- This topic has 5 replies, 3 voices, and was last updated 5 hours, 21 minutes ago by
.
-
Posts
-
So we had a strange thing happen with a BB nest. For about a week we observed a female BB inside a tree mounted box. The box has been up several years and this was the first time we saw any activity in it of any cavity nesting species.
She would sit in the box over the course of the week, occasionally I would see the male appear at the box as well.
So for the past several days we noticed no activity at the nest. It was pretty hot during this time, getting well into the 90’s several days, though the box is well shaded by trees.
So after dinner just moments ago, I walked out to it with a flashlight just to peek inside. Not sure what I would find, but I knew something was amiss. When I got a good look I could see it was empty. I opened the front door and there was nothing but nest material, no poops or little feathers to indicate any chicks had ever been there. The box was literally like the day I put it up, except a BB had built up a nest in it.
My question to the experts is, what could have happened? Me and the wife are speculating everything from she tried to lay but never did, to a snake ate her eggs, to maybe she laid them but they were all non-viable and she took them out of the nest.
Has anyone had anything like this happen before and any theories? Thanks. Pic (if it works) is a shot of the nest from our back porch with the mom sitting there as she did over the course of week.
I’m not an expert but I have some experience in my four seasons of bluebird trail monitoring. I have averaged two dozen boxes each season.
Bluebirds are very clean parents. When I clean out a box after fledging sometimes the only evidence of success is a little extra bird dander mixed in with the nest materials. I usually dissect the old nest to check for blow fly larva or other pests. This year there has been no blow fly larva. My first season it was very common to see the worms buried in the bottom of the nest. That’s when I learned how important it is to clean out old nests and dispose of the material far away from the box. IF the blow flies establish themselves and a second brood uses the nest the larva could kill the hatchlings. I’ve been told that at night the flies feast on the little guys blood. A brood supposedly can survive a small amount of that. But when they are established before hatchlings appear they could overwhelm the little guys.
It is not rare to have the experience you describe. I have had it happen three times out of almost 100 nest boxes installed. In 2025 out of 35 nest boxes installed I had 13, or 37% occupied by bluebirds. One nest was abandoned in a similar fashion as you describe. I have no idea what happened but I like to think they found another site that suited them better. I often pair boxes about ten or fifteen yards apart. Bluebirds have never occupied both boxes in a paired setting. I have had a great deal of success with Tree Swallows and bluebirds nesting at the same time in paired boxes. The TS and EBBs do squabble a bit when first establishing their chosen boxes but eventually when nest building and laying start they coexist well. I think they mostly feed differently so they don’t compete completely for food. EBB feed primarily on the ground and TS feed in the sky.
I’m not sure if the three abandoned nests I have had (4 seasons) were abandoned due to predation, unfavorable weather, or maybe they choose a different nest box nearby. Nature is not easy on these birds. A mating pair could have been attacked by predators and if that happened while they were out foraging you would never know. Have accessible water for the birds. If a drought occurs they might have to move out.
Keep trying. Don’t give up. It is very rewarding to experience the little guys fledging.
WI/MI Border, about 100 miles north of Green Bay
Tim C. WI/MI border.
Thank you Tim, good info. I have another box that is about 3 years old on a pole that has had great success, minimum 2 BB clutches a year, I believe I’ve had up to 3 in one season before.
Funny thing is, the first year that box went up, some house wrens nested in it, but after the wrens fledged the BB’s took it over and I’ve never seen wrens attempt to go back to it. I’ve also noticed our wren population is not what it was a few years ago, which is odd because they used to be all over. Maybe the BB’s claimed the territory or something, I’m not sure.
Thanks again and happy birding :)
Good to hear. If I could send you some little stinkers, er Wrens, I would. 🤔 We seem to be having a surge this season.
And today I determined I had another fully built, “abandoned” bluebird nest. I removed the nest and it was very clean with very little dander so possibly truly abandoned.
Curious what is your location? I’m on the WI/MI border so have only experienced two broods per season.
WI/MI Border, about 100 miles north of Green Bay
Tim C. WI/MI border.
Hey Tim,
I’m in western NC (Rutherford County) which is situated about an hour east of Asheville. Appreciate all your input and your experiences seem to indicate what I saw is not completely unusual.
Thanks again!
Lane
- You must be logged in to reply to this topic.