Understanding and managing migratory animal populations requires knowing what’s going on with them during all stages of their annual cycle—and how those stages affect each other. The annual cycle can be especially difficult to study for species that breed in the Arctic and winter in South America. A new study from The Condor: Ornithological Applications tackles this problem for Semipalmated Sandpipers, historically one of the most widespread and numerous shorebird species of the Western Hemisphere, whose populations in some areas have undergone mysterious declines in recent years.