Nov 12, 2010

Old Finnish Mouse Traps

As winter approaches many rural house-owners have to deal with familiar infliction; mice.
Rodents seek shelter in the warm houses and obviously give cause for some real concern as they pose a considerable health risk. It's fairly today easy to go to the local hardware-store or the supermarket to pick up some traps and poison, but not to far back in time in Finland buying traps to fend of the mice was not an real option. Cats were put to the task and they kept the rodents at bay. But cats were not allowed to roam everywhere such as indoors in the pantry and other measures had to be taken to secure the valuable food supply.
Image 1. Wood mouse (Apodemus sylvaticus), these guys visit us every year.

Less than a century ago people had to make their own mice-traps, which in many cases are scaled down models of larger traps used for hunting small game. The mechanism of these small traps is virtually identical with the mechanism on larger traps. These types of traps where commonly called nakki. Linguistic studies show that this type of traps are truly ancient among Fenno-Ugric peoples; the Komi and the Udmurt call it nal´k, the Khanty and the Mansi know it as n’al’. In Finland these old traps originally used for hunting were redesigned and adapted to the needs of the agrarian lifestyle.
Image 2.The Kuhmois trap.
These three traps are all constructed without using a single nail. The first trap (image 2) originated from Kuhmois and is very simple in design. Is consists of two boards, some string, a small and thin piece of wood, an arched shoot or a twig and a small pin. The boards are sewed together at one end. A string is attached to the trigger pin and the other end of the string is attached to the arch, the length of the string is adjusted so the pin is able too ”hook” to the small piece of wood that works as the trigger release. The end of the pin fits in to a notch int the trigger release. The weight of the board presses down on the trigger pin, and as the pin is attached to a string and is in a slant outward position the pin wants to flip around the board. The pin is held in place by the notch in the trigger release (image 3). As mice go for the bait on the trigger release the press it down and thus releasing the pin and bringing down the board on themselves. The efficiency of this trap is an issue if just relying on the weight of the board. In order for this trap to work properly a weight should be added on top of the board such a flat piece of rock or brick.
Image 3. Detail of the trigger mechanism on the Kuhmois trap.

The second trap is a model from Korpilahti (image 4) and is virtually identical to the first, other than the frame forms a box that traps the prey alive. The trigger release has to pass through a whole at the end of the board and that hole can´t be made too big since the mice might be able to escape. Adolescent mice can squeeze through a hole the size of your fingertips.
Image 4. The Korpilahti trap.
The third trap from Vammala is the most advanced model as it has a primitive spring mechanism (image 5). The frame is made out of a single piece of carved wood (image 6) and has to fit the spring cable, which traditionally was made out of horsehair. The spring cable is wrapped around the board which has grooves in one end. The spring cable is held in place by pins that can be rotated to increase the strenght of the trap. This trigger mechanism is an ingenious adaptation of the two former ones. This type of compact traps where used in pantry's and behind furniture inside the houses. 
Image 5. The Vammala trap.
I have tested all of these three traps and discovered that they all perform well, although hygienic factors have to be taken in to account as sterilizing wooden traps is virtually impossible. They are however fun to build and have and kids enjoy playing with them. Happy trapping!
Image 6. The Vammala trap under construction.

Image 7. All three traps ready for action.

An article of the same subject has previously been published in Swedish language in the Finnish Magazine ”Trapper” Issue 4 of 2009.

Further Readings 
Sirelius, U.T. 1919. Suomen kansanomaista kulttuuria. Esineellisen kansatieteen tuloksia I. Otava. Helsinki 1919.

Photo Credits

Image 1-7: Marcus Lepola

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