Here's something else to consider about these raptors that are preying on mostly birds instead of rodents…….The main premise of what I’m getting at with the theory I’m presenting is that there is a higher variance, or bigger swings, happening in the brooding phase than in the nesting phase……The root cause of the swings with rodents comes from swings in rainfall……Its potentially possible that those rainfall swings also impact tweety bird populations as well and drive a higher variance in them just the same. Just a thought…….