Today two of my apartment doors had been opened, and were empty. One dead male on the porch of the house. Nothing in any of the nests, and no sign of any birds. I'm in mourning.
It could also have been an owl. At my site, I had one door partially opened and later had most of my nests destroyed by an owl, this all took place after a raccoon was clever enough to get by one of my pole guards....
Went to the doctor one day and when they got back a predator had opened the housing on one side and taken all the babies. A neighbor said they saw a large bird on the house. Took care of the problem on the other side of the house by wiring the entrances down.
Sorry to hear but at least you can take care of this for next year.
Thank you all. I don't know what kind of predator it was. I assumed a raccoon since some doors were opened, but maybe an owl is able to open doors, too. Yes, the only thing I can do now is prepare better for next year: wire the doors shut and buy predator guards. I just hope some survivors will come back.