In snap-traps with a bait cup, like the T-Rex and Kness-style flat traps, I had been trying to find a solid lure that would fill up most of the space. It turns out that plain M&M’s are a perfect fit.
I put a sticky base lure, like PB, Nutella, of tallow/drippings, into a bait cup and press the M&M onto it, so that the top of the shell is about 3/4 of the way down. There’s a small gap between the edge of an M&M and the bait cup, so rodents won’t have trouble detecting the base lure underneath it.
Compared to a soft lure, a firm M&M is a harder meal to eat. In my traps, mice only nibble a small amount of an M&M per visit, so the odds are high that rats will find traps containing a partly eaten M&M and an intact base lure.
Unlike an exposed lure, which insects and slugs/snails can consume, the hard shell of an M&M shields the base lure. Ants are small enough that they can eat the base lure, but they’re slowed down considerably, because they have to squeeze through the gap between the edges of the bait cup and an M&M to reach the base lure. If ants do consume all of the base lure, the M&M remains in the bait cup, serving as a backup lure.
M&M’s also give base the base lure in traps some protection from the elements. M&M’s only allow moisture to reach a small amount of the base lure and humid air can only reach a small amount of it, so mold is a minor issue. M&M’s are quite dry, so they go moldy slowly, and rodents will eat their way through the shell. Instead of a base lure going stale in hot, dry weather, M&M’s keep the base lure underneath them fresh.
With a whole or partially eaten M&M inside a bait cup, it will take a rat longer to eat what’s in the bait cup than a soft lure on its own. Instead of only using its tongue, a rat has to use its teeth to crack the shell and nibble on the chocolate, which may cause enough vibrations to fire a trap. If a rat wants to take an M&M to its nest, or eat it away from the trap, they have to use their jaws and/or paws to do so. This also creates more movement inside a trap, increasing the chances of it firing.
Thus far, the mice here haven’t managed to eat an entire M&M by the time a rat finds a trap and ants have only eaten a base lure once. Before I started using marbles and M&M’s, the majority of my snap traps would be licked clean by mice before rats showed up, so I was feeding lots of mice and killing very few rats. Using marbles or M&M’s as “obstruction lures”, instead of exposed lures, my rat kills per trap have increased significantly.
I haven’t tried it yet, but it’s possible that M&M’s could be effective if they’re pressed onto PB on the lure pad of a Victor. A rat will have to break the shell of the M&M to eat the chocolate, which should create enough pressure to fire a trap, and it should be difficult for a rat to remove an M&M from a sticky base lure with its jaws or paws. I would expect the number of mice killed by Victors using M&M’s as lures would be way higher than normal.
I highly recommend experimenting with M&M’s. It’s an easy technique to use and a small bag of plain M&M’s goes a long way, so it’s a cheap experiment to run. If you do try M&M’s, please share your results, good or bad.
Cheers.
Note: Because chocolate is harmful to some animals, please only use M&M’s inside tunnels that birds and pets can’t access.