’s black widows . . . etc.) Same thing seems to happen along the shore. The week / month / year of whatever. Sometimes it’s sand dollars. Sometimes its (dead) sea lions. Sometimes its ducks. Also, don’t know if you have any around there, but I’ve heard that new construction will stir things up and cause a lot of scorpion traffic for awhile.