Bluebird Bulletin: Part 2

Egg-Laying, Enemies, and Incubation (May 1 – 14, 2025)

The plot thickens in our bluebird saga! In this installment, we delve into the intricate details of bluebird egg laying, culminating in the joyous arrival of a tiny, perfect blue gem. It’s an emotional roller-coaster of a day, as trouble unexpectedly darkens the nest, forcing us to become detectives in a whodunnit involving two very different wren species. Finally, we settle into a period of quiet hope, joining mama bluebird in her dedicated vigil as she patiently warms the precious eggs. Get ready for a series of highs and lows, from heartwarming firsts to nail-biting suspense, as the drama in the bluebird box unfold!

The Anticipated Arrival: Understanding Egg Laying

Bluebird mamas are strategic egg layers, typically delivering their pale blue treasures – anywhere from two to seven – at a steady pace of one per morning. They hold off laying eggs until nighttime temperatures rise, wisely avoiding a frosty fate for their potential offspring. Imagine those tiny eggs, no bigger than a dime or nickel, facing refrigerator-like chills of 40 degrees! Interestingly, even as the first few eggs arrive, mama doesn’t immediately stay indoors at the nest; she and papa prefer the spacious comfort of the outdoors for their nightly rest during the nest-building phase. It’s not until the full clutch is laid – the final piece in their delicate porcelain collection – that mama settles in for the long haul of incubation. Delaying incubation means that all her eggs hatch around the same time. It’s her way of creating a balanced starting line, preventing the older, stronger hatchlings from gaining an unfair size advantage over their later-arriving nest mates. Unattended eggs are vulnerable. Once incubation begins, mama becomes a devoted homebody, rarely leaving her lumpy mattress of a nest for 11 to 19 days, a stretch that must feel like an eternity staring at the same four walls. Thankfully, papa is literally a Grubhub, bringing her food. Mama does take some breaks to stretch her wings, find food, and escape the confines of her cozy, yet undoubtedly monotonous, nursery.

Bluebird Delivery: Our First Egg Arrives

Almost a month had passed since nest building began. May 1 had hit a balmy 80 degrees; nighttime lows were averaging 50 degrees.

On Friday morning, May 2nd Mama was settled on the nest with a newfound stillness, very different from her fluttering nest-building activities. She lay like that for roughly 45 minutes to an hour. (It hadn’t dawned on me that even avian deliveries could take a little while!) When she finally left the nest, we could see the first egg. Oh, the celebration! We were relieved the weather was mild, knowing mama wouldn’t consistently warm that first little egg until the rest of her clutch arrived.

Watch in real-time how this female Bluebird regulates her breathing and delivers this beautiful blue-coloured egg. This process shows how much concentration is needed, and the challenges they face once the eggs arrive. This beautiful three-minute video is by Nestbox Live (October 20, 2023).

Protecting the Nestbox: Baffles for Safety

Someone advised us to add a baffle to the bluebird house pole, fortifying our bluebird house against climbing cats, opossums, raccoons, and squirrels. Ideally, this predator-proof petticoat would’ve gone on during nest construction. Thankfully, the bluebirds’ steady nature allowed Brian to install the baffle that afternoon without a flap.

When Brian assembled the squirrel baffle, Scuttle the cat was on “supervisory” duty. This was quite a feat for a cat who, only several months ago, had been one of the wary, partially feral residents of our woods, only really tame with the neighbor kids. Our consistent feedings eventually won him over, making him receptive to petting. These days, Scuttle strolls inside for breakfast, masters a speedy game of ping-pong ball soccer, and claims my glider rocker without a second thought! But I digress…

Trouble in the Nest: The Wren Attacks

Apart from installing the baffle, we were glued to that first egg all day, like first-time parents peering into a virtual crib. Around 7 pm, Brian checked in – and the egg was gone. Vanished! Our hearts sank. Rewinding less than an hour’s-worth of tape revealed the heartbreaking truth: a house wren, a tiny, feathered assassin. It felt like a tragedy. See firsthand what a wren attacking a bluebird egg looks like in our video. Please be aware that this might be disturbing footage, and you may want to avoid viewing it if you’re sensitive to such content.

