<p>We described the foraging behavior, nest architecture, and the influence of abiotic factors in <i>Ptiloglossa pretiosa</i>, from a fragment of Atlantic Rainforest in southeastern Brazil. Females showed a bimodal activity pattern, with a primary peak at dawn and a shorter period at dusk. The number and duration of trips with and without pollen loads did not differ significantly. Soil was predominantly composed of clay, and nests consisted of a straight main tunnel with lateral branches and brood cells provisioned with liquid pollen–nectar mixtures. Light intensity and humidity significantly predicted foraging frequency. These results reveal a combination of traits widely shared within Diphaglossinae, as well as unique aspects of the natural history of this species.</p>