Have you heard any House Wrens singing? I know you are an experienced birder and have all the proper guards in place, so my only guess would be perhaps a HOWR stealing their eggs? You just haven't had very good luck with the Blues. You must be so frustrated.

It wouldn't have been the spooker that scared them. More likely either something happened to the female or like Kendra said, something got the eggs. Can you see this box from your house at all, do you know if the Blues are going in it anymore? I would monitor it closely and see if they are still going in or not. The Blues you saw could have been a different pair, or a different female and they are looking for a different box if the first one failed.

Good luck!
Donna

Kendra the last time I heard A HOWR was a few weeks ago. Since then nothing. Plus my boxes are in a large field that have never had HOWR using them. The site is so open the chances of another natural cavity being nearby is VERY slim.

Donna I can just barely see it from my house. It is in my neighbor's field. My yard is open enough but is too close to woods and would just have problems with HOWR. (Which yes, used to cause me problems)

I also saw a Cooper's hawk fly right through and by the boxes today. Another suspect. I think you have it right on the money Donna. And the nest appears the same and undisturbed so I highly doubt they layed more. Again, I never actually saw a 3rd, 4th, or 5th egg. I was away on a trip. So predation is very unlikely.

Could just be a young female and that's all for this clutch. I would leave things as they are and see what happens.

Really hard to know. Lisa, I've never head of bluebirds having a clutch of 2. And plus, there's no incubating going on.

I was at the 2nd box at the 2nd pair and Mr and Mrs blue flew towards me a bit. Then later on I saw Mrs blue at the box with the 2 eggs. She didn't go in. But they've added to the nest. The eggs appear deeper in. Maybe they're gonna cover them and lay new ones or start another nest at the other box? I'm gonna leave the eggs but I took the spooker down.

It sounds like this is a new female to me. A new female would build another nest over the top of an old one, as they wouldn't reuse another birds nest. Sounds like what is happening. Hopefully this one can be successful for you!!

Donna

I have had a clutch of just 2. I am still waiting for a first egg......WAY late this year!

There's been little additions to the nest and a little activity at the other box. My guess is the female new female hasn't decided which box.

You live in Michigan right, Lisa? Because I don't know about there but here I'd say they're on schedule because if you remember we had an early, very warm spring last year. The 1st week of April last year was all 80's. At that time I had nest building. It didn't start till the end of April this year.

The blues have been around every day now and are very active so now it's just a matter of what box they're gonna use. TRES are doing good. 1 clutch of 4 eggs
-Tim-

More news for my blues.

They've stayed around all the time except yesterday I didn't see them.

Today the nest has a new lining and the old eggs are buried underneath. When I approached the box the Male and Female bluebird were flying back and forth. This was before I opened the box, So I knew something was up.

So most likely the other female was lost during egg laying. Funny every time I leave, even for just a few days, something goes wrong.

Next week's weather doesn't look good. It's been around 80 and now it's getting humid. By Monday we drop to 50's for highs!