Poor‐quality monitoring data underestimate the impact of Australia's megafires on a critically endangered songbird

Aim Catastrophic events such as south-eastern Australia's 2019/20 megafires are predicted to increase in frequency and severity under climate change. Rapid, well-informed conservation prioritization will become increasingly crucial for minimizing biodiversity losses resulting from megafires. However, assessments susceptible bias, because the quality of monitoring data underpinning knowledge species' distributions is highly variable they fail account differences life history traits aggregative breeding. We aimed assess how impact estimates on critically endangered regent honeyeater Anthochaera phrygia varied according available input assessment methodology. Innovation Using Google Earth Engine Burnt Area Mapping, we estimated using six datasets that differ temporal span. These representative assessing fire 326 other threatened species; most poorly monitored, few have standardized, species-specific programmes. found based area occupancy (AOO), extent occurrence (EOO) public sightings underestimated relative recent, targeted datasets: a MaxEnt model, national programme nest locations since 2015. an threshold 30% habitat burned, honeyeaters would not meet these criteria derived EOO, AOO or sightings, but exceed cut-off population density. Main conclusions To ensure has greatest capacity minimize losses, highlight need improve targeted, species monitoring. demonstrate importance standardized estimate accurately major ecological disturbances, particularly declining, nomadic undergoing range contractions.