Help with yowling

I'm not sure if this is the right place to post, but it IS keeping me awake!

I just took in a very friendly stray that the vet says is about a year old and pretty healthy, but this cat yowls almost all night. My husband is about to toss him back outside. The only thing that stops him is my 13 year old daughter, who is the biggest cat fan in the house, and the fact that he's already cost us almost two hundred dollars in vet bills. (He'd been in a fight and had fleas that needed treatment.) I've been putting him in the basement just to get some sleep, but that's not a permanent solution, because when he's down there, my older cat sits at the door to the basement and bangs it with his paw trying to let the newcomer out, which is also noisy. I have an appointment for the new cat to be spayed December 15th. Do you guys think that will help?

If the newbie is a female - she could well be in heat, hence the yowling. Be sure to keep her indoors, she might want to try to dart outside.

M male cat Nemo howls ALL NIGHT LONG!!!we have no idea why and it drives us nuts!! he is perfectly healthy!vet says he just likes to tell us his problems!!lol

Yes...it will help but it is also essential that your daughter or someone play with Nemo daily.

Both of my cats seem to build up energy. If I neglect their play time, they go nuts, howl, run...krazy Kat stuff.
Hopefully other members will have more feedback for you soon.

When Harley came here about a month ago, she had a habit of yowling at night, the second I went to bed. She's a very vocal cat to begin with, but listening to her howl and cry just because I left the room to go to bed was both pitiful and annoying at the same time.

It's pretty much stopped now; I always make sure that I play with her for quite a while (until she's either tired or disinterested) before I go to bed at night, and if she does try yowling for attention after I get in bed, I ignore her. Playing is very important; I do it several times a day, whenever I think she's interested - not just at night.

Perhaps the cat wants to go outside? Cat's are usually nocturnal when outdoors.