I have a single BB Box on a 5' post.  It is in the open about 20' from nearest tree, 15' from grape arbor and 75-100+ from heavy woods.
The past two years, I have had 2-3 broods of 3.  The box has been cleaned since the last brood left.  There was a single egg still in the nest after the babies flew away.
I live in E. Central Alabama and it is now Oct. 10th.

Twice this week, I have had swarms of both male and female BB's around the box.  Usually 6+ birds.  They land on the post, top of the box and on the hole. And in the trees nearby.  Both sexes will sit and look into yhe hole for 10-15 seconds, fly away nearby and another will follow suit.
What are they doing?scoping out the box for the spring brood?

I have not seen this behavior in the past.

Thank you

Hi Roger. The unhatched egg is not unusual. Sometimes as many as 15% of eggs are not fertilized.

Flocks around your box also is a common ocurrence depending on the weather as many of the northern birds are migrating south. Usually they will move on, and as they pass through it is normal for them to check out boxes.

If you will send your mailing address to me at I will end you a copy of my free bluebird book. Happy birding.

PS - See page 19 for why you should have more than one box.


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Bluebird Bob Walshaw


Questions about setting up and monitoring Eastern Bluebird houses. This includes where and how to put up houses, trouble shooting, fighting predators, especially the killer house sparrows and helping other small cavity nesters such as Chickadees, Titmice, Carolina Wrens, etc. Send mailing address to me at for a free 20 page Bluebird book.


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