Unexpected bat entrapment in a wall-mounted mail holder in southwest Western Australia

I report an incidental mortality event involving 10 bats found within a wall-mounted mail holder in the Northern Jarrah Forest, Western Australia. The purpose of this note is to document the event and highlight the potential hazard posed by this type of structure. Eight individuals were deceased, including seven male Southern Forest Bats Vespadelus regulus and one male Chocolate Wattled Bat Chalinolobus morio, while two bats were alive and released. This observation illustrates a simple and likely under-reported anthropogenic trapping hazard associated with smooth-sided artificial structures. Documenting such incidents may assist in identifying and mitigating small-scale but preventable sources of bat mortality.