A still from camera trap video footage of the black tinamou. Image: Pablo J. Negret

Meet the black tinamou, Tinamus osgoodi hershkovitzi, one of the world's rarest birds. It's the size of a chicken and lives in tall, dense forests on the hillsides of the eastern Andes in South America. More bluish-grey than black, it's a master at remaining out of sight, making it really hard to spot. For decades, the species languished in avian anonymity, but now a group of researchers has captured new video and audio of the birds, possibly the first ever recorded.

The team, led by ecologist Pablo Jose Negret from Colombia's Universidad de los Andes, walked along transects each day in search of the mysterious birds in Colombia's Alto Fragua Indi Wasi National Park. Whenever they found a black tinamou, they tried to record vocalisations (which really only occur during the breeding season in March and April). The researchers also set up a series of camera traps to take photos and record videos.

In all, they managed to observe 22 individuals, but it took nine months of effort before Negret even managed to snap a single photo of one. "The most challenging part of the fieldwork was the four to six kilometre walk along the transect's steep trails each morning, from 800 to 1,600 meters above sea level. However, these walks also gave me extraordinary moments like the observation of a Puma concolor [mountain lion] along the trail or the moment when I had the chance to photograph the elusive Tinamus osgoodi [black tinamou] after almost nine months of trying," said Negret in an official statement.

The information that Negret and his colleagues generated is quite basic compared to our knowledge of many other birds. Black tinamous are most active in late morning and eat mostly fallen fruits and seeds. They don’t migrate. In fact, they probably don't move around that much at all, except when the Amazon floods or when higher latitudes become too cold. The findings are described in The Auk: Ornithological Advances.

Because the bird is so hard to find, it's been considered a rare species. However, the researchers estimated a density of thirteen to fourteen individuals per square kilometre, which is higher than they suspected initially. Still, logging, ranching and hunting are all common activities in the area despite the steepness of the slopes and the protection afforded by the national park.

The black tinamous share an ecosystem with other species of conservation concern, like woolly monkeys, mountain tapirs, mountain lions and curassows – all species we know are affected by these human activities. And ecosystems are in some ways like a house of cards: who knows how human impacts on those others species might affect the elusive birds? "[M]ore detailed study of the true impact of these activities on the local fauna is imperative," the researchers conclude.