Simple homemade mouse trap
Mice have entered my mom's apartment through (presumably) pipes in the central heating system. It's not a regular problem but it's happened several times now. There's a heating unit in each bedroom and the living room, and we've taped over the floor-level openings of the units since discovering they serve as mouse portals. But tape adhesive loosens with age and we don't check them constantly. We haven't used poison in my mom's apartment because we don't want poison spread around the apartment nor any hidden decomposing mouse corpses. Traditional snap traps, humane box traps, and smaller mouse-sized glue traps have been ineffective. The larger rat-sized glue traps have proven to be my most effective tool for catching mice.
I caught the 1st mouse in a 20-pound rice bag. The rice bag was stored upright, in a plastic bag and box, on the floor of the kitchen, with the bag opening on top folded down. Yet we heard the mouse rustling inside the bag and saw mouse poop on the rice within the bag. Placing snap, humane, and glue traps around the rice bag didn't work - the mouse avoided the traps and got into the rice. After several days, I placed a large glue trap within the bag, on the rice, and folded down the top of the bag as usual. That night, the mouse was caught on the glue trap in the bag. We now use a large black binder clip to seal the rice bags.
I caught the 2nd mouse in the opening of the heating unit in my mom's bedroom. I heard suspicious noises coming from the heating unit and guessed mice were using it to enter and leave the room. I placed glue traps on the floor where I estimated mice would drop from the unit. It worked. A mouse was caught either coming or going, but my guess is it dropped onto the trap. After that, we sealed the openings on the bedroom heating units.
I caught the 3rd mouse in the living room next to the television. Mice will sprint across a room to go from point A to point B, but typically travel along the walls. The TV is against the wall next to the heating unit, which creates a blind turn. A mouse-sized glue trap at the elbow of the turn failed to catch the mouse, but I knew the mouse was using that path. After a few days, I placed a larger rat-sized glue trap next to the smaller trap around the blind turn and against the front of the heating unit. I actually witnessed the mouse peek out from behind the TV, streak over the smaller glue trap, and get caught in the middle of the larger glue trap.
Last night, I caught the 4th mouse in a bucket modified into a sort of camouflaged punji stick pit. The mouse had entered from the living room heating unit where the tape over the opening had loosened. I set out glue traps, baited with chocolate, rice, cashews, or chicken meat, in the living room and kitchen, including a repeat of the TV-heating unit elbow trap, without success. I found the linked mouse trap instructions on google yesterday. I modified the trap because my mom doesn't have the 20-inch-plus high container that the blog recommends, only a 10-inch high bucket. I decided to place glue traps at the bottom of the bucket so an acrobatic mouse couldn't climb or jump out. I trimmed the plastic borders so they would fit together better in the bucket and form a more-or-less contiguous glue surface. Rather than an unbalanced toilet paper roll, I covered the bucket with a paper towel sheet. The paper towel hid the glue traps from the mouse. I taped one edge to the bucket so the sheet wouldn't fall in with the mouse and possibly save it from the glue traps. I taped two thin plastic strips to the bucket on the opposite side to barely hold up the trap side of the paper towel. I baited the trap with a piece of cooked pork on the center of the paper towel because mice like meat (see youtube videos of cannibal mice), which I hoped is rare enough in a typical mouse's diet to overcome this mouse's hitherto trap-avoiding judgement. My mom had spotted the mouse in the kitchen so I placed the bucket in the same location of the rice bag. The 1st mouse I caught had entered through the top of the taller rice bag so I thought this mouse would find a way onto the shorter bucket. A few hours later, I noticed one corner of the paper towel was down, though the paper towel was still up and the pork was untouched. The mouse pictured above was caught.
7/14/11 update: There's at least one more mouse in the apartment, and it's not falling for the bucket trap. Smart. 12/22/11 update: For about a month, the mouse ran around the apartment with seeming impunity, too often in plain sight. Tried a growing number of multiple types of homemade traps of increasing complexity and different baits with placements spread around the apartment; all failed. Finally spotted the mouse running behind a plastic bag of magazines that was against a wall and recalled seeing the mouse around that general area more than other places. Placed a simple glue trap at juncture of wall and bag. The mouse ran onto the trap and was caught. Turns out the mouse had gotten inside the plastic bag, shredded the magazines, and made itself a den. For all the mouse's cunning and my creativity making traps and placing them, the mouse was finally caught with a simple trap placed inside his pattern of travel. The key was identifying the mouse's habit. The lesson learned is that there is a point on a mouse's route to safe harbor (escape or den) where habit, with perhaps an irresistable sense of imminent safety, overwhelms its sense of caution.
Mice, at least savvy NYC mice, will avoid traps they can see and possibly touch, regardless of the bait. Simply placing traps on the mouse's known routes of travel doesn't work. If a mouse can directly associate bait with a trap, it won't take the bait. The trap has to be camouflaged somehow. Mice don't seem to sniff out visually hidden traps, though.
Use larger rat-sized glue traps. Traditional snap traps, humane box traps, and smaller mouse-sized glue traps are largely useless for catching mice, at least when they're used in the open.
The keys to catching a mouse are knowing the mouse's behavior to use against it and deception. Mice, while cautious, will develop patterns. The 1st two mice were caught because I identified where they were dropping blind and placed glue traps on their landing spots. The 3rd mouse was caught because it knew it could go over the smaller glue trap it saw, but was tricked by the adjoining larger glue trap the mouse didn't know was around the blind turn. The 4th mouse was the only one I induced to go someplace different than its pattern, although I drew upon a previous mouse's pattern in order to catch it.
There is a point on a mouse's route to safe harbor (escape or den) where habit overwhelms its sense of caution. That's the point where a mouse finds the sense of imminent safety irresistable and is prone to make a straight line break for safe harbor. Place a trap at the spot on the mouse's path to safe harbor where a smart mouse gets stupid and abandons caution.
A blurry sprinting mouse looks bigger than its actual size. I thought the above pictured mouse was twice as big as it turned out to be.
Mice will run across rooms occupied by people during the day or lit at night.
A caught mouse will empty its bowels and struggle hard to free itself.
Mice can squeeze through small openings. Maintenance nailed a chicken wire barrier over the living room heating unit opening, but chicken wire warps and bends. I recommend using tape instead. Use strong tape such as duct tape. But even strong tape loosens eventually and needs to be rechecked.