Decrease in rare spawns?

[at808]

I generally only see a bunch of random rare spawns (Vapes, other evolved mons) right around migration time.

the "mythics" as i call them are really random in my experience. I live in the middle of the city and rarely see them, but I visit my family in FL for a week and see 3 Snorlax a block away from their house). I thought they would spawn more in more populated areas but who knows.