Bluebird fledglings gone

This is my first year with bluebirds. My first couple built a nest in a nestbox and laid 4 eggs. Only three hatched. When they were ready to fledge I had to be out of town for 4 days, I didn't want to miss them leaving but I had no choice. I know the neighbors cat got one fledging, it takes all it's trophies to her doorstep. But when I returned, the housesitter said she hadn't seen any bluebirds at all. After one day of me getting home, the parents returned and started building a second nest. But I have not seen the other two fledglings. The parents don't seem to be taking food anywhere special, that I have noticed, they stay in my backyard. Is it possible the two young are still hiding in the trees somewhere? It has been approx. 10 days since they left the nest. Or should I assume something got them too?

No way of knowing. If they are still alive, I would guess that they will visit your yard with the parents at some point. My neighbors understand that their cats stalking birds in my yard causes them a great deal of stress. I no longer have that problem.

I am a bird watcher and I also have cats. The primary thing I have done to protect my avian friends involves feeder placement. The fundamental rule is that the feeder must be away from bushes, where cats can lurk. Feeder design can also be helpful for protection. A broad tray underneath can block the jump of a lurking cat. Cages for small birds feeding are obviously protective. The rock bottom line is that thoughtful placement and design of your feeders is the best defense against natural predators.

Thanks for the replies. My nest box is away from anything that a cat can jump from and it has a large guard on the pole. I believe the cat may have gotten the one on the ground. It didn't get into the nest box. And the feeder is on my upper deck. I am just hoping the other two young are out in the trees somewhere. The parents have been disappearing for an hour or so in the last 2 days. Hopefully the second brood will have better luck.

Thanks again.