Extreme ecological disturbances, such as floods, droughts, heatwaves, and wildfires, have increased in frequency and intensity under anthropogenic climate change, and this is projected to continue in the coming decades. The responses of nomadic species to these events are largely unknown. The Australian 2019/2020 ‘Black Summer’ megafires burnt a substantial proportion of the range of the highly nomadic grey-headed flying-fox (Pteropus poliocephalus). Here, we examine the foraging habitat utilisation of P. poliocephalus in response to this extreme disturbance event by comparing continental-scale telemetry datasets of pre- and post-fire foraging locations from large samples of flying-foxes tracked before (2012-17) and after (2022-24) the 2019/20 megafires. We performed a spatial overlay analysis of foraging locations with static maps of the burnt area and foraging habitat characterised by resource quality (productivity-reliability scores) and coverage (fractional cover). Tracked flying-foxes preferentially visited higher-quality foraging habitats that were generally of higher coverage; yet these habitats were disproportionately burnt by the megafires, despite their already limited areal availability. Subsequent to the megafires, we observed a population-level redistribution of foraging visits to unburnt, lower-quality, lower-coverage foraging habitats, including those in inland areas rarely visited previously. The extreme mobility of P. poliocephalus enhances its resilience to the impacts of widespread habitat disturbance caused by megafires, but the observed shift in foraging habitat utilisation to more marginal foraging habitat suggests an overall negative impact of the disturbance on the population. It is unclear whether these marginal habitats provided sufficient resources to support the population following the megafires. Incorporating dynamic environmental data, alongside population monitoring data, is needed to provide a more precise assessment of the impacts of widespread ecological disturbances on P. poliocephalus and other highly nomadic species to inform specific interventions needed to enhance the resilience of these species in a changing climate.