I would have to agree that it was more than likely a black rat snake. Im originally from MO, and we have black rat snakes that have alot of red between the scales on the sides and even on the belly, mixed in with the black markings. Black rat snakes are not picky when it comes to food. They will eat mice, rats, voles, moles, baby rabbits, baby/small squirrels, chipmunks, and birds. As far as vibrating the tail, just about all snakes will vibrate their tails when scared. When done in the leaves in the woods, it sounds eerily close to a rattler!! LOL I have had my heart rate increase a few times out in the field when a king or rat has vibrated its tail in the leaves before I saw it!! LOL
Here is a pic of one of my MO black rats...Notice the red coloration on her sides between the scales, it even fades down to her belly......

Brian
>>I'm new to this site,and am NOT a snake hobbyist,nor am I a snake "hater." There are lots of good things about snakes,hence my question about this one.I live in NE Arkansas in the Delta region.I was watching a nest of baby wrens growing up in one of my flower pots on my front porch,keeping citronella candles lit to keep mosquitoes down,ect.Having so much fun watching them.The flower pot was sitting on a wrought iron stand off the ground.I realize that doesn't matter one iota to a snake.This AM I with horror saw that the babies were gone suddenly.On the porch I found the culprit sunning himself.He was about 4' long,black on top,with a reddish pattern on the underside.We commonly call this a "king" snake in our area,however,I know there are lots of snakes around here that could be classified as a king type snake,they are usually docile,but he wasn't as when I got close enough to look at him really good,he coiled somewhat and made some buzzing with his tail,and no,he definately wasn't a rattlesnake nor was he posionous,I grew up knowing the difference from an early age,having cottonmouths regularly appear in the yard.(Unless there was a "king" snake around.)Do you know what he/she might have been,besides satified (NOT lol.)Thanks.
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RATS
1.0 Corn snake "Warpath" (KY locale)
0.0.1 Corn snake (KY locale)
1.0 Black rat snake "Havok" (KY locale)
1.1 Black rat snakes "Reaper and Mystique" (MO locale)
1.0 Albino Black rat snake "Malakai" (Dwight Good stock)
1.0 Everglades rat snake "Deadpool" (Dwight Good stock)
0.1 Greenish rat snake "Rogue" (Dwight Good stock)
0.0.1 Great plains rat snake (TX locale)
1.0 Grey rat snake "Punisher" (White oak phase)(Dwight Good stock)
RACERS
1.0 Eastern Yellow Belly racer "Nightcrawler" (MO locale)
KINGS
1.1 California king snake "Bandit and Moonstar" (Coastal phase)
1.0 Prairie king snake "Bishop" (KY locale)
0.0.1 Prairie king snake (KY locale)
0.1 Black king snake "Domino" (KY locale)
1.0 Desert Kingsnake "Gambit" (TX locale)
0.1 Florida Kingsnake "Shard"
MILKS
0.0.1 Eastern/red Milk intergrade "Cable" (KY locale)
0.0.1 Eastern/Red Milk intergrade "Omega Red" (KY locale)
0.0.1 Eastern Milk snake (KY locale)
BULLS/GOPHERS/PINES
0.1 Sonoran Gopher "Husk"
Good luck and Happy Herping
Brian