There has been a cat wandering about my block of flats for a few months now, especially when I took my own cat for walks on her leash. However, the cat has remained under my window, sometimes for full days and nights. I began feeding it, thinking it was a stray (it once ate a whole mouse outside my window), and eventually we built a shelter for it as winter set in. To ensure that the cat was a stray, I attached a collar with my phone number and a message to his neck, yet there was no reply and the collar dissapeared after a few days. The cat has always been well fed and groomed, but I am well aware that that could be due to the generosity of me and my neighbours. At the moment, it is very cold outside, and despite the shelter and feeding, the cat remains cold and wet. I have been gradually introducing him to my home, and plan to take him in, check for microchips and perhaps keep him. However, I am still not sure whether this is a good idea, and whether the cat really is a stray. He is quite friendly, neutered, and responds well to attention, stroking and grooming, and has become quite attached to my family. I am also slightly worried on the impact on my other cat, who seems to be fairly unfriendly, if not outright aggressive, to him (though the feeling is mutual) though this may be due to a competition for territory. I would also appreciate advice on how to catch him, as he is usually outside.