Natural History, July–August 2017
I’m usually motivated by direct experience, but this time motivation came from viewing a photograph of two nightjars perched on the ground. They looked like the whip-poor-will of North America, but these were diabolical nightjars of Indonesia. I was intrigued because the two were so close to each other that they were touching, an enigmatic behavior because nightjars, birds of the night, are solitary, and this species was known as one of the rarest bird species on earth.
The photograph was in a book review written by N. J. Collar and published in Kukila, the journal of Indonesian ornithology. I had read it in 2010, where I first saw the image captured on camera by someone named Yong Ding Li in June 2007. Li happened to be at the right spot at the right time with a camera, in Lore Lindu National Park in Sulawesi. His photo was of the diabolical nightjars, one of several bird species discussed in the reviewed book (The Snoring Bird, which happened to be mine, and about my father, Gerd Heinrich, who had discovered the diabolical nightjar—also officially known as Heinrich’s nightjar—in 1931; it was not seen again until 1996).
Nightjars typically lay two eggs, so the two birds in the photograph could potentially have been the young of a nest. But from their plumage they seemed adult, and if adult, then they were likely mates—but even so, why would they be pressed next to each other? Since they were in the hot lowland tropics, they could not have been huddling for warmth, so why were they doing it? With nothing more to go on except the knowledge that this was an extremely rare bird, I filed the image away as a faint memory of an interesting anecdote, and left it at that. But a year later the potential enigma came back to me, this time on a Christmas card sent to me by someone in Alberta, Canada, someone whom I had also never met.
The card was decorated with a photograph of the same extremely rare species, the same diabolical nightjar of Sulawesi, except that the signer of the card, M. P. Marklevitz, referred to it by the third of its three names, the satanic nightjar. This photograph was taken in the same nature reserve as the other, and like the other photograph, it also showed two of the birds perched next to each other on the ground. This photograph, though, had been taken more from the top than with a head-on view, so the birds’ elongate tails were clearly visible—they were definitely adults! Thus, these were likely a mated pair, and Mr. M. Patrick Marklevitz wrote me, “I managed to locate and photograph two pairs in the upper reaches of Lore Lindu Park.” Again paired? What amazing coincidences, I thought, and the wonder increased, although I still saw no opportunity nor had the wish to travel to Sulawesi to track down such a rare bird in the jungle. But the images of it did not go away.
Marklevitz’s photo showed what I inferred might have been a third bird, possibly young, partially covered by the pair. It was either this (such ground-nesting birds have young that closely match their background of leaves and other debris) or I had been fooled by a fortuitous arrangement of dry leaves that created a Rorschach illusion in my mind. To find out which, I tracked Marklevitz down several years later (through his internet presence as a nature photographer), to try to find out more about his nightjar photograph. He led me to exactly what I had needed to see: a website, “Oriental Bird Images,” that turned out to be a treasure-trove of information collected over decades by dedicated bird watchers. And so, now seven years later, I was suddenly provided much more information than I could ever have dreamed possible.
On this website, I viewed hundreds of photographs posted of Indonesian nightjars, birds of the genus Caprimulgus (fifteen species) and Eurostopodus or eared nightjars (three species). I viewed a total of 294 photos of roosting birds (excluding photos of flying birds, multiple photos of the same birds, and portraits). Twenty of these photos were of the diabolical nightjar, and seven were photos of pairs, whereas within the 274 remaining of other nightjars, there had been only one with two birds in the same frame. That is, unless in the unlikely event that birders deliberately desisted from photographing single birds of the diabolical, then pair roosting is an overwhelmingly favored behavior by this specific species.
The photographs were from all over Indonesia, and all of the twenty photographs of the diabolical were taken in the Lore Lindu Park in north-central Sulawesi.* I also Googled “pair-roosting nightjars” and found five videos and five photographs of the Trinidad white-tailed nightjar (Caprimulgus cayennensis), photographs of the blackish nightjar (C. nigrescens) and the collared nightjar (C. enarratus) from Madagascar, but none in pairs.
Why would the satanic nightjar stay paired up and close together? Staying together would promote monogamy, but in many birds, that is achieved or maintained secondarily by site-fidelity. Staying wedded next to each other seemed like potentially extreme monogamy. Is it selected because under some conditions it provides insurance for having a suitable mate handy?
Such monogamy might become crucial where the population is especially sparse or the breeding season extremely short. It might also be necessary where the annual ritual of courting is costly. When a species becomes rare and the ability for individuals to find a mate becomes a factor limiting reproduction, the species might distribute itself increasingly more locally into specific localities. The current conservation status of this diabolical nightjar is “vulnerable,” and it is indeed listed as a “restricted range species.” These descriptive labels would have applied to this species already nearly a century ago, and may to its current rarity.
My father, with his wife, Anneliese, and her sister Liselotte as bird preparators, discovered this nightjar in 1931, only after they had explored and collected all over Sulawesi (then Celebes) for two years. They secured their single specimen at the very end of their bird-collecting expedition, financed by the American Museum of Natural History in New York. The enterprise had been instigated by Leonard Sanford of that museum, and Erwin Stresemann, then the world’s premier ornithologist, at the Museum of Natural History in Berlin. The museums had tasked the expedition with the special mission of bringing back a rail, Aramidopsis plateni, that was thought to be extinct, but was rediscovered in 1932 after a two-year search. It was known only from the remains of one specimen.
The crew had been trying to resurrect this rail to please their sponsors. By the time their two years were up, the long-lost and long-sought rail that they would later refer to as der Vogel Schnarch (the snoring bird), after later hearing its call, had by then still not turned up—but a shipment of their bird catch had reached Berlin. Stresemann, on examining it, reported back that it contained “fantastic discoveries.” One of the major ones was this nightjar.
The discoveries from the Minahassa area induced Stresemann to contact the American Natural History Museum’s noted philanthropist Richard Archbold about donating another $10,000 to keep the expedition going.*
Stresemann had described the nightjar, and therefore had the honor and task of naming it. For a species name he chose diabolicus. Hence the common name of diabolical nightjar. His rationale for inventing the name may never be known, but I suspect he may have implied, tongue-in-cheek, that devilish forces had been at work to produce this totally unexpected rare and precious new bird, only because of his and Sanford’s efforts to get the crew to stay on beyond the scheduled time to find the rail with the snoring call.
As reported by K. David Bishop and Jared M. Diamond in 1997, who then called it Heinrich’s nightjar, the bird was not rediscovered until May 1996, and in the previously mentioned Lore Lindu National Park. This apparently highly local distribution (or a hot spot for birders seeking to add it to their life list?) is some eight hundred kilometers from the site of its original discovery sixty-three years earlier, where it has so far not been recorded again. Its rarity and restricted range are apparently real, and sustained isolation for long periods of time would predictably give a reproductive advantage to individuals who, if they are so fortunate to find a mate, stay together.