Dusky TetrakaXanthomixis tenebrosa
Malagasy Warblers (Bernieridae)
For many years, this semi-terrestrial songbird was a mystery in Madagascar, in large part because it wasn’t always clear how to separate it from a similar, related species. However, this all changed in 2022/2023, when it was rediscovered at two separate locations in the northeast! Recent encounters within lowland rainforest suggest it may prefer streamside haunts.
In December 2022 and January 2023, the Dusky Tetraka was rediscovered at two separate locations in northeast Madagascar (on the Masoala Peninsula and near Andapa, respectively). This was 23 years after the last specimen was collected (October 1999) at the same site as the January 2023 observation. Much more recently than that 1999 specimen, however, a pair was photographed attending a nest at Masoala National Park (Ambohitsitondroina), which seems likely to have been the most recent prior documentation for this species. That image, by Achille Raselimanana, is displayed in an unpublished report (Photo 40, page 66) from a biological assessment that took place between October and December 2015.
Raherilalao, M.J., Raselimanana, A.P., Soarimalala, V. and S.M. Goodman. 2016. Évaluation biologique de la flore et de la faune du Parc National de Masoala. Rapport non publié. Association Vahatra, Antananarivo.
- Cameron Rutt
- Search for Lost Birds
Mysterious songbird rediscovered in Madagascar after eluding scientists for 24 years
Cameron Rutt / 21 Apr 2023Read More
The Dusky Tetraka, a small olive-colored and yellow-throated bird that hops around on the ground and has eluded ornithologists for 24 years, was rediscovered by an expedition team searching the tropical forests of northeastern Madagascar. The expedition team, led by The Peregrine Fund's Madagascar Program, found the species in two different remote sites: one on the Masoala Peninsula in late December 2022 and another near Andapa in January this year. The last documented sighting of the Dusky Tetraka was in 1999, making it one of the top 10 most wanted lost birds by the Search for Lost Birds, a collaboration between American Bird Conservancy (ABC), BirdLife International, and Re:wild.
“Now that we've found the Dusky Tetraka and better understand the habitat it lives in, we can look for it in other parts of Madagascar, and learn important information about its ecology and biology,” said Lily-Arison Rene de Roland, Madagascar Program Director for The Peregrine Fund, and expedition leader. “There is a lot of biodiversity still to discover in Madagascar.”
Rene de Roland — who also rediscovered the Madagascar Pochard in 2006 in a remote area of northwestern Madagascar and was a student working with The Peregrine Fund when the Madagascar Serpent Eagle and Red Owl were rediscovered — spent several months searching for the Dusky Tetraka in Madagascar, the only place where it is found. He and his team set out in late December 2022 to search for the tetraka, a warbler-like bird that is part of a family found only in Madagascar, near Andapa. The team had to drive for more than 40 hours and hike for half a day up steep mountains to the last spot the bird had been seen. No ornithologists had returned to the site since 1999.
When the team arrived at the spot, they found that much of the forest had been destroyed and converted to vanilla farms even though the area is officially protected as part of the COMATSA Sud protected area. After five days of searching they decided to move to lower elevations, since they had not seen any sign of the bird and realized that the Dusky Tetraka might not live at higher elevations.
While Rene de Roland and his team were searching for the tetraka near Andapa, another team from The Peregrine Fund's Madagascar Program, led by Armand Benjara and Yverlin Pruvot, found the bird on the Masoala Peninsula where they caught and released a single Dusky Tetraka in a mist net on December 22. Benjara had been hoping to find the tetraka since he started working as a biologist for The Peregrine Fund.
“Seeing the bird for the first time was truly a surprise,” said Benjara. “Our entire team was extremely happy and excited.”
On January 1, eight days into the expedition, Rene de Roland's team got their first glimpse of a Dusky Tetraka. While next to a rocky river, John C. Mittermeier, Director of the Search for Lost Birds Program at ABC, finally saw a bird that matched the description of the Dusky Tetraka hopping around in dense undergrowth near the river and snapped a photo of it. After consulting with the rest of the team, they agreed it was the Dusky Tetraka and quickly moved the search to that area.
“If Dusky Tetrakas always prefer areas close to rivers, this might help to explain why the species has been overlooked for so long,” said Mittermeier. “Birding in tropical forests is all about listening for bird calls and so you naturally tend to avoid spending time next to rushing rivers where you can't hear anything.”
On the last day of the expedition, January 2, the team was able to capture one Dusky Tetraka using a mist net and observe and measure it more closely before releasing it unharmed. The two Dusky Tetrakas they found spent the majority of their time in dense vegetation close to the river, presumably looking for insects and other prey in the damp undergrowth.
