Back in my own backyard again: The bluebird box is silent. Madame & Sir Blue have gone missing. I know not what ill befell their family in my two week absence, but it most certainly was disaster. I suspect house wrens were involved. The time was not right for the bluebird nestlings to have fledged, so they could only have come to a bad end.
Here's what I do know about their timeline, some by research, some by my own observations, and some by the eye-witness reports my husband gave me via phone while I was at the bay.
Nesting Facts: In Georgia, bluebirds begin nesting behaviors in early-March. After mating, the female lays one egg a day for 4-6 days, usually by late-March. Incubation period: 13-15 days. Nestling period: 15-20 days. Two to three broods per season.
Observed timeline of this particular pair of bluebirds:
Mar 8: First sighting of male bluebird in backyard and investigating birdhouse
Mar 16: First sighting of female in and around birdhouse and birdfeeder.
Mar 19: First sign of courtship on dogwood branch
Mar 23: Observed both birds in and out of house. Female getting fatter.
Mar 28-Apr 4: Egg laying week. Fat female got thin again by end of week. Both birds seen often at feeder and in and out of birdhouse. (feeder kept filled with shelled sunflower seeds)
Apr 6-11: Now thin female seldom seen, but occasionally perched on branch near doorway of house. Male came and went from house often. She was likely egg-sitting and being fed by him.
Apr 12: More of same. I left for bay, asked Moe to watch and report.
Apr 13-18: Moe sees only the male coming and going from house.
Apr 19: Moe reports seeing both male and female flying and perching in tandem around the yard. Hatching day? Unable to see or hear anything in house. Hatchlings too small to be audible?
Apr 20: Bingo! Moe hears tiny nestling chirps inside house. Very soft chirps.
Apr 21-22: No observations made
Apr 23: No sounds from house. Moe observed a small brown house wren in and out of the house several times.
Apr 24-26: No sounds, no activity of any kind, either bluebird or wren. I returned home on 26th.
Apr 27-30: No activity. Moe confirmed that house wren was seen only that one day, on 23rd.
May 1: Today, in fear and trepidation, we opened the house to see what we could see. Nest was empty but clean, soft, fresh-looking---no sign of nestlings, no sign of shells, no sign of struggle. BUT, we observed male bluebird several times on various perches around the yard, offering hope that he may try again. Where is the female? Do they feel the grief that I feel on their behalf? dkm