Ecology and Conservation of Common Terns (Sterna hirundo) Breeding in the North American Great Lakes Region

• Main Author: Bracey, Annie
• Format: Thesis
• Language: English
• Published: 2021
• Subjects: common tern; conservation; integrated population model; mercury; metapopulation dynamics; solar geolocators; Niemi; Western Lake; Common tern; Sterna hirundo
• Online Access: https://hdl.handle.net/11299/241357

University of Minnesota Ph.D. dissertation. 2021. Major: Conservation Biology. Advisors: Francesca Cuthbert, Gerald Niemi. 1 computer file (PDF); 174 pages. The common tern (Sterna hirundo) is a long-distance migratory waterbird that breeds in both freshwater and marine environments in many parts of the world. Although the most wide-spread tern species in North America, populations have experienced extreme fluctuations during the last half century, with significant declines documented in the Great Lakes region and other inland breeding sites. Because of their reliance on coastal habitats, population declines have often been attributed to direct and indirect effects of human activity, such as habitat loss, modification, and degradation. In the Great Lakes most active breeding colonies occur at managed sites. The goal of my dissertation research was to document population dynamics of common terns breeding in western Lake Superior to understand how movement and demographic parameters vary between colonies and among colonies outside the region. A variety of intrinsic and extrinsic tagging methods were used to follow individuals throughout their annual cycle to identify potential risks to survival and fitness. Each chapter identifies potential risks to the population at different life stages and at different spatial and temporal scales. The first chapter documents large-scale movement patterns of adults breeding in the ‘central population unit’ using solar geolocation tracking devices to identify important migratory routes and wintering locations. Chapter 2 examines how adult foraging behavior influences mercury exposure in adults and chicks, to estimate exposure risk for birds nesting in western Lake Superior. Chapter 3 uses 36 years of mark-recapture data to identify drivers of population change by estimating survival, fecundity, and local-scale movements of adults and juveniles in western Lake Superior. These results filled gaps in knowledge about basic life history of Great Lakes nesting Common Terns and ...