The status of golden eagles (Aquila chrysaetos) in coastal southern California is unclear. To address this knowledge gap, the U.S. Geological Survey (USGS) in collaboration with local, State, and other Federal agencies began a multi-year survey and tracking program of golden eagles to address questions regarding habitat use, movement behavior, nest occupancy, genetic population structure, and human impacts on eagles. Golden eagle trapping and tracking efforts began in September 2014. During trapping efforts from September 29, 2014, to February 23, 2016, 27 golden eagles were captured. During trapping efforts from February 24, 2016, to February 23, 2017, an additional 10 golden eagles (7 females and 3 males) were captured in San Diego, Orange, and western Riverside Counties. Biotelemetry data were collected between November 22, 2014 and February 23, 2016. Biotelemetry data for 26 of the 37 golden eagles that were transmitting data from February 24, 2016, to February 23, 2017 are presented in the reports. These eagles ranged as far north as northern Nevada and southern Wyoming, and as far south as La Paz, Baja California, Mexico.
For more information on this study, please visit the USGS website: https://pubs.er.usgs.gov/publication/ds994 .
SDMMP_2025_574604 Golden Eagle (Aquila chrysaetos) Management and Monitoring
Golden eagle
San Diego Association of Governments
Robert N. Fisher
U.S. Geological Survey
Robert N. Fisher
Sarah McCutcheon
Kris Preston
Jeff Tracey
Goal: Expand and then maintain a self-sustaining golden eagle population to ensure long term persistence (>100 years) on Conserved Lands in the MSPA by: improving reproductive success through protection of active and inactive nest sites from human disturbance; reducing anthropogenic mortality; managing large mosaics of grassland and open shrublands for optimal prey availability, especially during drought; and by minimizing human impacts to foraging eagles.
Management units: 3, 4, 5, 6, 8, 9, 10, 11
From 2017 to 2019, continue the Golden Eagle Nesting, Foraging, and Habitat Use Study, begun in 2014, to monitor golden eagle territory occupancy and reproduction in the MSPA (see occurrence table) and to track eagle movements to identify important foraging, nesting and roosting areas. Continue to study the influence of human activity and land use on patterns of eagle movement and habitat use, measure the response of eagles to human activity while foraging, and determine whether locally produced floaters recruit into the breeding population.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| RES-1 | Monitor territory occupancy and reproduction in suitable golden eagle habitat within the MSPA. Identify any threats or disturbance to eagles and provide this information to land managers so that management actions can be taken to reduce impacts from human disturbance and other threats. | in progress | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California |
| RES-2 | Capture adult eagles at selected territories and attach GPS-transmitters that track eagle movements to identify important foraging areas and to study movement patterns relative to human activity within a landscape matrix of urban, rural, and undeveloped lands. Determine whether eagles switch territories and mates, document individual mortality, and track emigration or short term movements outside of the MSPA. Determine if there are multiple nesting sites within a territory and identify nest sites that are unstable or vulnerable to loss. | in progress | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California , Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California |
| RES-3 | Analyze golden eagle foraging habitat data and develop objectives with criteria for managing open areas (grasslands and suitable areas in coastal sage scrub and chaparral) to conditions preferred by foraging eagles and that support abundant prey (e.g., black-tailed jack rabbits, ground squirrels). | unknown | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California |
| RES-4 | Measure eagle behavioral responses to human activity at foraging areas. Identify the intensity and type of human activity that affects foraging behavior. | in progress | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California , Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California |
| RES-5 | Use the GPS and behavioral response data to model potential impacts to foraging eagles under different scenarios of human disturbance at important foraging areas. Prepare management recommendations to reduce human impacts on foraging eagles, including alignment of trails, restriction of activities, and educational outreach. | in progress | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California , Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California |
| RES-6 | Submit project metadata, datasets, and report with management recommendations to the MSP Web Portal. | in progress | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California , Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California |
| Criteria | Deadline year |
|---|---|
| Golden Eagle Nesting, Foraging, and Habitat Use Study Report with Management Recommendations Completed by 2020 | 2021 |
| Threat Name | Threat Code |
|---|---|
| Altered fire regime | ALTFIR |
| Human uses of the Preserves | HUMUSE |
| Pesticides | |
| Urban development | URBDEV |
Goal: Expand and then maintain a self-sustaining golden eagle population to ensure long term persistence (>100 years) on Conserved Lands in the MSPA by: improving reproductive success through protection of active and inactive nest sites from human disturbance; reducing anthropogenic mortality; managing large mosaics of grassland and open shrublands for optimal prey availability, especially during drought; and by minimizing human impacts to foraging eagles.
Management units: 3, 4, 5, 6, 8, 9, 10, 11
From 2017 to 2019, continue the Golden Eagle Genetics Study begun in 2014 and collect genetic samples in conjunction with eagle captures for the Golden Eagle Nesting, Foraging, and Habitat Use Study. Analyze these samples to determine the population genetic structure of golden eagles within the MSPA (see occurrence table) and their relationship to eagle populations in other parts of the western United States.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| RES-1 | Collect blood samples from captured birds to include in a larger study of golden eagle population genetics in the western United States to determine the population genetic structure within the MSPA. Genetic parameters that can be measured include gene flow between territories, relatedness of individuals, effective breeding population size, and overall genetic diversity. Determine whether eagles produced outside the MSPA immigrate into the MSPA to establish breeding territories and evaluate genetic relationships to other eagle populations in the western United States. | in progress | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California , Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California |
| RES-2 | Submit project metadata, datasets, and Golden Eagle Genetics Study report to the MSP Web Portal. | in progress | Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California , Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California |
| Criteria | Deadline year |
|---|---|
| Golden Eagle Genetic Study with Report Completed by 2020 | 2021 |
| Threat Name | Threat Code |
|---|---|
| Loss of connectivity | LOSCON |
| Urban development | URBDEV |
| File name | Lead Author | Year | Type |
|---|---|---|---|
| A Clarification on the Effects of Urbanization on Golden Eagle (Aquila chrysaetos) Habitat Selection | Tracey, Jeff; Madden, Melanie; Bloom, Peter; Fisher, Robert N. | 2020 | report |
| Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California, February 2016-February 2017 | Bloom, Peter; Fisher, Robert N.; Katzner, Todd; Madden, Melanie; Sebes, Jeremy; Tracey, Jeff | 2017 | report |
| Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California, February 2017-December 2019 | Tracey, Jeff; Madden, Melanie; Molden, James; Sebes, Jeremy; Bloom, Peter; Fisher, Robert N. | 2020 | report |
| Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California, November 2014-February 2016 | Bloom, Peter; Fisher, Robert N.; Katzner, Todd; Madden, Melanie; Sebes, Jeremy; Tracey, Jeff | 2016 | report |
| Golden Eagle Habitat Selection as a Function of Land Use and Terrain, San Diego County, California | Tracey, Jeff; Madden, Melanie; Bloom, Peter; Katzner, Todd; Fisher, Robert N. | 2018 | report |
| Topographic drivers of flight altitude over large spatial and temporal scales | Bloom, Peter; Fisher, Robert N.; Tracey, Jeff; Katzner, Todd; Duerr, Adam; Miller, Tricia; Dunn, Leah; Bell, Douglas | 2019 | journal article |