Fluvioviridavis nazensis was a small early strisorean belonging to the extinct Fluvioviridavidae. Its skeleton documents a branch of the broader nightbird and swift radiation that retained its own distinctive combination of wing and pectoral anatomy rather than the specialisations of modern nightjars or swifts.

It was fully volant and likely took small animal prey, with insectivory a reasonable inference. Whether it hunted continuously in the air, sallied from perches or used another strategy is not known. Several associated skeletons provide a better anatomical basis than is available for many historical London Clay bird names.