I have a 3 year old siamese mix neutered boy who is very docile and sweet-tempered. I thought he was lonely so I got him a little siamese sister and they get along great. But every night without fail, he goes to the sliding doors of my closet (they are full length mirrors as well as sliding doors) and starts crying dolefully while pawing the edges of the doors... it makes the loudest clanging sound! Nothing stops him from doing this. I have tried water guns, clapping loudly... he will leave temporarily then come back five minutes later when I'm finally falling asleep.
Any ideas as to why he's doing this? It is incredibly frustrating.