A quick online search offered a glimmer of hope: a wren guard, essentially an extended roof or hanging piece that obscures the entrance. This visual deterrent makes the bluebird box less appealing to wrens.

Diagram from NestHollow.com.

Brian swiftly fashioned a very simple wren guard from cardboard that was coated with a clear protective spray. Ideally, this should have been installed right after the first egg appears, BEFORE a wren discovers the opening. Although there was one more attack, there was no further damage. We believe the wren guard to be helpful. Just a reminder: the wren guard is temporary and needs to come down before the nestlings fledge. We wouldn’t want to get in the way of them finding their wings!

Identifying the Culprit: House Wren vs. Carolina Wren

House wrens and Carolina wrens, both small brown birds with upright tails, differ like a street thug versus a more reserved neighbor. House wrens, plainer in brown without the Carolina’s white eyebrow “flash,” have a bold more aggressive personality, making them the notorious bullies of the bird world when it comes to bluebird nests, often attacking eggs and nestlings to seize the property. Carolina wrens, with warmer colors and that distinct stripe, are generally less confrontational. So, when bluebird nurseries are raided, the house wren is usually the feathered gang leader to blame.

Photo from Birdfy.

After the house wren’s initial raid, Brian and I became even more vigilant, our eyes glued to the Green-Backyard app and the YouTube livestream. Just two days later, the miniscule murderer returned, attempting to destroy the next two eggs. Luckily, Brian was watching from inside our house. Springing into action, he raced to the door, bellowing “No, NO, NOOO!” He instinctively unleashed ferocious dog barks. It was a bizarre yet brilliant maneuver, a canine cease-and-desist that sent the tiny intruder packing! Here’s the whole episode caught on camera and microphone…

The barking outburst bought us a ten-day reprieve from the wren. The tiny troublemaker reappeared late one soggy afternoon (May 13), only to be met by mama bluebird, a fierce guardian hunkered down on her nest – NEVER EVER mess with a mama!

Warmth and Waiting: Mama Incubates Her Eggs

Mama laid four more eggs and aside from a couple brief dramas, our bluebird saga has been a picture of tranquility. Mama bluebird is a diligent egg-tender, and you might catch her gently nudging and rolling her eggs within the nest. This careful rotation helps to regulate the temperature and humidity around each developing embryo. Mama bluebird maintains a toasty incubation temperature, around 99-100 degrees Fahrenheit.  It’s almost like she’s a meticulous baker ensuring even cooking! The video uses a time lapse to showcase the bluebird eggs rolling over the course of a single day.

Mama seems mostly content with her snug, yet simple quarters. During mama’s brief foraging breaks our eyes remain glued to the screen.  The incubation period typically lasts 11-19 days.  The four walls can get pretty boring for two or three weeks! Take a peek at the video to see what goes on while she incubates her eggs. Her future hatchlings are worth the temporary confinement.

Spoiler Alert! The eggs hatched in two weeks, on May 19. But that’s another Bluebird Bulletin! To stay updated on this exciting development and peek into their cozy nursery, be sure to check out our bluebird nest cam on our YouTube channel, https://www.youtube.com/@azarelgreetings3555 !

This photograph captures a moment that truly takes my breath away! Mama and Papa Bluebird “posed” with the keyboard from my childhood piano on the same day their precious eggs hatched. The photograph looks beautiful as a square canvas giclee or as a 12”x18” giclée with a quote. Coming soon at AzarElGreetings.com.

I’ve been fortunate enough to capture some beautiful and unique bluebird shots. The freshest photography appears first on Facebook or Instagram. Experience bird photography reimagined at AzarElGreetings.com