Responses of dispersing GPS‐tagged Golden Eagles (<i>Aquila chrysaetos</i>) to multiple wind farms across Scotland

Fielding, Alan H.; Anderson, David J.; Benn, Stuart; Dennis, R.A.; Geary, Matthew; Weston, Ewan; Whitfield, D. Philip

doi:10.1111/ibi.12996

Cited by 10 publications

(33 citation statements)

References 105 publications

(301 reference statements)

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“…Telemetry data obtained up to mid-November 2020 were used in analyses. Tags were deployed at nests across several regions of Scotland (Fielding et al, 2012;Whitfield and Fielding, 2017). Nestlings were sexed on the basis of biometrics, supplemented by molecular techniques from an opportunistic sample, which confirmed biometric assignations (Weston et al, 2018).…”

Section: Satellite Taggingmentioning

confidence: 99%

Age of First Territory Settlement of Golden Eagles Aquila chrysaetos in a Variable Competitive Landscape

Whitfield¹,

Fielding²,

Anderson³

et al. 2022

Front. Ecol. Evol.

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With life-history traits involving high survival, low reproductive output, years of natal dispersal and deferred maturity, the population ecology and behaviour of large raptors which occur at low densities can be difficult to study. The age at which large raptors first settle on a prospective breeding territory receives relatively little attention, but is a key metric in population modelling including, for example, projections of reintroduction projects. It can also be a barometer of the “health” of populations and the availability of breeding opportunities. The advancement of GPS-telemetry has proved invaluable in gaining insights into several aspects of large raptor ecology and behaviour. Age of first territory settlement (AFTS) is one such aspect. AFTS is important in modelling population trajectories and considering individuals’ lifetime reproductive success. We used an algorithm based on GPS-records from dispersing Golden Eagles tagged as nestlings in Scotland to estimate AFTS. While the lifespan of GPS-tags can bias against settlement dates of older birds, they can also potentially reveal settlement ages difficult or impossible to discern from other methods. We found a range of ages for AFTS, including those in their second calendar year; much younger than previously documented by other methods. Ground-truthing – when possible and if inevitably slightly delayed – confirmed territory occupation on field-based survey criteria. We found that eagles settled younger in vacant territories and when older in occupied existing territories. Birds’ sex had no effect on AFTS. Birds which dispersed earlier from their natal territory (indicative of “quality” from some previous research) had no association with AFTS. Our results indicate that within technological temporal limits GPS-data can provide for accurate and precise estimations of AFTS including early settlement not consistently or precisely recorded by other methods. Within our study’s variable competitive landscape we found that AFTS was associated with the availability of territorial opportunities but not with the timing of dispersal. These findings have consequences for studying and understanding large raptor population dynamics.

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Section: Satellite Taggingmentioning

confidence: 99%

Age of First Territory Settlement of Golden Eagles Aquila chrysaetos in a Variable Competitive Landscape

Whitfield¹,

Fielding²,

Anderson³

et al. 2022

Front. Ecol. Evol.

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“…The existing methods for researching soaring bird migration include mainly different kinds of telemetry, primarily using GPS tags (Fielding et al, 2022; Kumar et al, 2020; Vignali et al, 2022). These methods allow tracking of up to several dozen individuals from a certain population due to financial and logistical challenges.…”

Section: Discussionmentioning

confidence: 99%

“…The existing methods for researching soaring bird migration include mainly different kinds of telemetry, primarily using GPS tags (Fielding et al, 2022;Kumar et al, 2020;Vignali et al, 2022). These Importantly, where wide-spread radar networks are available (e.g.…”

Section: F I G U R Ementioning

confidence: 99%

Automatic detection of migrating soaring bird flocks using weather radars by deep learning

et al. 2023

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The use of weather radars to detect and distinguish between different biological patterns greatly improves our understanding of aeroecology and its consequences for our lives. Importantly, it allows us to quantify passerine bird migration at different scales. Yet, no algorithm to detect soaring bird flocks in weather radar is available, precluding our ability to study this type of migration over large spatial scales. We developed the first automatic algorithm for detecting the migration of flocks of soaring birds, an important bio‐flow phenomenon involving many millions of birds that travel across large spatial extents, with implications for risk of bird‐aircraft collisions. The algorithm was developed with a deep learning network for semantic segmentation using U‐Net architecture. We tested several models with different weather radar products and with image sequences for flock movement identification. The best model includes the radial velocity product and a sequence of two previous images. It identifies 93% of soaring bird flocks that were tagged by a human on the radar image, with a false discovery of less than 20%. Large birds such as those detected by the algorithm pose a serious risk for flight safety of civilian and military transportation and therefore the application of this algorithm can substantially reduce bird‐strikes, leading to reduced financial losses and threats to human lives. In addition, it can help overcome one of the main challenges in the study of bird migration by automatically and continuously detecting flocks of large birds over wide spatial scales without the need to equip the birds with tracking devices, unravelling the abundance, timing, spatial flyways, seasonal trends and influences of environmental conditions on the migration of bird flocks.

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“…2017, Fielding et al . 2022), which are also used by non‐territorial birds (Whitfield et al . 2008, Whitfield & Fielding 2017, Fielding et al .…”

Section: Methodsmentioning

confidence: 99%

“…2006) appears largely to create potential functional habitat loss, rather than mortality through collision with turbine blades (Fielding et al . 2021, 2022).…”

Section: Methodsmentioning

confidence: 99%

Sex difference in natal dispersal distances of Golden Eagles Aquila chrysaetos in Scotland

Whitfield

Fielding

Anderson³

et al. 2023

Ibis

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Natal dispersal distance (NDD) is critical in understanding and defining populations and their conservation. It is defined as the linear distance between the natal location and first reproductive (‘effective NDD’) or potential reproductive (‘gross NDD’) location. It is a measure of gene flow and the functional connectivity across generations between individuals breeding in the same or different geographies. NDD is difficult to record in large raptors. GPS‐satellite telemetry has facilitated its recording. Previous Scottish studies showed that gross and effective NDD were apparently equivalent, and an algorithm based on telemetric data could identify the territory settlement timing and location of birds originally tagged as nestlings. We analysed natal dispersal data from 39 Golden Eagles GPS‐tagged in Scotland to estimate NDD. Raw median estimates were 29.8 km for males (n = 22) and 58.6 km for females (n = 17), 38.1 km averaged across sexes. Males had significantly shorter NDD, as theoretically predicted. Our NDD estimates were shorter but not grossly dissimilar to those from the USA, where sex differences in NDD had not been confirmed. Respective sample sizes may underly the latter contrast in confirmation. We also showed that in the absence of data from sexed birds, NDD estimates can be different. Natal dispersal duration was not related to NDD, suggesting that time to prospect a territory opportunity was not associated with the selected territory's distance from the natal site. The previous status of the subsequent settled territory (occupied or vacant) was also not related to NDD. We conclude that sex differences in NDD are important in application to population demography and conservation. Although we found no support for two other potential drivers of NDD (natal dispersal duration and previous territory status), identifying additional influences on NDD is in its infancy in large raptors and deserves more study.

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Responses of dispersing GPS‐tagged Golden Eagles (Aquila chrysaetos) to multiple wind farms across Scotland

Cited by 10 publications

References 105 publications

Age of First Territory Settlement of Golden Eagles Aquila chrysaetos in a Variable Competitive Landscape

Age of First Territory Settlement of Golden Eagles Aquila chrysaetos in a Variable Competitive Landscape

Automatic detection of migrating soaring bird flocks using weather radars by deep learning

Sex difference in natal dispersal distances of Golden Eagles Aquila chrysaetos in Scotland

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