A bird nobody had named, in a forest nobody had surveyed

In the fragmented Andean woodland above Huanta, in Peru's Ayacucho region, a British researcher and a Peruvian project coordinator have found a bird whose song matches nothing in the books. Eustace Barnes and Fabian Fabricio Lema Rivera believe it belongs to the thornbird genus Phacellodomus — and to no species yet described.

Barnes, a researcher from the University of Cambridge, has spent much of his working life with Peruvian birds. He illustrated A Field Guide to the Birds of Peru, and has led birding tours across Peru, Chile and Venezuela. He knows what the country's 1,879 recorded species sound like. Lema Rivera coordinates the project from the Universidad Nacional Autónoma de Huanta, an institution younger than most of its students' school careers — created by law in 2011, licensed by Peru's regulator in 2017, the second public university in the country to clear that bar.

Their comparative analysis found both morphology and vocalisations that separate the bird from every known member of its genus. The two men announced the finding together, on behalf of a joint project between UNAH and Cambridge's Cavendish Laboratory, examining environmental systems and ecosystem services in the Huanta region.

Thornbirds are named for what they build. Phacellodomus joins the Greek words for a bundle of twigs and a house: their stick nests stand 35 to 60 centimetres tall on bare branches, assembled from sticks up to 60 centimetres long, with the entrance low on one side and a lined chamber inside. Some species add empty chambers that appear to serve no purpose except to confuse whatever comes hunting for the eggs. The nests are reused and enlarged season after season, and they are conspicuous — which means a thornbird can often be counted by its architecture rather than by sight.

That distance matters. The chestnut-backed thornbird, Phacellodomus dorsalis, is Peru's only endemic member of the genus, confined to some six known localities far to the north. Whatever is singing above Huanta is a long way from any of them.

There is a reason these slopes went unread for so long. Ayacucho is where Peru's internal armed conflict began in 1980, and where it fell hardest: the Truth and Reconciliation Commission attributed roughly 40 percent of the country's nearly 69,000 dead and disappeared to that one department, with Huanta among the worst affected provinces. Sustained biological fieldwork became routine here only after the violence subsided around 2000. The forest kept its secret because for twenty years nobody could safely go looking.

Barnes and Lema Rivera are now preparing the formal manuscript — diagnostic traits, geographic distribution, conservation status. That last item is the urgent one. The habitat where the bird was found is fragmenting as they write.