BOU Annual Conference. We are living through a period of major environmental change at both local and global scales. Many species are declining sufficiently rapidly to be of serious conservation concern, yet others are proliferating, some to the point of being invasive. These rapid changes are being replicated in most of the globe’s avifaunas. Developing effective responses to these spatio-temporal changes requires scientists and policy makers to recognise the need not just to monitor them, but to understand the demographic mechanisms underpinning them. Critically, it is essential that our predictive capacity is improved by developing tools that enable the demographic consequences of potential management action to be quantified.