This small sunbird is recorded in miombo woodland. A 2014 paper treats C. gertrudis as a species distinct from C. manoensis and reports differences in male plumage and nesting material.
In the paper's comparison, male C. gertrudis is more brilliant green, with a relatively narrower red breast band and longer, more profuse yellow pectoral tufts.
At study sites in Zambia the bird was recorded in well-developed miombo woodland; most reported nests were hanging structures made from Usnea lichen.
An extinction-risk assessment has not been added yet.