Airborne Environmental DNA Analysis as a Tool to Monitor Live Bird Trade

Abstract

The global trade in live birds is extensive, involving both international exports and large-scale domestic trade. Despite international regulations, trade in some CITES-listed species remains largely undocumented and illegal. Songbird markets are difficult to monitor, and conventional surveys are constrained by limited taxonomic expertise and deliberate concealment of illegally traded species. Here, we explore airborne environmental DNA (eDNA) analysis as a novel tool to detect avian species and assess its potential for monitoring bird trade. We collected airborne samples in both enclosed and open market environments, accompanied by visual surveys, and processed them using DNA extraction and metabarcoding to identify avian taxa. In enclosed settings, three of six present species were consistently detected across all sampling days, with the remaining three likely detected but assigned to closely related species, demonstrating high accuracy under controlled conditions. In open markets, eDNA analysis captured approximately 20% of visually observed species with available reference sequences, and detection probability increased with species abundance. A key limitation was the large proportion of amplicon sequence variants (ASVs) that could not be assigned to species, emphasizing the need for expanded reference databases and the use of multiple primers to improve detection. Despite these challenges, our results indicate that airborne eDNA analysis can complement conventional monitoring, particularly in enclosed trade contexts such as cargo containers. While open market applications face methodological constraints, further refinement and integration with conventional surveys could enable scalable, non-invasive monitoring of traded bird biodiversity.