Humane Gardener

If you want to see the yellow-billed cuckoo and other elusive animals, leave tent caterpillars alone. Let forests grow back. Respect all your wild neighbors, and watch life thrive.

The clouds finally came without bluster, a darkening of the western sky that was more deliberate than all the late-afternoon blowhards who’d passed over in recent days while ranting on about nothing. Evening after evening for weeks, the baseless thunder and rambling winds had left us high and dry. As the parched land contracted, my world did too, and I focused only on keeping my growing habitat alive.

But last Wednesday’s teaser was different, at least to me, though apparently not to the tree frogs. Usually the first ones to chime in at the slightest sign of rain, they remained silent. Maybe they, too, were tired of Mother Nature’s false alarms and needless distractions.

Estimating that I had about five minutes before the downpour, I headed out the back door and down the path to ask the green frogs why their diminutive friends were being so skeptical. Just as I reached the pond, a bird of uncertain size and shape flew past me and into a walnut tree. Zooming in with my camera, I saw that his beak and coloring differed from that of anyone I’d seen here before. My poor eyesight poses a challenge, but many of my discoveries come from observing basic divergence from general patterns, and I went inside to report the good news to Will: “I think I saw a new bird by the pond!”

As the skies opened up outside my office window, a quick search of our bird books provided a photo match and a name: My new friend was a yellow-billed cuckoo. Further reading online revealed more interesting aliases: “Common folk names for this bird in the southern United States are rain crow and storm crow,” read an iNaturalist description. “These likely refer to the bird’s habit of calling on hot days, often presaging rain or thunderstorms.”

My first reaction was to cry. I cried with gratefulness for the rain. I cried with joy that I had met a magical “rain crow” heralding the storm’s arrival. I cried with awe as I thought about how much the animals teach me when they fly or crawl or leap into view and upend everything I thought I knew about the world.

Once I’d gotten my bearings, I started wondering how I’d been able to see a yellow-billed cuckoo — a bird universally described as elusive and hard to observe — in my own backyard. Looking through my pond images from the previous week and discovering the cuckoo in more than one of them only deepened the mystery. “No bird is more secretive,” writes naturalist and author George Ellison in The Smoky Mountain News. “Seldom leaving the shrouding foliage, the cuckoo sits motionless. When it does move, the cuckoo creeps about with furtive restraint. Seeing one is possible but unlikely. For the most part, this is a bird that you hear.”

Image of Pond in morning light — Yellow-billed cuckoos like densely vegetated deciduous woodlands near water. Once all lawn, this area has grown up into a mini woodland.

Had I heard yellow-billed cuckoos before but just not known it? I wasn’t sure. But in learning about their habitat needs, I realized why I might be seeing them now. We have everything they need. They like to blend into dense vegetation of deciduous woodlands. They eat primarily caterpillars, devouring as many as 100 tent caterpillars in a single sitting, and they’re happy to add cicadas, katydids, crickets, beetles, ants and spiders to the menu. Elderberries, blackberries and wild grapes—all abundant here—provide some sustenance into the fall as well.

Many birds avoid hairy caterpillars, but the Cornell Lab of Ornithology explains the special mechanism that yellow-billed cuckoos use for safely processing the spines of gypsy moth caterpillars, fall webworms, tussock moth caterpillars, and others: “Those spines end up sticking to the lining of their stomach. To get rid of the spines, they periodically shed the stomach lining, coughing it up in one giant pellet, similar to an owl.”

Image of tent caterpillars — Our habitat fits the bill of the yellow-billed cuckoo — literally! The birds’ curved yellow beaks help them navigate webby nests of tent caterpillars to snatch their prey.

Having recently watched cuckoo wasps trying to lay their eggs in the nests of organ pipe mud dauber wasps, I was well aware that the term “cuckoo” implied brood parasitism and wondered if the yellow-billeds were partaking in such sneaky activities in our habitat. But Mary Sonis, another North Carolina naturalist, had a gentler explanation of how they earned their name. They do make their own nests, but sometimes they run out of time—like a human mother who goes into labor on the way to the hospital. “When there is a significant caterpillar irruption, the food supply for the Cuckoo has a precipitous upturn, and the female is ready to lay her eggs in very short order,” she writes in the Raleigh News & Observer. “The nest is simply not ready for the early arrivals. Sometimes, the nursery isn’t finished when nature calls.”

But unlike cowbirds, who lay their eggs in other birds’ nests and then skedaddle, cuckoos stick around, Sonis writes, often helping to feed both their own young and the chicks of the host bird’s nest: “What perfect guests!” When incubating their own nests, cuckoo parents share sitting duties equally during the day, and dads take over for the night.

It hasn’t been difficult to create habitat for these hard-working birds. Where once there was turfgrass, we’ve let a mini-forest grow; it’s now filled with sassafras, walnuts, tulip poplars, staghorn sumacs, hackberries, clearweed, ferns, asters, goldenrods, violets, rushes, sedges, nimblewill, boneset, Indian tobacco, black-eyed Susans, white vervain, and many other natives—some of which we planted and most of which we didn’t. I was delighted to learn that yellow-billed cuckoos also like water; as small as our new pond is — at 8 feet in diameter — it seems to suit the cuckoo just fine.

Image of mini woodland 2 — This area adjacent to the pond sprouts new plant species each year, providing an endless source of discovery for me and an increasingly diverse menu for animals of all kinds.

Perhaps most helpful of all to our bird friends, we let the insects be, and that includes the tent caterpillars and the fall webworms. If we have gypsy moth caterpillars, I don’t even know it, but I would leave those too—not just for their own sake but for the cuckoos and anyone else who needs a little refuge from the food-desert lawnscapes that surround us. No one is a “pest” here; if anything, the only pests in the neighborhood are those on two legs constantly wielding gas-powered chainsaws and riding around on giant mowers like they’re at the Indy 500.

Because we welcome everyone, including the animals many gardeners squish or drown or spray or trap, life is ever evolving and diversifying. Species listed as rare, uncommon, or threatened elsewhere — from American bumblebees to meadow fritillaries — have found refuge for the very reason that we don’t arbitrarily decide which plants and animals get to stay and go based on random aesthetic values or cultural notions of who is “good” and who is “bad.” Though my encounter with the prescient rain crow felt like a magical experience, his presence was likely no coincidence —and was rooted in our desire to help everyone in our habitat put down roots, enjoy the view, and stay a while.