7-3-2020 chickadee with fecal sac.jpg

Baby food for black-capped chickadees includes spiders to support brain development, and several thousand caterpillars over the course of a summer.  

My tires crunched on gravel as I turned into the parking area along the Namekagon River. Right on cue, a black-capped chickadee darted across the clearing and dove into a boundary post with a ragged top. Seconds later, it emerged and vanished. 

A friend had tipped me off to the location of this nest, and I’d finally stolen a moment to check it out. Chickadees are my favorite birds! I parked away from the nest, at a distance that I thought would work for taking photos without interfering. But I couldn’t resist a sneak peek first. As long as the young aren’t so old that they’ll fledge prematurely, a quick look at a nest does not usually cause harm, but I didn’t take this invasion of their personal space lightly. 

Peering down the tube of rotten wood, topped with mosses and red-tipped lichens, I found five orange mouths with yellow rims aiming up at me. No parent could miss seeing those targets, even in a dark cavity. A smattering of scraggly feathers was visible, as well as a rim of grassy-looking nest material. Having gathered that data, I quickly backed away.

A loud chickadee-dee call stopped me in my tracks, and I scanned the nearby shrubs. Chick-a-dee-DEE it called again, and this time I spotted the adult bird perched among the leaves. Its mouth was full. I quickly snapped a few photos before retreating to my car — the official wildlife blind for birders. 

As I settled in, my phone chimed. It was a text from my sister-in-law, inviting me to a party to celebrate my oldest nephew’s high school graduation. My how time flies.

Turning back to my camera, I zoomed in on the photos I’d just taken. One green caterpillar, one brown larva and a leggy spider were crammed into the chickadee’s little beak. The caterpillar dangled like a piece of wayward spaghetti. This is typical baby food for chickadees. In fact, Doug Tallamy, author of “Bringing Nature Home: How You Can Sustain Wildlife with Native Plants,” has calculated that a single family of chickadees will eat between 6,000 and 9,000 caterpillars in a single summer. That’s a lot of free pest control. While the seeds in your feeder are fine for adult chickadees, the growing chicks need higher quality food. Caterpillars contain more protein than beef. 

During the first five days of a chickadee’s life, spiders are an especially important baby food, because they contain high levels of the amino acid known as taurine. Essential for brain development, taurine promotes visual acuity, overall intelligence and resistance to anxiety in mammals. Initial experiments with chickadees’ cousins demonstrated a connection to bold behavior and good problem solving skills — which are integral parts of chickadee personality. 

It only took a few minutes of my social distancing before the parent with the beak full swooped in to the nest. Slow to click the shutter, all I caught was a blurred tail as the bird dove stealthily into the post. 

For the next three days I popped in on my way home from work to watch the parents in action — never leaving my car. I brought a tripod, and even took some videos. I began to notice patterns in their behavior. First there would be movement in the closest tree, and then a call. If I heard their chick-a-dee-dee alarm call, it might be several minutes before the parent would deliver their mouthful to the nest. But their “hey sweetie” song, also used for attracting mates, seemed to be the all-clear. 

Within seconds of singing that song, the parent would swoop in to the nest. Usually they dove like the underdog in an action movie, with a recklessness that made me cringe. A few times, though, the busy parent perched on the edge of the post to look around, and possibly to show off the impressive bouquet of colorful bugs clamped tightly in their beak. 

Their exit from the nest was a little less rushed, and often the parent would perch for a few seconds as if catching their breath. Often on the way out they’d have a little brown and white blob in their beak. This membrane-wrapped fecal sac is a natural end to all the bugs that went in, conveniently packaged by the chick’s own digestive tract for easy removal.

If that sounds like a brilliant idea to you, well, it is. Chickadees rate high on the scale of bird IQ. You know that large, adorable head that makes them so cute? It holds a brain twice the size of other birds in the same weight range. 

After leaving town for the weekend, I was eager to return and check on “my” chicks. Pulling in, I immediately noticed new splinters peeling away from the post. Did something get them? I rushed over to peek in. The tops of five, sleek, black-and-white heads were outlined in the dark. I left as quickly and quietly as I’d come, and never figured out who attacked the post. Once chicks are almost ready to fledge, they may leave the nest prematurely when disturbed, and face an even more dismal survival rate than normal. Luckily, they stuck tight. But, four days later, they were gone. Hopefully they fledged and are now hidden in the bushes, still begging for food. 

Anyone who’s watched a nest full of baby birds knows how thrilling it is to see them develop quickly from squawking, scraggly things into fluffy fledglings and then sleek young adults. 

Humans aren’t so different. The 18 years I’ve spent watching my nephew become an adult now seem just as short as my 10 days of chickadees. Both birds and boys have big heads with big brains, and lots of curiosity. Despite those similarities, the differences are many. For one, my sister-in-law hates spiders and will be glad to learn that she escaped using them as baby food. On the other hand, chickadees might really be on to something with the way those spiders come out the other end. 

 

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