The Dusky Tetraka has a history of mistaken identity largely because it closely resembles another, much more common species, the Spectacled Tetraka. With so few confirmed observations for the Dusky Tetraka, it has been difficult for ornithologists to compile the species' identifying characteristics. Ahead of the trip, the expedition team reviewed all the historical records of the bird dating back nearly a century to be sure they could positively identify the Dusky Tetraka if they found it.
Rene de Roland says the next steps for The Peregrine Fund's Madagascar team will be to look for the Dusky Tetraka again between September and October, when most birds in Madagascar breed. They hope to visit additional sites that match the habitat and elevation where they saw the species in December and January to understand its distribution and conservation status. With the vast majority of the lowland rainforest in northeastern Madagascar already destroyed, it is likely that the Dusky Tetraka is under threat.
The Search for Lost Birds looks for species that have not had a documented sighting in at least 10 years. It developed a list of the top 10 most wanted lost birds when it launched in 2021. The Santa Marta Sabrewing, another of the top 10 lost birds, was rediscovered in Colombia in July 2022 by Yurgen Vega, a biologist working with SELVA, ProCat Colombia, and World Parrot Trust in the Sierra Nevada de Santa Marta. The eight birds that have yet to be rediscovered are the Siau Scops-Owl in Indonesia, South Island Kōkakō in New Zealand, Himalayan Quail in India, Itombwe Nightjar in Democratic Republic of Congo, Cuban Kite in Cuba, Negros Fruit Dove in the Philippines, Vilcabamba Brushfinch in Peru, and Jerdon's Courser in India.
The rediscovery of a lost bird sparked an effort to find more species in Madagascar
Cameron Rutt / 5 Oct 2023Read More
For more than 20 years, scientists explored the forests of Madagascar in search of the Dusky Tetraka, a bird that is endemic to the country and one of the top 10 most wanted lost birds by the Search for Lost Birds, a collaboration between American Bird Conservancy, BirdLife International and Re:wild. There had been a few possible sightings of the Dusky Tetraka over the years, but the difficulty of identifying the species had left doubt about whether the bird had been found for certain, until a team, co-led by Lily-Arison Rene de Roland, executive director the Peregrine Fund’s Madagascar Program, Armand Benjara, a research scientist with the Peregrine Fund’s Madagascar Program, and John C. Mittermeier of American Bird Conservancy (ABC), rediscovered the species in Madagascar in late December 2022 and early January 2023.
“Rediscoveries are really important, but they can often lead to more questions that conservationists have about lost species or the areas where they are living,” says Christina Biggs, lost species officer for Re:wild. “We need more information in order to determine the next steps to protect a rediscovered species–which could be anything from, nothing because they’re doing fine, to creating protected areas to bolster critically low populations through ex-situ breeding programs.”
The rediscovery of the Dusky Tetraka served as the catalyst for a first-of-its-kind expedition by the Search for Lost Species that is about to get underway. In late August 2023, an expedition team will venture to the Makira forest, one of the largest and most intact rainforests remaining in Madagascar, searching for 30 species that are lost to science.
“When the original expedition started planning to visit Makira to potentially find more birds, we realized that there could be other lost species–not just birds, but reptiles, mammals, fish and insects–in the same area,” says Biggs. “We developed a plan to try and find as many of them as possible and invited herpetologists, ichthyologists, and entomologists. I’ll be conducting an environmental DNA study to support the findings of the many taxonomists on the expedition. It’s a really exciting next step for the Lost Species program.”
After spending months designing and planning the expedition, more than 15 conservationists and researchers from The Peregrine Fund’s Madagascar Project, Wildlife Conservation Society’s Madagascar Program, the University of Antananarivo, the University of Oxford, Biodiversity Inventory for Conservation (BINCO), Re:wild, and American Bird Conservancy will search for lemurs, fish, invertebrates and reptiles that have not had a documented sighting in at least a decade, though some have been lost for more than a century.
The expedition team is optimistic that lost species may still survive in Makira, but based on the rediscovery of the Dusky Tetraka, a search in a remote Malagasy forest is going to be anything but easy.
The journey in search of the Dusky Tetraka
When the Dusky Tetraka expedition team set out in December 2022, their journey involved gruelling hours on bumpy roads, long treks through rivers and harsh weather. To cover more ground, the expedition team split into two groups, targeting two different areas in Madagascar: Masoala and Andapa, where the team spent 14 and 9 days, respectively. Things set off quickly at Masoala where Benjara and his team spotted the tetraka on the very first day of the search there. At Andapa, the search stretched on for days, and eventually, on the last day of the search, Rene de Roland and Mittermeier caught sight of a Dusky Tetraka.
