Trapping in the winter ?

I had 2 new males show up at my house last night (a red/white long hair and a tuxedo). I think they have been hanging in the vacinity lately as my resident ferals have been acting very weary the last few days. I heard growling by the front porch last night and turned on the light to investigate - they were face to face, hissing/posturing with each other, and when I tapped the door they both hightailed it in opposite directions (and yes I'm confused - there are no unneutered females here so not sure what drew them in).

So assuming that they come back, I will trap and neuter both of them. Since I haven't trapped in the winter before (the new ones usually show up in the spring), and I will assume that they will appear late at night (with no chance to get them vet until the morning), any tips on how to keep them warm overnight?

I was planning on setting the trap in the evening (after sunset) and keeping an eye out for it to trip. I hate overnighting them in the cage, but it probably wouldn't be a good idea to bring them into the house. I have the underground shelter (stays relatively warm) to put them in - it has a door thata closes and is entirely out of the wind. I was thinking of putting straw down on the floor (under the cage), blankets over the top, and perhaps some feliway spray for the cage (once the blanket is over the top to hold the feliway in).

Any other ideas?

Thanks Katie! So, I guess the suggestion is to wait until it warms up or get them inside before and after the neuter. I'll have to see if we have a string of warm days coming - it was in the 50's here over the weekend and our winters often have warm spells. Puppy is coming in after the first of the year so will lose my feral quarantine room for a while.

Momofmany, did you have any luck trapping them during the warm spell?

Also, you might ask whether your vet would be willing to keep them overnight both before and after the neutering. One of my vets has a huge dog crate he will put my ferals in if necessary. He doesn't even charge extra when I need to do this because the cat isn't being kept in the regular kennel area.

I only saw one of them (about a quarter mile down the road) before I left for Christmas and no sign of them today. My vet will overnight them for me if they come back and I can catch them. At least I think I know the general direction that one of them lives in, so can set the trap further away if necessary.