Burras: These chicks have flown the coop

Todd Burras, Eyes on the Outdoors
Special to the Ames Tribune

Heading out of the house toward the truck that was parked in the street, what stood out was what an unusually calm morning it was, one filled with sunshine and bird song, much, much bird song.

In the great treetop chorus comprised primarily of migrating warblers, catbirds, tanagers and grosbeaks, it was a local bird, a regular visitor to our backyard throughout the past year, that shook the serene atmosphere and, in doing so, stole my attention from the other birds. From the top of a river birch on the south side of our house, a black-capped chickadee began incessantly calling. This wasn’t one of their familiar “hey, sweetie” or “chickadee-dee-dee” calls, but rather a series of “dee-dee-dee-dee-dees,” indicating an urgency rarely heard in our yard.

My first impulse was to look overhead, past the limbs of our large flowering crab tree and toward the upper reaches of one of our neighbor’s massive silver maple, a giant limb of which towers over a portion of our yard. It was there that I had recently noticed a pair of Cooper’s hawks building a nest. Was it the chickadee’s realization of the predator bird that set off its alarm calls to its mate, somewhere on the other side of the house? Or was the seeming distress call not a warning at all, but rather some sort of communication to its mate or brood for some completely unrelated reason? I’d have to wait until much later in the day to see if I could make sense of what the ruckus had been about.

This scene, as part of a larger story, had begun a few weeks prior when I’d asked our neighbor who has a much more open backyard than ours and which also runs into another large open green space, if I could install a pole with a bluebird nesting box on it. He graciously agreed, and I set it up.

The nesting box was a longshot taken at trying to attract a bluebird into the vicinity of our home and yard. Historically, bluebirds were secondary cavity nesters that used holes in trees or fence posts excavated by woodpeckers and other birds in woods near open pastures and fields. But in the past century or more, they’ve become accustomed to using manmade nesting boxes. Attracting them to small urban backyards like ours is uncommon, though not unheard of. It was with a glimmer of hope that we might attract an unconventional bluebird couple that would take advantage of our housing offering.

Instead of bluebirds, however, a pair of chickadees seized upon the opportunity to be the first inspectors of a new housing unit in the neighborhood, and they quickly began moving in. The pair collected moss to make a base to the nest that would eventually include grass, rabbit fur and, of all things, tufts of my hair that had been discarded in the grass after Stephanie gave me a trim in the backyard.

It wasn’t long after the completion of the neat, compact nest that the first of what would eventually become six eggs showed up. Soon after, the female moved in and started incubating the eggs (a process that lasts from 12 to 13 days), and the male got busy bringing her food. Once the eggs hatched two weeks later, however, the real work began for both parents as they assumed the never-ending task of feeding their ravenously hungry offspring.

According to Doug Tallamy, an East Coast entomologist who has championed a national crusade touting the necessity of using only regionally native plants in creating a healthy garden and yard ecology, both chickadee parents are busy from morning to night bringing their little ones an average of one protein-rich caterpillar every three minutes. Based on Tallamy’s observations and calculations, chickadee parents need to find 350 to 570 caterpillars every day, depending on the number of their offspring. When accounting for the 16 to 18 days it takes to fledge the young that’s a total of some 6,000 to 9,000 caterpillars needed to bring a brood of chickadees to maturity.

Talk about exhausting work. No wonder the parents try to get the youngsters out of the nest as soon as possible so they can learn to start foraging for themselves.

That’s also what brings us back to the morning I stepped out of the house and started toward the truck. Rather than alerting its mate to the potential dangers posed by a Cooper’s hawk (I scoured the surrounding trees and didn’t see any sign of one), the boisterous chickadee was more likely trying to lure its young from their comfy nest. It’s a common tactic undertaken by parents once they determine its time for the young to fledge. The adults often will withhold feeding the young birds for a time that morning all the while calling in an effort to get the youngsters to leave the box.

In this instance, one of the young had heeded the calls to which I’d been privy to that morning. That afternoon upon returning home from work I immediately checked and counted just five babies packed tightly together in the relative safety of the nesting box. Meanwhile, flitting around in the nearby bushes, the two parents chattered back and forth with the one brave fledgling that had essentially flown the coop.

By the following afternoon when I checked, the five other babies had followed suit, leaving the nesting box empty and quiet but the surrounding trees and shrubs full of the cheery songs and calls of a happy family of black-capped chickadees. “Chickadee-dee-dee.”

Todd Burras can be reached at outdoorstoddburras@gmail.com.