Scientists on the Trail of One of the World’s Rarest Birds Are Treated to a Special Show

Somewhere between one and 49: That’s how many adult Stresemann’s Bristlefronts are thought to be left in the world.

These figures weren't pulled out of a hat. They’re based on meticulous searches and a decades-long effort to study the bristlefront in its scant Brazilian range. Now, those labors have paid off with an encounter with a chatty female bird, renewing scientists’ hopes that the species—and its extraordinary, endemic-rich habitat—is hanging on.

Since the 1800s, the Stresemann’s Bristlefront has been an ornithological mystery. Only a few museum specimens have been collected from the seaside state of Bahia, Brazil, and wild sightings have been erratic, resulting in little information on the species’ behaviors and needs. The reason is twofold: On top of being rare and endemic, the bird is also extremely tough to detect. With its sooty and umber feathers and cryptic habits, the bristlefront is part of the hard-to-see, hard-to-ID tapaculo family. Think of the tapaculos as the avian equivalents of rodents; they can be as wily and skittish as a house mouse or meadow vole.

So, when a lone Stresemann’s Bristlefront was photographed in the 1990s, scientists sprang into action. They combed the dense rainforests of eastern Brazil until finally in 2004 they uncovered three individuals in Minas Gerais, the state just inland of coastal Rio de Janeiro.

The discovery convinced experts that conservation action was needed to keep the species from winking out completely. Given how confined it is to the Atlantic Forest, a biome that holds 20,000 types of plants and 50 percent of Brazil's tree diversity, the local nonprofit Fundação Biodiversitas decided to create a reserve to buffer the bristlefront from encroaching soy farms and loggers. The group teamed up with the American Bird Conservancy (ABC) to buy hundreds of acres of habitat from private landowners and create the Mata do Passarinho, or Forest of Songbirds. Soon after in 2010, the species was deemed critically endangered by the International Union for Conservation of Nature.

Things were going well with the reserve. It swelled to 2,352 acres as ABC struck land deals in the area, and in 2013 Brazilian researcher Alexander Zaidan de Souza found an active bristlefront nest on the property. But in early 2016 the unthinkable happened: A wildfire hit the main site where the birds had been first observed. Subsequent searches turned up nothing, Zaidan de Souza says, save for an unsuccessful breeding pair in 2016.

With the existence of the Stresemann’s Bristlefront at stake again, ABC raced to raise funds for a new survey slated for July to December of 2018. Zaidan de Souza, who by then was managing the Mata do Passarinho, remembers those six months as being some of the “most intense field work and physical effort” he’s experienced. 

July passed, then August, then four more months without a single bristlefront sighting. As the New Year loomed, Zaidan de Souza feared the worst. “After so much effort and no results, it’s normal to have negative thoughts,” he says. But on December 12, Amy Upgren, an officer with the United Nations-funded Alliance for Zero Extinction, who was coordinating the search, received an early-morning message from her field mate. Instead of the expected routine update, the message read:

“We found the needle.” 

Not only had they found the needle in the haystack—a female bristlefront in this case—they’d also re-sighted it multiple times near the reserve and gotten a clear recording of it calling through the undergrowth.

Recording courtesy of Fundação Biodiversitas

It may seem like a lot of pain for a small gain, but a brush with even a single bristlefront can be pivotal to the species’ future. A displaying female, for example, means that the population has reproductive potential, which could help conservationists fight for better protective measures. Likewise, the audio and video help to raise public awareness and spur activism around the little-known species. 

What’s more, the status of the “rarest bird on Earth,” as Upgren puts it, ultimately reflects the health of the Atlantic Forest, which is down to 8 percent of its original breadth. The Stresemann’s Bristlefront’s existence is therefore entwined with that of its neighbors, the Pin-tailed Manakin, the Seven-colored Tanager, the Banded Cotinga, the maned three-toed sloth, and the yellow-breasted capuchin monkey; it’s the inspiration behind Mata do Passarinho and will continue to be its champion.

Currently, Fundação Biodiversitas and ABC are working on a strategy for the Brazilian government to protect the bristlefront’s habitat on a grander scale. Zaidan de Souza, meanwhile, has already commenced the hunt for the next “needle.” He’s determined to not let the bristlefront disappear from our conscience, even if it slips out of view for another months-long spell.