I was so relieved when the Bluebird pair survived our 3ft snowstorm. And I was delighted when they started building a nest in one of the boxes.
Then the Tree Swallows arrived, and they tried to claim that nest box, but the Bluebirds persisted, and claimed it as theirs. For over a week I saw only the Bluebirds around that box.
Then I checked it and found this:
Dammit, when did the Tree Swallows sneak into the nest!
I was beyond disappointed. Tree Swallows are cool, but I want Bluebirds!
But then Wednesday, when I stepped out of the back door to open up my little greenhouse for the day, a Bluebird flew out of the box! I checked, and sure enough, still 5 little pink eggs! Is the Bluebird sitting on the Tree Swallow eggs?! WTF!?!
Beyond baffled I emailed the story and pictures to a couple folks who know way more about Tree Swallows and Bluebirds than I do. The response: Its still WAY too early for Tree Swallows to be laying eggs at my latitude, and despite the color those eggs are shaped like Bluebird eggs! I was vaguely aware that sometimes Bluebirds will lay eggs so pale as to look white, but not that they can be so pale as to look pink! But it is a known phenomenon!
I’ll be looking to add powdered calcium to the live mealworms I feed, and I’ve contacted the local Bluebird society to see if there’s anyone who’s interested in banding the female for study.
The things you learn!