Ornithologists have discovered a new species of tinamous living in the mountain forests of the Serra do Divisor, western Amazon, Brazil.
Man from Resonance of Tinamou in Morro Queimado, Serra do Divisor National Park, Mancio Lima, Acre, Brazil. Image credit: Luis A. Morais.
“Genus Answered includes a small forest tinamus and is the most diverse in the family. Tinamideswith 21 recognized species,” said lead author Dr. Luis Morais from the Federal University of Rio de Janeiro and colleagues.
“Despite its diversity, Answered remains one of the least studied groups of birds in the Neotropics, largely due to its cryptic lifestyle and the inaccessibility of the dense forest habitats it occupies.”
“Western Amazonia is home to the greatest diversity Answered species occurring in the same region.”
“However, few studies have addressed tinamous taxonomy in this area, leaving several important questions unresolved.”
Researchers first recorded the new species' distinctive vocalization in 2021 in the undergrowth of the Serra do Divisor, an isolated mountain complex located on the border between Brazil and Peru.
“The song was reminiscent of songs AnsweredHowever, at that time, no species could be confidently identified and no visual confirmation was obtained,” they explained.
“Comparison with everyone Answered vocalizations known in the region, as well as consultations with ornithologists experienced in Amazonian avifauna, could not produce a convincing match.”
“This song is unlike any known tinamou vocalization, prompting the hypothesis that it may represent an undescribed form.”
In 2024, scientists were able to attract two individuals using digitally synthesized reproductions of earlier recordings, obtaining excellent views and photographs of one bird.
“During a field expedition to the Serra do Divisor National Park, five recognized species Answered were discovered: Tinamus Bartletty, Tinamous Gray, Tinamus Sui, Tinamus strigulosaAnd Tinamus variegatus“, they said.
“All of these species have been recorded in lowland forests and along lower mountain slopes.”
“In contrast, the only representatives of the genus encountered at higher mountain elevations, above 250 m, were specimens representing the taxon considered here as an undescribed species, exhibiting a unique combination of plumage coloration and vocal structure, which we formally refer to as: Resonance of Tinamou (a common name is shale mask tinamou).”
Over the course of ten independent sightings at eight locations in the mountainous Serra do Divisor region, the authors confidently identified at least 15 individual individuals.
“Given the total extent of suitable habitat within the defined altitudinal range (63,302 ha), we estimate the preliminary population size in the Serra do Divisor mountain complex to be approximately 2,106 individuals,” they said.
Resonance of Tinamou features a unique combination of plumage pattern, vocal repertoire, and environmental characteristics, including a prominent dark slate facial mask, bright rufous-cinnamon underparts, and uniform brownish-gray back.
“This species is distinguished from all other Tinamidae by the presence, at least in the females (the three sexed individuals were females), of a characteristic dark slate crown that extends into a conspicuous stripe down the rear neck and into the postocular region, forming a conspicuous facial mask,” the ornithologists said.
Vocalizations Resonance of Tinamou are notable for the fact that they consist of long and powerful songs that echo strikingly along the steep mountain slopes, producing a characteristic resonant effect.
“Resonance of Tinamou it was recorded to vocalize spontaneously in the afternoon and dusk, between 17:40 and 18:30 local time,” the researchers said.
“Its song is loud and travels long distances, but undergoes noticeable acoustic diffusion along the steep slopes of the Serra, which changes the temporal structure of the song due to echoes.”
“When confronted directly, the individuals did not exhibit avoidance behavior and appeared surprisingly tame, apparently not recognizing humans as potential predators.”
“In addition, individuals have been observed to move slowly and without signs of vigilance through open areas of the understory, which contrasts with the typically wary response of other tinamous.”
“Between vocal responses, the birds were also observed foraging on the forest floor, probing and turning over leaf litter with their beaks in search of food.”
According to scientists, Resonance of Tinamou may be very vulnerable to climate change and proposed infrastructure projects in Brazil.
“Opening Resonance of Tinamou highlights the biological uniqueness of the Serra do Divisor, strengthens its status as a center of mountain endemism and highlights the critical importance of maintaining its long-term conservation,” they concluded.
Their paper published on December 2, 2025 in the magazine Zootaxa.
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Louis A. Morais etc.. 2025. New look Answered (Aves: Tinamiformes) from the western Amazon, Brazil. Zootaxa 5725(2); two: 10.11646/zootaxa.5725.2.6
