The north-east Gabon forest study gives field details for Xavier's Greenbul. Compared with P. icterinus at the same study area, it was larger, had a throat paler than its breast and a less vivid rufous tail. The study recorded it in the canopy and upper forest, feeding on insects.
In the study, it was described as larger overall than P. icterinus at the same locality. Female P. xavieri, however, were similar in size to male P. icterinus. Its throat was paler than its breast and its rufous tail less vivid.
At the Makokou/M’Passa study sites in north-east Gabon, it was recorded in the canopy and upper strata (about 15 m or higher) of primary forest, in pairs or small family groups, and feeding on insects.
An extinction-risk assessment has not been added yet.