Traditional ecological knowledge (TEK) rigorously collected in four Key Biodiversity Areas (KBAs) of Samoa provided conservation and ecological insights about the endemic and evolutionarily distinctive Tooth-billed Pigeon Didunculus strigirostris. This study confirmed the 2006 estimate of a sharply declining population, supporting the recent conservation status assessment of Critically Endangered. Birds are killed as bycatch during hunting for the sympatric Pacific Pigeon Ducula pacifica, suggesting that this activity may be a key threat. The Tooth-billed Pigeon was observed by selected reliable indigenous hunters in several forest areas targeted in the present study, from a few months to several years ago. In the field, it was detected acoustically and identified through TEK and a mix of a TEK-scientific approach in four forest areas within three Samoan KBAs. Detection of the bird in the field is an issue due to its highly cryptic behaviour and because its call largely overlaps with one of the calls of Pacific Pigeon. Original TEK about the behavioural ecology of this species, including the fruiting trees mostly used and its terrestrial habits is reported. Short-term conservation recommendations are provided based on the findings.