Pls Explain Odd (?) Bluebird Behavior (4 Viewers)

[Claude-ccc]

I'm entering my 3rd Bluebird nesting season here in Baton Rouge (LA), and I observed a Bluebird nesting behavior I'd like explained. The female initiated nest building 2/15/25 and completed it 2/22/25. Clutches later in the season are typically laid immediately following completion of the nest because weather is warm. No egg laying has occurred as of 2/27/25, presumably because local weather continues to be chilly (morning lows into the 30s-40s). But the question is why the nest was built so early, perhaps weeks ahead of when it will be used? Last Spring I had Chickadees occupy the nesting box first. The nesting box was quickly freed up for Bluebirds when I removed a female Chickadee due to her unfortunate death from an unknown cause after laying only one egg, and no sight of the male Chickadee. So, is this Spring's early Bluebird move-in a kind of Bluebird advanced reservation on the nesting box? Is this the way preparation for the first clutch of the season proceeds? Thanks in advance for any insights.

 

[gem6155]

You might have house sparrows that also like to steal the bluebird boxes & will easily harass & kill even much larger bluebirds... and most certainly a tiny chickadee. Have you seen any around/ are they also found in your area? Check your state regulations, but bc house sparrows (& house finches) are an aggressive invasive species that poses a threat the your natural environment song/birds - they may DEP may even encourage ppl to cull these birds (humanely) and often to destroy their nests & eggs. Again, check with your local DEP - but I'm going to bet they have something to do with all of it. Keep us posted! Am very curious - I actually just saw a house sparrow going after my bluebirds over a new bluebird house I just put up tonight. Online now looking for way to scare them off, while keeping my bluebirds still coming...

 

[Claude-ccc]

.....Thanks for your thoughts.
.....Laying of 5 eggs was completed March 5 (one per day), so in the end Nature did what we expect Nature to do. Nature operates on its own timetable, which might at times look perplexing to humans, although in this case there was good reason to let the last really cold days of winter pass.
.....House Sparrows are dissuaded by blocking the box hole or putting a large pine cone inside the box. The House Sparrows give up after a few days. Luckily, that has not interfered with the Bluebirds.
.....I have conditioned the Bluebirds to regard the nesting box as a food source by placing peanuts inside (with the exception of active nesting periods.) Regardless of season, male and female enter the box and come out with a peanut. Perhaps this is why the Bluebirds come back even when the box hole is blocked for a few days.