What Bluebirds Have For Breakfast

If they'd only clean up behind themselves!

Baby Bluebird sister in the back wants that speck right between brother’s back toes.

The window (I can lean over and touch just beyond my computer monitor) is a very small portal to the outside world. The shade is pulled three-quarters down, since the glass faces west. The light floods in, blinding my view of the screen and creating distracting reflections on the glass. It is more of a peephole than a portal to nature.

Even so, I have a good view of a few feet of the rail around the deck, and it has been a busy place for the bluebirds this year. They don’t clean up after themselves.

The entire porch rail will need a good mopping-up of bird leavings--but lately, more mess comes from the bug juices from their messy meals than their post-meal droppings. They are not dainty eaters, even as their diet changes from soft and wet to crunchy and harder to swallow.

MENU CHANGES

Up until a week ago, bluebirds feasted and fattened on the abundant grubs in the yard-- beetle pupae whose invisible presence is apparent underfoot by the dead grass (grubs eat the roots) and the vast network of mole tunnels. Without those grubs, we would not have the mole issues. The yard is a treacherous spongy mattress of grass over miles of empty tunnels that you sink into with each step.

A month ago, after the ground thawed, the hundreds of fat juicy June Beetle grubs were close to the surface of the soft earth. Parent bluebirds brought them to the rail--the threshing floor. There, he or she would pound them into a pupal pudding until they stopped squirming futilely about just before they became food--either for the adult bird on the rail or babies in the nest boxes.

But since maybe 10 days ago, lunch and dinner has been the less wet and slimy, mostly mature beetles (or more accurately, almost mature and not yet emerged out of the ground.) The chitinous armor of food in this form takes more work to prepare--either to eat and run or parcel out to the kiddos.

I watched a momma bird do just this (but did not grab my phone in time for a video), and poke parts into the open beaks of two youngsters--a male and female, almost as big as momma--who appeared again yesterday, in the rain, waiting to be fed. I had my phone ready, but momma never came this time, as the two pushed and shoved like brothers and sisters do.

You can watch the 30 second video by clicking the link below. (Momma signaled them from off-camera rather than bringing the meal to the rail this time, and they disappeared.)

Bluebird juveniles waiting for lunch: 30 second video

SO HERE'S THE THING

As I watched these two birds-of-the-year (first brood of two before end of summer) I thought about the world these birds live in, made possible by the diet of highly-nutritious life underground.

My observation is that bluebird meals on my porch rail consist of June beetle grubs (some fat as my thumb) from the thaw until mid May, followed by almost-mature tan or brown or shiny-green beetle pre-emergent or recently post-emergent adults they find hiding in the grass during the daylight hours.

It is about time for adult beetles to rise up in numbers. As in summers past, a host of them will emerge as we watch from the porch rockers, on a warm June evening.

And it occurred to me that these birds are able to completely digest their beetle diet, be it a squishy grub or hard-shelled beetle packaged in a chitinous shell. Bird droppings (cloacal contents mixing both digestive and renal waste) are usually just liquid white without lumps. You know the thrill of having such a slurry hit your car windshield, just after washing it. Right?

No leftover bug bones, the food processed completely. How does that work?

What would it be like if I ate a fat beetle grub? Or a crunchy adult? Could I love to love bug-burgers? Could I even digest enough to keep me alive?

Well, I could harvest a meal’s worth of emerging adults and check it out.

To gather a meals-worth of emerging June beetles, I could lay out a net over a mole-infested and grub-heavy part of the yard (I have bridal veil I use in the garden for this)--say a 10 x 10 foot square. In this way I could capture however many June beetles emerge, and get an idea of insect density as a measure of food production for blue birds in my yard.

QUESTION: if push came to shove, could we incorporate insects as part of a survival diet before the garden comes in, should the need arise? If we got used to the idea of insects as food, how would that impact our diets and our planet?

Beetle grubs: they're not just for bluebirds anymore! To be continued in the next installment.

June Bugs: What They Look Like, How to Get Rid of Them, and More