Oh I'm so sorry. 4 things come to mind. 1. House Sparrows but it sounds like you could not tell if they had been pecked. 2. Poisoned by pesticides from one of your "perfect lawn neighbors". 3. Parasites, blowfly etc. 4. Is there a wasps nest or ants in there? Too bad you didn't do a little detective work before you buried them. It would have helped you fix whatever happened. One other thought, was your weather cold and raining for a few days? You should be able to bleach the box and rinse it well then let dry. Here is a helpful site. www.sialis.org. Lots of good BB info! Good luck and I hope they try again!

Thanks for your reply, Lisa. I could not tell if they had been pecked, because they were too far gone. There were ants in the nest box on and off (really bad before and during egg laying, but I got them all out, I thought), but I didn't see any today. No wasps. As for rain: we have had nearly 20" of rain here in the last 5 weeks, and it has been cool during that time, too (night lows around 38 for a stretch there, probably around the time the chicks died). I didn't know that could affect them.

I will try bleaching the box. I may also switch it with the box on the other end of the yard that the house wrens keep filling with sticks.

Oh, how awful. You must have felt so sad to see such a thing. Wow. That sure wasn't what you expected. Like Lisa said, you can bleach and reuse the box. You know for sure that you had some ants in there, so that would be an issue to address for sure. Check out what the sialis site recommends. I suppose this is a good arguement for monitoring our boxes. Next time you get a nest, keep written records of when the eggs are laid. Incubation begins when the last egg is laid. That way, you will know for sure where your nestlings are in the process, and can keep a good check on them until it isn't safe to look anymore. Sialis says not to monitor after the babies are 12-14 days old. I'm so sorry this happened to you, but don't despair or give up. There is still lots of time to get more Blues and have a successful fledging. :o) Angie

Here is a link that might be useful: Ants in nestbox/Sialis

Thanks, Angie. I will take better notes next time. I looked at them every few days until their eyes were open and they had feathers with bluebird colors (i.e. around 14 days old), using Sialis as a guide. We then saw them looking out the nest cavity and being fed by both the male and female over the next few days, and then... nothing.

Thanks for the encouragement. I won't give up, but I do want to understand what likely went wrong so I can intervene in the future to avoid something like this. For now, I am going with the cold/wet weather as a cause, either due to hypothermia or/and starvation (or earthworms). The ants were not the biting variety, but did seem to annoy the female during egg laying and incubating... Who knows. Next time I will try grease or something.

I sure hope that doesn't happen to you again. Let's stay positive and assume that the next time will go perfectly. Sometimes, there is not a thing we could have done to change the bad outcome. I feel that part of being a good steward is realizing and accepting that as fact. Then, we just press on and do the best that we can for them. Good luck, and let us know..Angie

Thanks, Angie. We did successfully fledge 4 out of this box last year from a later clutch (she didn't build until mid-June), so I know it's possible. The weather should be better for it now. I will bleach, dry, and try again.

if you have hosps did you have a spooker on the box??? It is definitely a must and saves many eggs, chicks and adults!!!
Cathy

I suppose the another possibility is that one or both parents were killed and the chicks perished from chill and starvation?