Priorities for Future Research

This species account illustrates the remarkable number of studies conducted on Golden Eagles and the depth of the knowledge about the species. However, data gaps still limit the ability to understand Golden Eagle ecology and to make appropriate management decisions. These knowledge gaps fall into several categories.

First, despite extensive research activity, there is substantial uncertainty about how Golden Eagle responds to factors such as climate change, urbanization, and the associated increase in human activity, energy development, wildfires, and other anthropogenic influences (604 Kochert, M. N., K. Steenhof, L. B. Carpenter, and J. M. Marzluff (1999). Effects of fire on Golden Eagle territory occupancy and reproductive success. Journal of Wildlife Management 63: 773–780. Close , 582 Kochert, M. N., and K. Steenhof (2002). Golden Eagles in the U.S. and Canada; Status, trends conservation challenges. Journal of Raptor Research 36 (supplement): 33–41. Close , 743 Leu, M., S. E. Hanser, S. T. Knick (2008). The human footprint in the west: a large-scale analysis of anthropogenic impacts. Ecological Applications 18: 1119–1139. Close , 628 Copeland, H. E., A. Pocewicz, and J. M. Kiesecker (2011). Geography of energy development in western North America: Potential impacts on terrestrial ecosystems. In Energy Development and Wildlife Conservation in Western North America (D. E. Naugle, Editor). Island Press, Washington, DC, USA. pp. 7–22. Close ). Many of these changes are occurring in the Golden Eagle range and may affect distribution patterns, nesting, productivity and mortality rates (474 Steenhof, K., M. N. Kochert, and T. L. McDonald (1997). Interactive effects of prey and weather on Golden Eagle reproduction. Journal of Animal Ecology 66: 350–362. Close , 582 Kochert, M. N., and K. Steenhof (2002). Golden Eagles in the U.S. and Canada; Status, trends conservation challenges. Journal of Raptor Research 36 (supplement): 33–41. Close , 682 Pagel, J. E., K. J. Kritz, B. A. Millsap, R. K. Murphy, E. L. Kershner, and S. Covington (2013). Bald Eagle and Golden Eagle mortalities at wind energy facilities in the contiguous United States. Journal of Raptor Research 47: 311–315. Close , 177 Paprocki, N., J. A. Heath, and S. J. Novak (2014). Regional distribution shifts help explain local changes in wintering raptor abundance: Implications for interpreting population trends. PLoS ONE 9: e86814. Close , 744 Paprocki, N., N. F. Glenn, E. C. Atkinson, K. M. Strickler, C. Watson, and J. A. Heath (2015). Changing habitat use associated with distributional shifts of wintering raptors. Journal of Wildlife Management 79: 402–412. Close ; see Conservation and Management: Effects of Human Activity: Degradation or Improvement of Habitat). Clarifying these areas of uncertainty is therefore an important priority.

Second, in the contiguous continental United States, extensive effort has been devoted to aerial surveys to estimate trends in abundance (587 Good, R. E., R. M. Nielson, H. Sawyer, and L. L. McDonald (2007). A population estimate for Golden Eagles in the western United States. Journal of Wildlife Management 71: 395–402. Close , 588 Millsap, B. A., G. S. Zimmerman, J. R. Sauer, R. M. Nielson, M. C. Otto, E. Bjerre, and R. Murphy (2013). Golden Eagle population trends in the western United States: 1968–2010. Journal of Wildlife Management 77: 1436–1448. Close , 589 Nielson, R. M., L. McManus, T. Rintz, L. L. Mcdonald, R. K. Murphy, W. H. Howe, and R. E. Good (2014). Monitoring abundance of Golden Eagles in the western United States: Golden Eagle abundance in the western U.S. Journal of Wildlife Management 78: 721–730. Close ). Continuation of these monitoring efforts is an important component of management for Golden Eagle conservation (622 U.S. Fish and Wildlife Service (2013). Eagle Conservation Plan Guidance. Module 1 Land-based wind energy, version 2. Division of Migratory Bird Management, Washington, DC, USA. Close ). However, these surveys exclude wide areas of the distribution of the Golden Eagle in North America, especially Alaska, Canada, and Mexico. Alaska and Canada in particular may hold as many nesting pairs of eagles as does the rest of the United States. No similar work has been done elsewhere in the global range of the Golden Eagle. As such, another priority is to identify ways to estimate demographic and ecological parameters for Golden Eagle and to monitor their populations, range-wide.

Finally, there is a great deal that we do not know about the biology of the Golden Eagle. Some noteworthy areas of uncertainty include:

• factors that influence population trends, especially the role of anthropogenic mortality and in identifying compensatory vs. additive mortality
• other aspects of demography, especially spatial and temporal variation in parameters such as age-specific survival and reproductive rates, and rates associated with movement (emigration, immigration, natal dispersal, breeding dispersal, age structure)
• population-level effects of environmental contaminants and habitat alteration on nesting, migrating, and wintering grounds
• size of the floating segment of populations and how non-territorial and territorial birds interact
• genetic structure of populations
• degree to which there is migratory connectivity of eagle populations and at what scale connectivity should be measured for eagles
• winter ecology, particularly, interactions between migrants and residents on winter grounds, the composition of wintering populations (migrants vs. residents), and the geographic origin and distribution of migrants in wintering populations.