Bart sprayed the door. Why?

This is a relay message, since I'm away at school, my Dad's living with the three cats.
One of them is Bart,

Yesterday, my Dad came home from work, Bart and Lucy ran up to say hi, Dad picked up Lucy like he always does, and Bart immediatly ran up and sprayed the door. He didn't pee like in the litterbox, he sprayed.
Nothing my Dad did was out of the ordinary, he hadn't let the cats outside for a day or so before. He usually lets them out on the weekend and for a bit after he gets home and since Bart was abandoned in the middle of February he usually stops going outside this time of year anyway.

Bart's 7 or 8, we rescued him when he was (an estimated) 2 years old. He was neutered then. He's never done anything like this before, never had any serious problems with the other cats, just normal politics.

My only idea was that a strange male cat had been coming around the neighbourhood. But we've had strange cats around before and he usually tried to fight with them.

Bart doesn't like being picked up and doesn't really invite petting. He usually just sits on my Dad after dinner and sleeps on his head.

My dad's friend has a female intact cat, if he had petted that female before coming home, would Bart have reacted to that in some way?

Thanks in advance for any ideas...

inkl

Its very possible that the unspayed female triggered the reaction. If he was not neutered till 2 yrs old, he probably sired kittens and does remember.

I know my first cat, Mitten was probably not neutered till over a year or so. He "bred" my RB female to show her what would happen. Didn't do it more then one time and never sprayed, but he went thru everything a tomcat would do (neck hold, etc.).

GoldenKitty45 is right and so are you. It could be that lady cat - or it could be a stranger in town -- or both! Cleanup is easy with enzymatic cleaners like Nature's Miracle Just For Cats, which actually destroys the bacteria which cause the odor and dissuade Bart from re-marking. GOOD LUCK! Love and patience will win the day.

I'm assuming that he smelled the female, too, and is just marking his territory. Cats are very territorial.. I woudn't worry about it, unless he starts spraying on a regular basis..

~KK~