Photo Credit: Jeff Tracey, USGS
| Historically present | |
| Currently present | |
| Currently not detected |
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 | |
| 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 | 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 | |
| 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 | 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 | 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 | 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 |
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 | 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 | 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 |
Management units: 3, 4, 5, 6, 8, 9, 10, 11
In 2021, use the results and recommendations from the Golden Eagle Nesting, Foraging, and Habitat Use Study and the Golden Eagle Genetics Study to develop a comprehensive Golden Eagle Management Plan for managing golden eagle territories with nesting, roosting, and foraging habitat on Conserved Lands within the MSPA (see occurrence table). The plan should include recommendations for managing important foraging habitat to minimize human disturbance to foraging eagles and to improve habitat quality to enhance prey availability, especially during drought periods. The plan should also include specifications to control human disturbance that could discourage nesting, cause nest abandonment, or adversely affect the survival of nestlings, and for managing unstable nest ledges or tree nest sites that are critical to maintaining a breeding pair in territories with limited nesting sites.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| PRP-1 | Prepare a five year plan for maintaining and enhancing golden eagle foraging habitat in grasslands and suitable areas in open coastal sage scrub and chaparral, and for reducing human impacts to foraging eagles. Use the Golden Eagle Nesting, Foraging, and Habitat Use Study and modeling results to identify important foraging areas for golden eagles on Conserved Lands in the MSPA. Specify management to reduce human disturbance in important foraging habitat and to manage invasive annual grasses to promote abundant prey, such as California ground squirrels and black-tailed jackrabbit. Include a mechanism for updating the management plan with monitoring results and specific management recommendations from the Comprehensive Golden Eagle Monitoring Plan. | waiting for precedent action | |
| PRP-2 | Prioritize for management, those nest ledges and trees that are in territories where alternative nest sites are limited. Prepare a nest restoration plan for each prioritized unstable nest ledge or vulnerable nest tree in consultation with a qualified golden eagle biologist. | waiting for precedent action | |
| PRP-3 | Establish procedures for managing human activities within the nest site protective zone, including rerouting trails, closing trails during the breeding season, educational outreach, and enforcement. | waiting for precedent action | |
| PRP-4 | Submit project metadata and Comprehensive Golden Eagle Management Plan to the MSP Web Portal. | waiting for precedent action |
| Criteria | Deadline year |
|---|---|
| Comprehensive Golden Eagle Management Plan Completed by 2022 | 2021 |
| Threat Name | Threat Code |
|---|---|
| Altered fire regime | ALTFIR |
| Human uses of the Preserves | HUMUSE |
| Invasive animals | INVANI |
| Invasive plants | INVPLA |
| Pesticides | |
| Urban development | URBDEV |
Management units: 3, 4, 5, 6, 8, 9, 10, 11
In 2021, use the results and recommendations from the Golden Eagle Nesting, Foraging, and Habitat Use Study and the Golden Eagle Genetics Study to develop a comprehensive Golden Eagle Monitoring Plan for monitoring golden eagle status and assessing nesting, roosting, and foraging habitat on Conserved Lands within the MSPA (see occurrence table). The plan should include standardized monitoring protocols to track the status of eagles at nesting territories, to monitor use of important foraging areas, and to collect habitat and threats covariate data to inform needed management actions.
