We have small brown droppings near food and open packages of popcorn and flaxseeds. Droppings are 1/4″ long and narrow. Have Weitech Transonic CIX device going for 2 days and still new signs of them. Put out rat/mice poison and all eaten last night. Do you think it’s rats? Nesting this time of year?
Why do they come inside? Best way to get rid of them? Carry disease? Best way to store food – they are chewing through plastic packages – new plastic yeast package, plastic prune package, popcorn in plastic. No smells and sometimes double plastic. What do they eat? Best way to protect your extra food supplies? This is in concrete basement at ground level in country. No water that I know of.
It’s a little tricky to categorize droppings of that size as belonging to either mice or rats, since a mouse dropping is usually about the size of a grain of rice and a rat dropping is usually about 2/5″ long and narrow, but It sounds like you are describing rats, not mice. While it’s a fact that black rats tend to like roofs and dry places and brown (Norway) rats tend to like basements and damp places, a brown rat will still come into a basement for food even if it has to leave the basement for water. Luckily, that’s how you may be able to trap them.
For part of your bait, place a bowl of water in a Havahart trap, well secured with weight so a rat can’t turn it over and simply drink the spill. The purpose of using a Havahart trap isn’t necessarily that you have any love for the rats. It’s simply a better way to use fluid as bait.
In addition to the little bowl of water you put out for your rodent trespassers, put out a food bait, too. Here it is best to use foods that they are already accustomed to eating, in your case, flaxseed and popcorn. Rats are wary creatures, and they will always eat a familiar food in preference to an unfamiliar food. If they have been eating prunes, use prunes for bait.
If you want to use snap traps, be sure to place them along walls, not in the middle of your basement floor. Not only will this reduce the risk of a rat trap snapping on your own bare toe, but also the rats are more likely to encounter them if they are placed along a way. Even better, construct a “tunnel” over the box with a cardboard box or a shoe box with both ends open or buy a rat zapper. It isn’t necessary to put your Havahart trap in a cardboard covering.
Poison isn’t a good idea in the same room you use for food storage. You may need to protect your food in glass or Tupperware. Plastic wrap is not enough to deter a hungry rat!