Rediscovery of the Karimui Owlet-nightjar

The Allied Owlet-nightjar (Aegotheles affinis), endemic to New Guinea, is currently considered to comprise two subspecies: the nominate, restricted to the Arfak Mountains of the Vogelkop Peninsula, in West Papua, and A. affinis terborghi (del Hoyo et al. 2016, Beehler & Pratt 2016). The latter is known only from a single specimen taken on 16th August 1964 at 1100 m in the Karimui Basin, in the Eastern Highlands of Papua New Guinea (Diamond 1967). This individual was presented to Jared Diamond by a native who said he had caught it by hand while it was sleeping on a branch in daytime. Diamond named this distinctive race after Dr John Terborgh, who had accompanied him on a collecting trip to Karimui in 1964.

After its discovery, A. affinis terborghi was included as a form of the Barred Owlet-nightjar Aegotheles bennettii on account of its close similarity to the two mainland races of A. bennettii: the nominate and A. b. wiedenfeldi (Sibley & Monroe 1990). However, it is much darker above and also much larger than either of these these races: its wing length of 154 mm greatly exceeds the 121–128 mm of A. b. bennettii. Mitochondrial DNA differences also suggest a relationship to A. a. affinis, as well as the splitting-off of both A. affinis races from the A. bennettii clade (Dumbacher et al. 2003). The two known populations of the Allied Owlett-nightjar inhabit low-altitude montane areas some 1400 km apart. They may be two distinct species (Beehler & Pratt 2016) but further observations and voice recordings are required to clarify the situation.

I have a keen interest in nocturnal birding and a passion for Papuan birding so the old volcano at Karimui has been a tantalising prospect for me for the past few years. I was keen to see what avian secrets might be waiting there. I enquired about visiting the region for a couple of years and was finally able to travel to Karimui in July 2016, together with Markus Lagerqvist, Roger McNeill and local guide Daniel Wakra. Despite travel difficulties we had four nights in Karimui to find an owlet-nightjar, although this suddenly seemed a tall order since we had no recordings or information on where to look. Our first night was in the Pastor’s house in Karimui village and early next morning we set off with an ever increasing entourage, aiming to climb as high as we could and then camp. We finally came across a small wooden house on the edge of a clearing and, as rain seemed highly probable, we decided to use this as our base from which to explore the higher areas.

Five local lads came along with us for our first real exploration and as we approached 1570 metres one of them shook a rattan vine. Remarkably, a grey-looking owlet-nightjar flew out and landed directly above Markus and myself. Our first view was looking right up from underneath. My camera was ready so I instinctively took a couple of shots before very quickly repositioning myself to face the bird. I managed a couple of frontal photos before it flew off. To my relief and surprise it was the hoped-for Karimui Owlet-nightjar, the first ever live observation 52 years after its initial discovery – and I’d managed to photograph it too! The bird was quickly relocated and we were able to watch it for an hour or so in rather poor light but it did move several times and at one point briefly disappeared into a small hole. It finally settled, giving unobstructed views, until enough photos and videos were taken. The owlet-nightjar finally out-stared me and rather reluctantly I made my way back down to camp not really believing what had just happened. What had seemed likely to be a rather hopeless search had resulted in a truly wonderful and prolonged sighting of this extremely rare bird. Some sound recordings were made the following evening but the bird only made one series of calls at dusk and there was a lot of background insect and frog noise.

References

Beehler, B.M. & Pratt, T.K. (2016). Birds of New Guinea: Distribution, Taxonomy, and Systematics. Princeton University Press, Princeton, New Jersey.

Del Hoyo, J., Collar, N. & Kirwan, G.M. (2016). Allied Owlet-nightjar (Aegotheles affinis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.

Diamond, J.M. (1967). New subspecies and records of birds from the Karimui Basin, New Guinea. American Museum Novitates 2284: 1–17.

Dumbacher, J.P., Pratt, T.K. & Fleischer, R.C. (2003). Phylogeny of the owlet-nightjars (Aves: Aegothelidae) based on mitochondrial DNA sequence. Molecular Phylogenetics and Evolution 29(3): 540–549.

Sibley, C.G. & Monroe Jr., B.L. (1990). Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven, Connecticut.