| Action | Statement | Action status | Projects |
|---|---|---|---|
| PRP-1 | Complete a plan to monitor the status and habitat use of eagles over the long term within the MSPA that is based upon the occupancy monitoring study in the Golden Eagle Nesting, Foraging and Habitat Use Study. The plan should include detailed monitoring objectives, statistically valid sampling design, sampling locations, monitoring timeline, and standardized monitoring protocols to record eagles and important habitat and threat attributes. | waiting for precedent action | |
| PRP-2 | Develop a plan to rapidly assess the condition of important golden eagle foraging habitat on Conserved Lands across the MSPA using a standardized protocol, statistically valid sampling design, and designated sampling locations. The protocol should describe monitoring methods to collect specific habitat and threat covariates associated with habitat quality, as identified by the Golden Eagle Nesting, Foraging, and Habitat Use Study. The results of this monitoring will be used to periodically prioritize sites and develop specific recommendations for managing foraging habitat to minimize human disturbance and enhance habitat quality to support abundant eagle prey. | waiting for precedent action | |
| PRP-3 | A golden eagle expert should prepare a protocol, standardized data sheets, and provide periodic training to land managers in how to safely conduct annual nest inspections and determine management needs with minimal disturbance to eagles. The protocol should assess nest sites during the non-breeding season to identify nest ledges that are unstable and nest trees that are vulnerable to loss from threats such as wildfire, pests, and fungal pathogens. | waiting for precedent action | |
| PRP-4 | Submit project metadata, sampling design, sampling locations, protocols and Comprehensive Golden Eagle Monitoring Plan to the MSP Web Portal. | waiting for precedent action |
| Criteria | Deadline year |
|---|---|
| Comprehensive Golden Eagle Monitoring Plan Completed by 2022 | 2021 |
| Threat Name | Threat Code |
|---|---|
| Altered fire regime | ALTFIR |
| Human uses of the Preserves | HUMUSE |
| Invasive animals | INVANI |
| Invasive plants | INVPLA |
| Urban development | URBDEV |
|
Five Year Site Occupancy, Nesting Success, Movement Behavior, and Genetic Structure of Golden Eagles in Western San Diego County, California
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 .
|
|
Biotelemetry Data for Golden Eagles (Aquila chrysaetos) Captured in Coastal Southern California
Because of a lack of clarity about the status of golden eagles (Aquila chrysaetos) in coastal southern California, the 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 in coastal southern California, began in September 2014. During trapping efforts from September 29, 2014, to February 23, 2017, 37 golden eagles were captured. During trapping efforts from February 24, 2017, to December 2, 2019, an additional 7 golden eagles (4 females and 3 males) were captured, and one previously captured female was recaptured. Biotelemetry data for 27 of the 44 golden eagles that were transmitting data from February 24, 2017, to December 2, 2019 are presented. These eagles ranged as far north as British Columbia, Canada, and as far south as Ciudad Insurgentes, Baja California, Mexico.
|
|
Golden Eagle (Aquila chrysaetos) Monitoring and Management Plan
Golden eagles (Aquila chrysaetos) face many threats in southern California. To reduce these threats and successfully conserve this species in western San Diego County, MSP Roadmap 2021-2026 objectives include the development and implementation of a Management Strategic Plan for Golden Eagles in San Diego County and a Monitoring Strategic Plan for Golden Eagles in San Diego County. These plans include general sections with background information and rationale for prioritizing and developing monitoring and management recommendations. Previously, the U.S. Geological Survey (USGS) in collaboration with local, State, and other Federal agencies has conducted a multi-year research study of golden eagles to address questions regarding habitat use, movement behavior, nest occupancy, genetic population structure, and human impacts on eagles. From 2016-17, occupancy analyses were conducted and it was concluded that estimates of occupancy were greatest at sample sites with more rugged terrain conditions, lower human development, and lower amounts of scrubland vegetation cover (Weins et al. 2022). Tracking data from the last 10 years in the Western Unites States have shown eagles exhibit long-distance, nonroutine movements that were responsive to the updraft potential of the spatial and temporal landscape they encountered (Poessel et al. 2022). For the development of both Plans, chapters will be shaped based on the latest scientific information regarding occupancy, natal nesting success, juvenile dispersal, movement and biotelemetry, home range estimation, habitat use, and prey availability. Site-based threats assessment will be used to determine the best management practices. These plans are developed with input and guidance provided by the San Diego Golden Eagle working group, which includes include landowners and managers, scientists, species experts, and representatives from non-profit organizations, government, and wildlife agencies. Occurrence-specific management recommendations will be based on working group input and multiple years of data on Golden Eagle population status, habitat associations, and threats. These are living documents as the plans will be updated when new information becomes available or management actions are completed, and new recommendations are needed.
|
|
Proctor Valley Off Highway Vehicle (OHV) Barrier
Installation of the original Proctor Valley off-road barrier segments began in the southwest section of the valley in 2009 on City of San Diego, Public Utilities property and was partially funded by a Land Management Grant (#5001137). Subsequent project proposals submitted to SANDAG EMP, as well as other funding sources, resulted in additional OHV barrier sections installed on CDFW property (2010-2011; #5001327), followed in 2014, via a submission by Chaparral Lands Conservancy (and partners) for a project intended to complete the barrier along the remaining open space stretches of Proctor Valley Road (LMG #5001971). This last section included privately owned lands and CDFW's RJER Proctor Valley East unit. The section of barrier fence included in this project was originally planned for installation in 2014, as part of the EMP funded Proctor Valley Vehicle Barriers Project (Chaparral Lands Conservancy). However, that project ran out of funds following unexpected steep increases in the price of steel.
