I've seen both of the new cats at night. One or the other is probably the one who injured Alger's leg a couple of weeks ago. Early yesterday morning I saw Alger on the back porch, but it was a bit too early to go out and feed him so I waited, and then about fifteen minutes later the black and white cat was out there and Alger was gone. I ran the tom cat off, but haven't seen Alger since. I haven't seen his two litter-mates for three days now, and it's been four days since all three of them were out there together. I'll miss those kitties if they stop coming around.
Keeping constant watch on the yard isn't possible. When the food vanishes I don't know if it's the new cats who ate it or if the kittens have crept back in long enough for a snack. I guess this was bound to happen eventually. There are a lot of cats around here, and the weakest ones get pushed out of the best feeding spots. I might stop putting food out unless I actually see one of my feral cats out there waiting. They might be too skittish to hang around long enough for me to discover them, though. No really good options are available as long as the new tom cats are around.