An invasive prey and changing climate interact to shape the breeding phenology of an endangered predator.

Changes in phenology are occurring from global climate change, yet the impacts of other types of global change on the phenology of animals remain less appreciated. Understanding the potential for synergistic effects of different types of global change on phenology is needed, because changing climate regimes can have cascading effects, particularly on invasive species that vary in their thermal tolerances. Using 25 years of data from 5963 nests and 4675 marked individuals across the entire US breeding range of an endangered predator, the snail kite (Rostrhamus sociabilis plumbeus), we isolated the effects of an invasion of novel prey and warming temperatures on breeding phenology and its demographic consequences.