Could Great Tits have abandoned nest?

Hi, we had a pair of great tits build a nest in our letterbox which is built into our front fence. I think the chicks may have hatched at the start of the week, but I haven't seen any activity in the last day. Cats have been around and I'm worried they have scared the parents off or worse. Possible us going in and out of the house may have upset them too. Not sure what to do.

Thanks. 

  • Do you have a time scale from seeing when they first started using the letterbox? Chicks tend to get noisier and more demanding for food the closer they get to fledging so if your previously noisy nest has suddenly gone quiet it could be that there are small GTs hidden around the garden. There is really not much else to suggest as to open the letterbox to look could cause more harm and would be regarded as interfering
  • Thanks for the reply. One has just returned 5 minutes ago! But it's not looking like there's a lot of activity, unless maybe not all eggs have hatched yet.
    I've put a couple or rose bushes directly under the box to stop the cats stretching up, but they are still about and a huge risk. I don't feel like this nest is going to be a success. I'm not sure how to help them.