Golden eagles (Aquila chrysaetos) are large, long-lived raptors that feed on grouse, small mammals (e.g., rabbits, marmots, and ground squirrels), and carrion. Across the western USA, and in Wyoming in particular, there are growing concerns about the status of golden eagle populations due to broad-scale energy development (wind, gas) and increasing human activity. To better understand the current population status and the drivers of population trends across the ecosystem, park biologists began focused study of golden eagles in Yellowstone in 2011.
Surveys located 28 golden eagles territories inside the park, 20 within the northern range alone. The resulting density in northern Yellowstone (one territory per 49.7 km2) is relatively high. Likewise, territory occupancy rates from 2011 to 2018 have been consistently high (100%). In contrast, low average productivity at these nests (0.36 young/occupied territory) is driven by both infrequent nesting attempts and low nest success. For example, in 2018, researchers monitored 22 occupied territories; 9 pairs nested and 6 nests were successful in fledging 7 young. With such low productivity, the Yellowstone golden eagle population may be dependent on outside immigration, although much about the status of the park’s golden eagle population remains unknown.
In other studies, reproductive failure of eagles and other raptors has been correlated with weather (e.g., high failure in high precipitation years), often inter-acting with food availability. Ongoing research is investigating golden eagle habitat use in Yellowstone’s northern range to better understand local population dynamics.
In response to broad concerns about golden eagle populations, Wyoming has initiated a golden eagle working group and the US Fish and Wildlife Service has instituted a western US study modeling eagle habitat suitability, human development risks, lead exposure, and large-scale movements. Better under-standing of the ecology of Yellowstone National Park eagles requires study of their food habits, toxicology, survival, and movement both within and outside the park. In recent years, extensive data relating to these key topics have been collected in two study areas flanking the park to the north and east and complimentary research within the park is ongoing.
1940. Bald Eagle Protection Act of 1940 In 16 US Code 668- 668d, 54 Stat. 250.
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Last updated: August 20, 2019