Implementation of the CDFW project (#5004941) is consistent with the implementation of the Fire and Wildlife Action Plan (FWA) assigned to golden eagle, Quino checkerspot butterfly and Hermes copper butterfly via the limitation of access to OHV activities, thus reducing wildfire risk (and preventing other impacts) to their habitats. This project will also maintain large (>300 acres) open areas within golden eagle territories to meet foraging habitat conditions preferred by eagles. This project was intended to reduce/prevent wildfires and other impacts from unauthorized activities on conserved lands in Proctor Valley. There is an urgent need to control access and prevent impacts before such pressures lead to increased unauthorized access. With the installation of the new OHV barrier section, CDFW staff can focus limited resources on management actions necessary to prevent unauthorized vehicle intrusion from adjacent private lands, now that direct access from Proctor Valley Road has been eliminated.
|
|
Ramona Grassland Raptor Monitoring
A 3-year raptor study was initiated by the County of San Diego Department of Parks and Recreation to collect baseline information on eagle and other raptor activity at the Ramona Grasslands Preserve (preserve). The purpose of this study is to conduct an eagle/raptor foraging study for the Preserve and golden eagle nest monitoring in Bandy Canyon. Baseline information will provide a better understanding of species abundance and distribution within the Preserve, and be useful in informing management decisions (e.g., trail feasibility and alignments, seasonal closures) and will provide a reference point for any future studies or assessments pertaining to public use.
|
|
Regional Grazing Monitoring Plan
This project evaluates using grazing as a management tool for degraded grasslands and coastal sage scrub habitat. Pilot projects will be conducted to look at the efficacy of grazing as management tool and necessary monitoring methods. The project was designed to answer four primary questions (and their associated objectives): 1) How effective is grazing at reducing fire risk? 2) Can grazing effectively enhance disturbed native grassland and forb habitats 3) Can grazing enhance disturbed native coastal sage scrub habitat? 4) Can grazing reduce nonnative grass and forb cover in disturbed coastal sage scrub to increase native shrub cover and bare ground and improve habitat for MSP species such as Quino checkerspot butterfly (Euphydryas editha quino), California gnatcatcher (Polioptila californica), and black-tailed jackrabbit (Lepus californicus)? Initial study sites were established at Rancho Jamul Ecological Reserve and Hollenbeck Canyon Wildlife Area. This is a SANDAG-funded project.
