It is known from a partially articulated fossil skeleton found in the Gobi Desert in Mongolia.

The fossil was collected at Togrogiin Shiree, South Gobi Aimak, Mongolia; Djadokhta Formation, Late Cretaceous, Campanian.

Chiappe et al. (2007) conclude from the proportions of Elsornis ' pectoral skeleton that it was flightless or nearly so.

However, if this is not the case, it may have hunted on the ground, snatching up small vertebrates and bugs.

Like the other members of Avisauridae, it probably had small non-serrated teeth it used for hunting, and possibly scavenged the carcasses left by other, more formidable carnivores.