I get it. The world is going to hell in a hand basket, and it’s not beyond the scope of reason to be prepared for hungry marauders to come banging on your door, demanding what you’ve got. If you’ve seen the traffic on the 405, that day may be coming soon, like next weekend. But it’s still a little unsettling to watch “Doomsday Preppers” (premiering Tues. Feb. 28 at 9 p.m. on Nat Geo) as some people prepare for the worst by, say, teaching their kids how to toss a tomahawk into someone’s skull. Buying some canned goods, fine, but this seems a bit much, really. Still, I wouldn’t mind picking up a few tips from prepper Michael Patrick Douglas, as a bird call-based alarm system seems very eco-friendly and almost peaceful, except for the running to get your tomahawks part. Watch Douglas in action below.