|
| 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 |
| 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, 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 (Aquila chrysaetos) Habitat Selection as a Function of Land Use and Terrain, San Diego County, California | Tracey, Jeff; Madden, Melanie; Bloom, Peter H.; Katzner, Todd; Fisher, Robert N. | 2018 | 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 |
| Golden Eagle Occupancy Surveys and Monitoring Strategy in Coastal Southern California, United States | Wiens, David ; Bloom, Peter; Madden, Melanie; Kolar, Patrick, S.; Tracey, Jeff; Fisher, Robert N. | 2022 | journal article |
| Interpreting long-distance movements of non-migratory golden eagles: Prospecting and nomadism? | Poessel, Sharon, A.; Woodbridge, Brian; Smith, Brian, W.; Murphy, Robert; Bedrosian, Bryan, E.; Bell, Douglas; Bittner, David; Bloom, Peter; Crandall, Ross, H.; Domenech, Robert; Fisher, Robert N.; Haggarty, Patricia, K.; Slater, Steven, J.; Tracey, Jeff; Watson, James, W.; Katzner, Todd | 2022 | journal article |
| Linking behavioral states to landscape features for improved conservation management | Sur, Maitreyi; Woodbridge, Brian; Esque, Todd C.; Belthoff, Jim R.; Bloom, Peter H.; Fisher, Robert N.; Longshore, Kathleen; Nussear, Kenneth E. ; Tracey, Jeff; Braham, Melissa A.; Katzner, Todd | 2021 | journal article |
| Prioritizing conserved areas threatened by wildfire and fragmentation for monitoring and management | Diffendorfer, Jay; Fisher, Robert N.; Franklin, Janet; Hathaway, Stacie; MacKenzie, Jason; Oberbauer, Thomas; Preston, Kris; Rochester, Carlton; Syphard, Alexandra; Tracey, Jeff; Tremor, Scott; Vandergast, Amy; Winchell, Clark | 2018 | journal article |
| Recording - December 2022 SDMMP Annual End-of-Year Management and Monitoring Coordination Meeting | Vickers, Winston; Smith, Trish; Smith, Kim; Fisher, Robert N.; Price, Jennifer; McCutcheon, Sarah; Pesce, Courtney; Preston, Kris; Perkins, Emily; Brown, Chris; Bernabe, Annabelle; Roesler, Elizabeth | 2022 | recording |
| Recording - January 2024 SDMMP Management and Monitoring Coordination Meeting | Fisher, Robert N. | 2024 | recording |
| Relevance of individual and environmental drivers of movement of Golden Eagles | Sur, Maitreyi; Duerr, Adam; Fisher, Robert N.; Tracey, Jeff; Bloom, Peter H.; Miller, Tricia; Katzner, Todd | 2020 | journal article |
| Report on the Status of the Golden Eagle in the San Diego MSCP 2004-2010 | Bittner, David; Meador, Chris; Rivard, Renee; Scholtfeldt, Brittany | 2010 | report |
| Satellite Telemetry Takes Bird Banding to New Heights | Bittner, Leigh | 2010 | other |
| Topographic drivers of flight altitude over large spatial and temporal scales | Duerr, Adam E.; Miller, Tricia; Dunn, Leah; Bell, Douglas A.; Bloom, Peter H.; Fisher, Robert N.; Tracey, Jeff; Katzner, Todd | 2019 | journal article |
| Topographic drivers of flight altitude over large spatial and temporal scales | Duerr, Adam; Miller, Tricia; Dunn, Leah; Bell, Douglas A.; Bloom, Peter; Fisher, Robert N.; Tracey, Jeff; Katzner, Todd | 2019 | journal article |
| 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 |
Holarctic distribution (Eurasia, N. Africa, and N. America); in N. America breeds locally from northern Alaska eastward to Labrador southward to N. Baja Calif., N. Mexico, and Maine; winters from S. Alaska and S. Canada southward through the breeding range [1].
BEPA/ FP
Uses a variety of habitats; nests in cliffs or trees, forages over plains, grasslands, or low and open shrublands including chaparral and coastal sage scrub [2].
Five or 6 recognized subspecies differentiated by geographic distribution, size and coloration; only one subspecies, Aquila chrysaetos canadensis is found in N. America [3].
Year-long, diurnal activity [4]. Spends most of the day perched (78 to 85%) and the rest of the day in flight [5]. Breeds from late January through August, with peak in March through July [9].
About 80% of nests built in SD Co. have been on cliff ledges and 20% in trees, usually on steep slopes [2]. Pairs may build more than one nest and attend them prior to laying eggs; large platform nests are built of sticks, twigs, and greenery; clutch size is 1-3 eggs; eggs are laid in early February to mid-May; incubation lasts 43-45 days, and the nestling period usually is 65-70 days [2, 9, 10].
Eats mostly lagomorphs and rodents; it also takes other medium to large mammals, birds, reptiles, and some carrion [6,7] Forages over large areas of grassland and open chaparral or coastal sage scrub [8].
Home range sizes vary with season and quality of habitat; during the breeding season, in the western U.S. home ranges vary from 20 to 33 square km; some eagles are sedentary while others are migratory [3].
Human disturbance of nest areas leading to desertion of the nest in early incubation, urbanization, poaching, and electrocutionfrom high tension wires, direct mortality from wind turbines [11,12].
