It's a cuckoo summer

By Dave Erler

Black-billed Cuckoo

I say a cuckoo summer, not in the sense that it’s been crazy busy or the weather has been unusual, but in reference to a bird, the Black-billed Cuckoo. When cuckoo is mentioned most non-birders think of a clock, not knowing there really are birds called cuckoos. This summer I have found black-billed cuckoos in three different locations in our immediate area. That is a bit unusual, as this year’s annual breeding bird census was the first time in over a decade that the Black-billed Cuckoo was documented. More often heard than seen, their distinctive monotonous monotone “cu-cu-cu-cu” announces they are present. About as shy and inconspicuous as a bird can be, they often are hidden as they are skulk around in the dense foliage of bushes and trees. If you are lucky enough to see one it’s usually a fleeting glimpse, but this bird is distinctive. The brownish back and white underside are overshadowed by its extremely slender build, long tail with small white spots, and a black slightly curved bill. If you get a close enough, look for its narrow red eye ring. There is another native cuckoo; it is the Yellow-billed Cuckoo, which is similar in overall build, but has larger more conspicuous spotting on the tail, a flash of rufus brown on the wings, yellow eye rings, and as the name suggests a mostly yellow beak. Although the Yellow-billed Cuckoo is often the more common of the two species south and west of New Hampshire, the Black-billed is more often encountered here in the Granite State.

Yellow-billed cuckoo

The reason I get excited about knowing cuckoos are around is their unusual ability to eat hairy caterpillars. Most birds shun eating tent caterpillars and gypsy moth caterpillars as the hairs on these caterpillars are like miniature porcupine quills that irritate the bird’s digestive system. Cuckoos have the ability to eat hairy caterpillars because the hairs are held in the stomach and periodically regurgitated along with the outer lining of the stomach forming what looks like a little bag of hairs. In the years with heavy outbreaks of hairy caterpillars, cuckoo populations help to reduce the damaging effects of these caterpillars on trees.

It’s too bad the cuckoos are so secretive. If they were more common and could be seen as easily as they are heard, no doubt more people would go cuckoo over cuckoos.