“We didn’t find any sign of the Dusky Tetraka for the first week that we were in the forest in Andapa," says Mittermeier. "Without any promising leads, it was hard to stay optimistic and I was seriously beginning to lose hope and doubt that we would have success finding the bird. Then, on our second-to-last day, we happened across two Dusky Tetrakas seemingly out of nowhere. It was amazing.”
Both search teams in Andapa and Masoala found the Dusky Tetraka near rocky rivers at mid-elevation, a habitat consistent with previous sightings. If the Dusky Tetraka is in fact a specialist in this type of habitat, that may help explain why it has been so rarely recorded.
“Part of the reason it could have been overlooked is because when you’re bird watching, areas next to rushing rivers are actually a habitat that you tend to avoid,” explains Mittermeier. “It is harder to see and hear birds next to rushing rivers so you instinctively tend to spend time on ridges and areas where it is easier to see and hear. Another possibility contributing to the Dusky Tetraka’s elusiveness could be that the specific habitat the species prefers is not present around the popular birding sites in Madagascar. People often tend to go to the same spots again and again which could contribute to the tetraka getting overlooked.”
Rene de Roland also highlights that the bird has eluded scientists for years due to its similar colour to that of the surrounding rocks. This camouflage has kept the bird hidden in plain sight.
Deforestation, a threat to species in Madagascar
While scientists still know very little about the Dusky Tetraka and its preferred habitats, it seems very likely the species is threatened by deforestation and habitat loss. The majority of lower and mid-elevation forest in northeastern Madagascar has been cleared, likely leaving very limited habitat for the tetraka and other species that live in that type of forest. Due to the ongoing habitat destruction, there's a pressing need to study the tetraka and other species before the habitat is lost forever.
"We had the coordinates of the last observation in 1999, and when we went to this place, it had been destroyed and burned to clear for agriculture,” says Rene de Roland. “Vanilla cultivation is very popular around Andapa and is a big problem for the forest there."
The race to beat the clock
“This is a bird that was one of the most poorly known bird species in Madagascar and is listed as data deficient on the current IUCN Red List,” explains Mittermeier. “There are only a handful of species in the world that are currently listed as data deficient. The fact that the tetraka is one of those really highlights how very little we know about it.”
Since the rediscovery of the Dusky Tetraka, some members of the expedition team have revisited the areas where it was rediscovered in preparation for the upcoming expedition in Makira. The ornithologists on the expedition team intend on carrying out a targeted search for the tetraka in Makira forest, which is west of the Masoala peninsula and south of Andapa. If the expedition finds the Dusky Tetraka in Makira, it would mean it is more widely distributed and provide valuable insights into the conservation status of the bird.
Timing a search for dozens of lost species
The breeding season for most species in Madagascar spans from September through January, making September the optimal window for the follow-up expedition and to search for them.
With 30 species to search for, the specialists on the expedition team will use as many cutting-edge tools as possible to find any traces of each species as quickly as they can.
The ichthyologists on the expedition will be searching for three fish species. They’ll try and catch fish using nets and electrofishing before releasing the fish unharmed. (Electrofishing is a technique where scientists send an electric pulse in the water that is specially calibrated to only stun a specific species of fish. If the species is in the area, the scientists can easily catch it, take data on it and then release it unharmed.)
Entomologists will use light traps, Malaise traps (traps that look like tents and attract flying invertebrates), and search leaf litter and plants in hopes of finding 12 different insect species and 5 spider species.
Several members of the expedition team will be looking for mammals: the Masoala Fork-marked Lemur, which hasn’t had a documented sighting since 2004, the Madagascar Slit-faced Bat which has been lost to science since 1910, and Ellerman’s Tuft-tailed Rat which hasn’t had a documented sighting since 1969.
The ornithologists on the expedition team will be focused on finding the Dusky Tetraka again. Beyond obtaining more information about the distribution and conservation status of the tetraka, the team also hopes to learn more generally about the species, if they can find it. That data will be critical for conservationists tasked with designing strategies to protect the Dusky Tetraka.
"The next important thing is to know its ecology and biology as we need to conserve this bird," says Rene de Roland. "It will be interesting to know its biology and to learn more about this species from this next breeding season before the forest is degraded."
The sound recordings of the tetraka obtained during the previous expedition coupled with the insights into its preferred habitat, will hopefully give the team the upper hand on this next expedition.
The larger expedition won’t only rely on physically catching animals or getting a glimpse of them alone to determine if the lemurs, bats, reptiles, insects and fish are living in Makira forest. Researchers will also take environmental DNA samples from Makira forest’s rivers, streams and wet soil and analyze the samples in a lab. If scientists find a match for any of the 30 species they are looking for, they’ll know that even if they didn’t see an animal, the species is still in Makira.
"It's so incredible to have this larger team that we can potentially look for, not just the tetraka, but other lost species and perhaps discover new species as well," says Biggs.
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