Cat middening is territorial marking behavior just like spraying urine horizontally onto objects such fence posts etc. (see above). Obviously the cat is defecating when middening so that that function is being served but the primary function is to mark territory both visually and through smell. It is a very obvious statement, more so than spraying urine.
My cat has never defecated or sprayed as a way to mark territory although outside my living room window where several cats from different homes wander they sometimes mark and remark the same spot in a competition to claim the territory.
Wild cats midden often, sometimes using crossroads on their trails to create a “toilet” where they mark territory with feces. Wild cats also scent mark with their cheeks and visually mark with their claws. I believe the word “midenning” is used exclusively for domestic cats but I don’t mind being corrected.
Male, dominant feral cats and semi-feral cats living in a group might deposit feces without covering it up as a way of sending a message of his status whereas a more subservient cat will cover his feces. The dominant feral cat might midden at a high relevant point within his territory. Unneutered domestic cats do it as well at places in dispute with a neighboring cat.
Therefore for the domestic cat, middening is not misdirected toilet behavior, it is a very specific act of using feces placed in the open at a specifically chosen site to make a statement: the right of occupancy or the right to use an area or “trail”.
I would say it is quite rare. Spraying is more common. A nervous cat who is subjected to change causing emotional upset or challenge may do it.
Middening is an alternative to spraying urine for the domestic cat. Apparently it is more difficult to resolve than spraying because it signifies both a bigger reaction to the challenge and that the cat is more upset.
The domestic cat will usually midden at doorways and walkways because these are areas used by the family and where challenging and unusual smells and activity is likely to take place.
Sometimes a cat will choose a more “public” and obvious place such in the middle of a room or on a bed. Other places might include:
- top of a fridge
- top of chairs
- on personal items of the family such as headphones
- other electrical equipment
As middening is normal behavior and is not uncommonly caused by environmental stresses created by the cat’s owner it is beholden upon the owner to treat the “problem” delicately and avoid punishment which will only serve to exacerbate things.
Technically middening probably falls under that euphemism “inappropriate elimination“, which means that people find it inappropriate but not the cat.
The reason for this form of behavior needs to assessed and removed. It may be caused by moving home or perhaps stray cats wondering into the home. We know that moving home is a classic stressor and it removes the cat from his/her home range so he’ll have to reestablish one.
Cat owners are probably unaware of how often it might occur outside if their cat is an indoor/outdoor cat living in a place where there is competition from other outdoor cats.
Sources: myself and So Cats Need Shrinks?