Dear Critter Corner: Recently I have noticed that my 5-year-old male cat has been inconsistently using the litterbox, resulting in a couple of accidents around the house. He has never had issues with this in the past, and additionally I have noticed that he has been marking by my patio door over the past few weeks. A very friendly stray female cat and her kittens have been frequenting our backyard since the beginning of last month, and I have set up a food station and temporary shelter for them to use. I have asked around my neighborhood and no one has claimed these cats, and I suspect that the cats were indoor cats at one point. My cat is not particularly fond of these other cats and does get quite worked up by the glass door when he can see them in the yard.
Cats are naturally territorial animals, and based on your observations, I believe that it is possible that the litterbox issue and marking around your patio door may be related to the new visitors that have been staying in your backyard. It is very important that your cat feels safe and secure when in his home, so providing plenty of spaces that he would be able to hide and perch upon is important. I would then suggest finding all the areas where he has had accidents and deep cleaning each individual spot. Normal cleaning agents are not the most effective when trying to sanitize the soiled area, so I would recommend using a pet-safe enzyme cleaner to help break down any of the residual urine that is undetectable to us.
I would suggest asking a local rescue or shelter to see if they have space for potentially taking on the cats residing in your backyard. This would allow them to receive all medical care they need before being adopted into their forever homes. This will not only help reduce your cat’s stress but also provide a permanent home to the stray cats living in your neighborhood.