Leveraging genomics to understand threats to migratory birds

Understanding of how risk factors affect populations across their annual cycle is a major challenge for conserving migratory birds. For example, disease outbreaks may happen on the breeding grounds, the wintering grounds, or during migration, and are expected to accelerate under climate change. The ability to identify the geographic origins of individuals impacted, especially outside of breeding areas, might make it possible to predict demographic trends and inform conservation decision making. However, such an effort is made more challenging by the degraded state of carcasses and resulting low quality of DNA available. Here we describe a rapid and low-cost approach for identifying the origins of birds sampled across their annual cycle that is robust even when DNA quality is poor. We illustrate the approach in the common loon (Gavia immer), an iconic migratory aquatic bird that is under increasing threat on both its breeding and wintering areas. Using 300 samples collected from across t...