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Those who have been in recent years to New Guinea may have been lucky enough to see either Masked Bowerbird in the Arfaks of West Papua, or the closely related Flame Bowerbird in the southern lowlands of Papua New Guinea. The display behaviour of both species has been well-documented during recent BBC films (one of their hides we were even able to use on our tour a few years ago!), but myself and other bird tour leaders have regularly noted that there is an abnormally high incidence of males being seen destroying or otherwise abandoning their bowers.

Male bowerbirds are known to make their bowers at the start of the breeding season (usually over the course of days or weeks), and spend much of their time very close to their constructions to protect them from other males for the subsequent months. However at least these two species in the Sericulus genus can go for long periods of time without attending their bowers on any given day, perhaps to avoid predation due to their insanely vibrant colouration. It is also very common for the bowers to be "active" for a couple of days after a hide has been built, and then fall into disuse, this being especially true of Masked Bowerbird.

Last week, I was taken to a site in the Arfaks during our West Papua Vogelkop tour where the locals had found an active Masked Bowerbird bower several days previously. While no hide had been built yet, and there had been no disturbance to the bird, we arrived to find the bower already abandoned. The bower of presumably the same male was found later that day less than a hundred metres away, and we set up a very small hide overnight at a good distance from the construction. I was sitting very quietly in there at dawn, and observed a male come in and completely rip apart the entire structure in the span of about ten minutes before flying off. Was it the owner, so sensitive to disturbance that the mere sight of a nearby hide was enough to make him give up? I have seen Flame Bowerbirds do exactly the same thing, and this is an opinion often voiced by the local hide owners, but had always seemed a strange explanation to me.

An hour later, another male came in with an engorged tick on his face (proving he was a different individual, and this time seemingly the real owner). I watched in complete silence, and in slightly less than sixty minutes he had completely rebuilt the bower from scratch using the broken pile of twigs left lying on the ground. This single session in the hide was very enlightening, and indicated to me that perhaps it is normal for the males to regularly move the position of their bowers, especially since they can clearly rebuild much faster than I had imagined!

Later reading about the congeneric Regent Bowerbird of Australia (the only well-studied Sericulus bowerbird) surprisingly seemed to validate all these hypotheses. One comprehensive study (Lenz 1994) recorded adult males spending only 3.2% of daylight hours at their bower, with damage caused by intruders (both adult males and immature males) frequently leading to the abandonment of a bower by its owner. Lenz also observed rebuilds occuring an average of 64m away, usually finished within a matter of hours. What a contrast to most other species in the family!

All-in-all a very interesting field study of this spectacularly fascinating but still poorly-known New Guinea endemic, which certainly gives us some better information about how to improve our chances of a sighting on our future tours! He returned the following day and everyone else in the group saw him very nicely, even doing one short display to a female!

The owner of the construction, a male Masked Bowerbird (Sericulus aureus) which has almost finished rebuilding his destroyed bower. By Joshua Bergmark.

Whilst birding in a thickly-vegetated gully at about 1500m during the pretour scouting for our Bougainville expedition in September 2024, I accidentally flushed a bird which subsequently began making a strange trilling song. I guessed it was Bougainville Island-Thrush, a relatively common and only recently-split endemic species. I recorded the sound before hiding carefully and playing it back. For some time, the bird provided brief glimpses as it moved around in the understory, occasionally singing. Suddenly, it hopped onto a log only two meters in front of my face, almost close enough to touch, and I nearly fell over backwards. It was not a Bougainville Island-Thrush. It was a Bougainville Thicketbird!

This group of seldom-seen skulkers, which range from Timor to Fiji, can nonetheless be extremely inquisitive, and the Bougainville Thicketbird was no exception. After I had run down the mountain to find everybody else, we were treated to an absolutely amazing encounter with this lost bird (which had not been scientifically documented for more than 20 years) as it walked circles around us. Having a brand new sound recording proved key, and during the coming days we would find a total of five territories, and obtain the first photos of the bird in its natural habitat.

More details about this exciting discovery can be read at The Search for Lost Birds.

Bougainville Thickebird (Cincloramphus llaneae) by Joshua Bergmark

The enigmatic Moustached Kingfisher is an extremely poorly-known species, with no published records of the bougainvillei taxon by ornithologists or birdwatchers since 1928. The only photos which exist are of a mistnetted individual from Guadalcanal of the excelsus subspecies, taken in 2015, and a couple of phone photos depicting individuals captured by local villagers on Bougainville during the past decade.

Following a week of scouting in September 2024 for our Bougainville expedition, we located one pair in a gully at 1350m. The base of the gully had significant areas of open ground amongst tall wild banana plants. The male would sing (unprompted) only once or twice each morning between 06:00 and 06:30 in the predawn darkness. One one occasion, he was observed sitting 2m off the ground on a presumed hunting perch. Nearby, we came across a young bird which we guessed was less than one year old, showing slightly muted colours and a dark brown bill. Photos and recordings obtained by our group indicate quite substantial differences between the bougainvillei and excelsus taxons with regards to bill and belly colouration, plus a slower and more drawn-out song.

More details about this exciting discovery can be read at The Search for Lost Birds.

Male Moustached Kingfisher (Actenoides bougainvillei bougainvillei) by Joshua Bergmark

An interesting observation on our Brazil: Interior tour this month was a pair of Long-tailed Reed Finch hopping around on rocks and clambering in low vegetation at the top of the Pico da Lapinha Trail (where we search for the endemic Cipo Canastero). Tour participant Ohad Sherer took excellent photos which show some distinctive features, including a particularly dark face with otherwise rather faintly-marked plumage. I have seen what is probably this form on the top of Itatiaia National Park many years ago, also utilising this distinct habitat which is far from the usual reed beds almost exclusively preferred by this species further south. It seems to me a similar case to Speckle-breasted Antpitta and Slaty Bristlefront, both these also considered monotypic but with clear morphological and vocal differences from north to south. Further study required!

Long-tailed Reed Finch (Poephila acuticauda) from Cipo by Ohad Sherer

Last week, on the ferry crossing to Waigeo during our regular West Papua Vogelkop tour, I photographed an adult Nazca Booby. This was a completely unexpected first for Indonesia, New Guinea, and the south-west Pacific.

On our return to the mainland four days later, this same ferry crossing produced another (but more expected) confirmed first for West Papua, this being a Swinhoe's Storm-Petrel. We also photographed a near-certain Beck's Petrel (thanks fo Bob Flood for his comments), which would represent the first live sighting for West Papua after recent radiotracking results confirmed movement of this rare species into these same waters. Certainly some extremely productive ferry crossings!

Nazca Booby (Sula granti) offshore from Waigeo by Dani Lopez-Velasco

With a little bit of trailblazing, our Papua New Guinea: Islands tour group managed to find, photograph, and sound record the Mussau Triller during our recent 2024 departure. While a handful of sightings have been made in the previous decades, no scientific documentation has been produced since a specimen was collected in 1979!

You can read more about our time on the island at The Search for Lost Birds.

Male Mussau Triller (Lalage conjuncta) by Joshua Bergmark

With a bit of a website revamp, we now have a few pages up dedicated to explaining the strategy we use when designing itineraries in some of our favourite regions. Check them out at the below links!

www.ornis-birding.com

www.ornis-birding.com

www.ornis-birding.com