We are interested in understanding species’ responses to environmental change. We make novel use of time-series available through museum collections and citizen science, with a particular focus on the effects of climate change on avian morphology. We work at a range of scales, from local, within-population dynamics up to continental-wide comparisons of different species in different climatic regions and regimes. We seek to understand the consequences of environmental change for the viability of populations: how climate drives changes in body size and shape, associated fitness costs for individuals and demographic consequences for populations. These factors ultimately determine the abundance and distribution of species so our work has a bearing on environmental management.