Special considerations: excerpted from the Western Riverside Co. MSHCP (see Riverside County 2003 and citations within) - The golden eagle is sensitive to human disturbance and to land use changes that disrupt natural food supplies and nesting sites. Human activities are known to impact raptors by means such as: physically harming or killing eggs, young or adults; by altering habitat; and by disrupting normal behavior (Richardson and Miller 1997). Due to the broad range of direct and indirect human-associated impacts, establishment of buffer zones created around a nest location provide protection and work best if they include both a spatial and temporal restriction (Richardson and Miller 1997). A specificdetermination of the buffer distance required to prevent disturbance of nest sites has not been determined empirically for the golden eagle (Dave Bittner 1998 pers. comm.; Newton 1979). In one study, home ranges adjoining developed sections of an area were shown to be abandoned more often than interior areas; however, there is no distinct relationship between the proximity of nests to development and their probability or year of abandonment (Scott 1985). The loss of a nesting area could not be attributed to the loss of a specified amount of any vegetation type within 2.5 kilometers of nests (Scott 1985). In addition, the loss of suitable foraging habitat around active nests was equal to, or in some cases greater than, the loss around abandoned areas. In a study of golden eagles in San Diego County, the count of residences was the only variable measured that showed a significant correlation to the number of abandoned areas. A significantly larger number of active areas had no dwelling units within a radius of 1.6 kilometers while a significantly larger number of abandoned areas contained 50 or more dwelling units within the same radius (Scott 1985). In agreement with this species-specific study, an analysis by various biologists concluded that for the golden eagle, a spatial buffer of 200 meters to 1.6 kilometers was recommended (Richardson and Miller 1997). Temporal buffers provide additional support to the spatial buffer and have been recommended to encompass all nesting activities and extend at least from the arrival of the adult birds in the nesting areas through the first few weeks of nestling development (Richardson and Miller 1997).
[1] Brown, L., and D. Amadon. 1968. Eagles, hawks and falcons of the world. 2 Vols. Country Life Books, London. 945pp.
[2] Scott, T. A. 1985. Human impacts on the golden eagle population of San Diego County from 1928 to 1981. Ph.D. Thesis, San Diego State University 98 pp.
[3] Kochert, M., K. Steenhof, C. McIntyre, E. Craig. 2002. Golden Eagle (Aquila chrysaetos). PP. 1-44. In: A. Poole, F. Gill (Eds.), The Birds of North America, Vol. 684. Philadelphia: The Birds of North America.
[4] Zeiner, D. C., W., F. Laudenslayer, Jr., K. E. Mayer, M. White. Editors. 1990. California's Wildlife. Volume 2. Birds. State of California, Department of Fish and Game. Sacramento, California. 731 pp.
[5] Collopy, M. W., and T. C. Edwards, Jr. 1989. Territory size, activity budget, and role of undulating flight in nesting golden eagles. J. Field Ornithology 60: 43-51.
[6] Johnsgard, P.A. 1990. Hawks, eagles, and falcons of North America. Smithsonian Institution Press, Washington, D.C.
[7] Olendorff, R. R. 1976. The food habits of North American golden eagles. Amer. Midl. Nat. 95:231-3-236.
[8] Marzluff, J. M., S. T. Knick, M. S. Vekasy, L. S. Shcueck, and T. J. Zarriello. 1997. Spatial use and habitat selection of golden eagles in southwestern Idaho. Auk 114: 673-687.
[9] McGahan, Jerry. 1968. Ecology of the Golden Eagle. The Auk 85: 1-12.
[10] Beebe, F. L. 1974. Field studies of the Falconiformes of British Columbia. Brit. Col. Prov. Mus. Occas. Pap. No. 17. 163pp.
[11] Remsen, J. V., Jr. 1978. Bird species of special concern in California. Calif. Dep. Fish and Game, Sacramento. Wildl. Manage. Admin. Rep. No. 78-1. 54 pp.
[12] Thelander, C. G. 1974. Nesting territory utilization by golden eagles (Aquila chrysaetos) in California during 1974. Calif. Dept. Fish and Game, Sacramento. Wildl. Manage. Branch Admin. Rep. 74-7. 19pp.