Relating to or characterized by the study of avifauna; of or pertaining to ornithological collections or analysis.
From 'avifauna' + suffix '-istic' (relating to or characteristic of), following the pattern of creating adjectives that denote a style or approach to study.
An 'avifaunistic study' is a fancy way of saying researchers collected and analyzed all the bird species in an area—it's the kind of term that sounds impressive but really just means 'bird inventory.'
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