Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Biology (PhD)

Degree Level



Biological Sciences


Douglas James

Committee Member

Kimberly Smith

Second Committee Member

Steven Stephenson

Third Committee Member

John Hehr


Asia, Haliaeetus leucoryphus, Migration, Pallas's Fish Eagle


Pallas’s Fish Eagle (Haliaeetus leucoryphus) is the Northern Hemisphere’s least understood eagle species. Virtually nothing is known concerning the species’ ecology. Historically, Pallas’s Fish Eagles were expected to breed in three separate populations in Mongolia, China, and India and was considered one of the most common raptors in Asia prior to the 1900’s. However, by 1960’s major declines were observed. The species is currently listed as “globally vulnerable” by the International Union for the Conservation of Nature (IUCN) Red List. The current study examined over a century of Pallas’s Fish Eagle observation data to determine occupancy and detection rates throughout its range with hierarchical models. Results indicate a high probability of detection, but a low occupancy probability (<0.8). Three juvenile Pallas’s Fish Eagles were also tagged in India and Mongolia with 70 g GSM-GPS solar-powered, satellite transmitters to track their movements. The collected GPS data were used to determine home range sizes that averaged at 50 km2 and gather evidence of potential site-fidelity. Further, extensive, seasonal migrations of over 4000 km from India to Mongolia and Russia were observed in the spring and fall for all individuals with significant overlap in route and timing similarities. Tracked individuals also demonstrated a previously unknown capability to fly directly over the Himalayan Mountains at altitudes that exceed 6000 m. This study provided supporting evidence indicating that a majority of the migratory, global population of Pallas’s Fish Eagles is a single population, instead of three separate populations.