This past weekend marked the 26th annual Great Smokies Birding Expedition, a gathering of onrnithologically-inclined friends. On Saturdays, to get things started, we always walk around Bryson City, tallying the common species that prefer a semi-urban setting. The highlight of the morning was the observation of cliff swallows nesting for the second straight year on the sides of the I-beams that support Everett Street Bridge. Their mud-cup colonial-style nests are a work of art.
After lunch, we moved to the Blue Ridge Parkway and birded the different forest zones into the spruce-fir forest at the intersection of Balsam Mountain Road and the BRP. The initial highlight of that stop was hearing a Canada warbler singing, even though he remained hidden from view in the rhododendrons. But the Canada warbler’s place of honor was replaced when someone said, “Black-billed cuckoo.” Sure enough, from the nearby woodlands came the ku-ku-ku-ku-ku notes of the black-billed cuckoo. They sound to me like someone tapping a coffee cup rhythmically with a spoon.
There are certain sounds that haunt the southern highlands: wind sighing in boughs of spruce-fir; the ongoing, ever-changing murmurs of a mountain stream; the “singing” of a timber rattler’s segmented tail; and the forlorn calls of the cuckoos.
No bird species are more secretive. 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. It is mostly a “voice” that arises somewhere in the near distance then fades away.
Many rural residents know the more common species as the “rain crow” since its guttural “ka-ka-kow-kow-kowlp-kowlp-kowlp” calls are often sounded just prior to a late evening thunderstorm. (The distinctive “kowlp-kowlp-kowlp” portion of the call sounds something like a small dog barking.) The cuckoos on our property often sound a single “kowlp” note rather than the full vocalization.
The second cuckoo species that nests here in the mountains, mostly in the upper elevations, is called the black-billed cuckoo because it lacks the yellow lower mandible of its cousin. I’ve never seen even one black-billed cuckoo, but I have heard its rythmic “cu-cu-cu cu-cu-cu cu-cu-cu” calls on more than a few occasions, most notably in the region of Blue Valley near Highlands, the Rainbow Springs section of the Nantahala River, and on the Balsam Mountain spur road of the BRP just beyond Mile High Overlook.
Both species winter in South America. They arrive in our region during the last week in April and usually depart by late October. If you see a yellow-billed cuckoo in flight, the most distinctive feature will be a double row of large white spots beneath the tail. The reddish flash of wing against the brownish body is also diagnostic. Henry David Thoreau described the bird this way:
“The cuckoo is a very neat, slender, and graceful bird. It belongs to the nobility of birds. It is elegant.”
The entry for the black-billed cuckoo in the Birds of North America Online (subscription) site contains these observations:
Graceful in flight but skulky and retiring in habit, the Black-billed Cuckoo is among North America’s most elusive birds. It is frequently confused with the more common Yellow-billed Cuckoo ... with which it shares similarities in plumage, behavior, and many vocalizations. Although both species occur ... through much of their ranges, the Black-billed Cuckoo has the more northerly distribution. In addition, Black-billeds prefer more densely wooded areas and can be found more frequently within coniferous vegetation. The Black-billed Cuckoo is rarely seen during migration and on wintering grounds in South America due to its silent and secretive manner. As a result, its nonbreeding distribution remains controversial. In North America, it is among the later migrants to return each spring; arrival on breeding grounds is announced by its staccato, repetitive call— cu-cu-cu cu-cu-cu —uttered as individuals fly overhead on late spring evenings. Vocal night flights increase as breeding commences. These flights, in concert with its quiet, sluggish behavior during the day, has led some ornithologists to suggest that the Black-billed Cuckoo is nocturnal in summer.
On Saturday, we heard the black-billed cuckoo calling for a while. Then the sound faded into silence. No one glimpsed the bird or even knew for sure where it had been. But the next time you’re in the high country and hear those steady rhythmic notes you’ll know what it is. With luck on your side, you might even see the bird. But don’t count on it.