Golden eagle (Aquila chrysaetos) habitat selection as a function of land use and terrain, San Diego County, California

Tracey, Jeff A.; Madden, Melanie C.; Bloom, Peter H.; Katzner, Todd E.; Fisher, Robert N.

doi:10.3133/ofr20181067

Cited by 3 publications

(6 citation statements)

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“…These findings were in general accordance with predicted habitat associations of golden eagles from previous studies of site occupancy that we used to guide model development (Wiens et al, 2018;Tack et al, 2020). Moreover, our findings echoed those from historical surveys (Dixon, 1937;Scott, 1985) and more recent telemetry studies of individually marked birds (Tracey et al, 2018a(Tracey et al, , 2020 that emphasized the sensitivity of golden eagles to expanding human development. Together, these previous studies and ours highlight the conservation value of remote, non-urbanized landscapes to remaining breeding pairs of golden eagles in coastal southern California.…”

Section: Discussionsupporting

confidence: 90%

“…Based on these previous findings, and the results of a site-occupancy study in westcentral California (Wiens et al, 2015(Wiens et al, , 2018, we predicted that occupancy of golden eagle pairs would be positively associated with open (grassland) landscapes with increasingly rugged terrain conditions, but negatively associated with dense chaparral scrubland. Finally, we predicted that site occupancy of eagles would be lower at sites with relatively more human development (Scott, 1985;Tracey et al, 2018a). We then demonstrate how the monitoring design may be used to estimate and map the spatial distribution of sites most likely to be used by territorial pairs of golden eagles, which should be useful for supporting local conservation priorities or management decisions for this federally protected species.…”

Section: Introductionmentioning

confidence: 84%

“…With increasing urbanization, golden eagles may be increasingly restricted to cliff-side nests in more rugged, inland landscapes of southern California, including deserts to the east (Brown, 2014). Resident birds, non-territorial individuals (i.e., floaters and younger age-classes), and migratory eagles all use the region in winter (Tracey et al, 2018a(Tracey et al, , 2020.…”

Section: Study Area and Eagle Populationmentioning

confidence: 99%

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Golden Eagle Occupancy Surveys and Monitoring Strategy in Coastal Southern California, United States

Wiens

Bloom²,

Madden

et al. 2022

Front. Ecol. Evol.

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Golden eagles (Aquila chrysaetos) are of increasing conservation concern in western North America. Effective conservation measures for this wide-ranging, federally protected raptor species require monitoring frameworks that accommodate strong inference on the status of breeding populations across vast landscapes. We used a broad-scale sampling design to identify relationships between landscape conditions, detection rates, and site occupancy by territorial pairs of golden eagles in coastal southern California, United States. In 2016 and 2017, we surveyed 175 territory-sized sample sites (13.9-km2 randomly selected grid cells) up to four times each year and detected a pair of eagles at least once in 22 (12.6%) sites. The probability of detecting pairs of eagles varied substantially between years and declined with increasing amounts of forest cover at survey sites, which obscured observations of eagles during ground-based surveys. After accounting for variable detection, the mean estimate of expected site occupancy by eagle pairs was 0.156 (SE = 0.081). Site-level estimates of occupancy were greatest (>0.30) at sample sites with more rugged terrain conditions, <20% human development, and lower amounts of scrubland vegetation cover. The proportion of a sample site with open grassland or forest cover was not strongly correlated with occupancy. We estimated that approximately 16% of the 5,338-km2 sampling frame was used by resident pairs of golden eagles, corresponding to a sparsely distributed population of about 60 pairs (95% CI = 19 – 151 pairs). Our study provided baseline data for future surveys of golden eagles along with a widely applicable monitoring framework for identifying spatial conservation priorities in urbanizing landscapes.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 84%

Section: Study Area and Eagle Populationmentioning

confidence: 99%

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Golden Eagle Occupancy Surveys and Monitoring Strategy in Coastal Southern California, United States

Wiens

Bloom²,

Madden

et al. 2022

Front. Ecol. Evol.

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“…Nevertheless, studies of this species' habitat selection, whether for birds on migration, resident territory holders or dispersing young, show a similar common feature of preference for ridges, 'complex topographical features' or other topographical features associated with ridges (e.g. Katzner et al 2012, Singh et al 2016, Miller et al 2017, Tracey et al 2018.…”

Section: Discussionmentioning

confidence: 99%

“…Studies of Golden Eagle habitat use have involved both migratory (e.g. Brodeur et al 1996, Alerstam 2001, McIntyre et al 2008, Duerr et al 2012, Johnston et al 2013, Moss et al 2014, Domenech et al 2015 and non-migratory birds (Marzluff et al 1997, Carrete et al 2000, McLeod et al 2002b, Sergio et al 2006, Tapia et al 2007, Sandgren et al 2014, Watson et al 2014, Braham et al 2015, Poessel et al 2016, Miller et al 2017, Tracey et al 2018. Later studies have benefitted from GPS telemetry (L opez-L opez 2016).…”

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confidence: 99%

A simple topographical model to predict Golden Eagle Aquila chrysaetos space use during dispersal

Fielding¹,

Haworth²,

Anderson

et al. 2019

Ibis

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Many large raptors exploit or rely on anabatic and orographic winds which provide vertical lift, to supplement or provide the energy fuelling flight. Airspace is therefore a critical habitat for such large raptors and its use is subject to the underlying terrestrial topography, because particular topographical features are more likely to provide wind‐energetic lift. Accordingly, ridges and/or ‘rugged topography’ are common preferred features in habitat use by large raptors. Our study aimed to provide a simple model of space use for a large raptor, the Golden Eagle Aquila chrysaetos, based on thousands of GPS telemetry records during juvenile dispersal of 92 birds tagged as nestlings between 2007 and 2016 across upland Scotland. Model development was based on the hypothesis that four topographical variables would be influential: slope, aspect, altitude and distance from ridge. The telemetry dataset was divided into training and two testing components. The first testing set was derived by a temporal split resulting in approximately equal sample size on records and some temporal overlap in individuals’ records with training data. The second testing set involved no individuals from the training set. Aspect was removed early in training model development because it was not influential. The model found that young Golden Eagles preferred, or used according to availability, space above slopes greater than 10°, at an altitude of ≥ 300 m, and within 300 m of a ridge. The test data were highly correlated with those from the training data in the model variables, and performance as regard to expected preferences from the model was improved in both test datasets, indicating the model was robust. Given the apparent universal nature of large raptor dependence on topography, that topography is relatively immutable according to time and use, and that topographical data are readily available, we commend our approach to other habitat preference studies of Golden Eagles and other large raptors elsewhere.

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Projecting the remaining habitat for the western spadefoot (Spea hammondii) in heavily urbanized southern California

Rose

Halstead

Packard³

et al. 2022

Global Ecology and Conservation

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Golden eagle (Aquila chrysaetos) habitat selection as a function of land use and terrain, San Diego County, California

Cited by 3 publications

References 1 publication

Golden Eagle Occupancy Surveys and Monitoring Strategy in Coastal Southern California, United States

Golden Eagle Occupancy Surveys and Monitoring Strategy in Coastal Southern California, United States

A simple topographical model to predict Golden Eagle Aquila chrysaetos space use during dispersal

Projecting the remaining habitat for the western spadefoot (Spea hammondii) in heavily urbanized southern California

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