'avifauna' originates from New Latin/modern scientific coinage, specifically combining the Latin word 'avis' meaning 'bird' and the Latin-derived 'fauna' meaning 'animal life'.

'avifauna' was coined in scientific usage (New Latin/English) in the 19th century by combining 'avis' + 'fauna' and entered modern English largely unchanged as 'avifauna' (plural 'avifaunas').

Initially, it meant 'the bird life (collective of birds) of a particular place or time', and over time it has retained this specific meaning in ecological and zoological contexts.