The Black Tinamou (Tinamus osgoodi) is a rare and endangered bird with two geographically disjunct subspecies. Very little pertinent information exists due to its secretive habits and cryptic coloration. Observations from a one-year study at Alto Fragua Indi Wasi National Park in southern Colombia have provided new ecological information for T. o. hershkovitzi. This subspecies vocalizes mostly between March and April, suggesting that the breeding season occurs during the first half of the year. Detections by camera traps indicate that this tinamou is more active in late morning, a pattern also found in other lowland tinamous. The subspecies was found in the entire study area, but more commonly at middle altitudes (1,400–1,600 m). We estimated a density of 13.47 birds km−2, which is relatively high compared with the abundance of other tinamous of similar size. Despite the locally observed high density of this subspecies of Black Tinamou, high rates of logging and hunting in the area make this population vulnerable to rapid decline in the future.