If we examine the names of the Orders of Birds, we find that they are in Latin, […] We might venture to anglicize the terminations of the names which Cuvier gives to the divisions of these Orders: thus the Predators are the Diurnals and the Nocturnals; the Passerines are the Dentirostres, the Fissirostres, the Conirostres, the Tenuirostres, and the Syndactyls: the word lustre showing that the former termination is allowable.
Source: wiktionary