Reintroducing endangered raptors: A case study of supplementary feeding and removal of nestlings from wild populations

Ferrer, Miguel; Morandini, Virginia; Báguena, Gerardo; Newton, Ian

doi:10.1111/1365-2664.13014

Cited by 33 publications

(32 citation statements)

References 30 publications

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“…Considering the age of first breeding as a fixed value not only introduces error to simulations of reintroduced populations, but also in all the scenarios where, for various reasons, we have fluctuations in the availability of vacant territories. This is the case for simulations of the effect of repeated extractions from a donor population (Ferrer et al, ; Morandini & Ferrer, ). For example, in recently published papers (Margalida et al, ), simulations of the effect of repeated extractions in a Bearded Vulture ( Gypaetus barbatus ) population for reintroduction programs were conducted.…”

Section: Discussionmentioning

confidence: 99%

“…The present biodiversity crisis has led to an increasing number of reintroduction programs (Seddon, Armstrong, & Maloney, ), and it seems that this conservation method will be increasingly used in the future, especially in the face of climate change (Ferrer, Morandini, Baguena, & Newton, ; Morandini & Ferrer, ). It is well known that density dependence affects several relevant parameters in population dynamics (Ferrer & Donazar, ), including mortality which increases when density increases (e.g., through increasing rates of territorial disputes and fighting among breeders or increasing juvenile starvation), productivity which increases when density decreases, and age of first breeding which decreases when density decreases (Ferrer & Bisson, ; Ferrer et al, ; Morandini, Benito, Newton, & Ferrer, ; Newton, ).…”

Section: Introductionmentioning

confidence: 99%

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The role of age of first breeding in modeling raptor reintroductions

Morandini

Dietz

Newton

et al. 2019

Ecology and Evolution

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The present biodiversity crisis has led to an increasing number of reintroduction programs, and this conservation method is likely to be increasingly used in the future, especially in the face of climate change. Many fundamental questions in population ecology are focused on the mechanisms through which populations escape extinction. Population viability analysis (PVA) is the most common procedure for analyzing extinction risk. In the use of PVA to model the trajectories of reintroduced populations, demographic values are sometimes taken from other existing wild populations or even from individuals in captivity. Density dependence in productivity is usually considered in viability models, but density‐dependent variation in age of first breeding is usually ignored. Nevertheless, age of first breeding has a buffering effect on population fluctuations and in consequence on population persistence. We simulated the viability of Spanish Imperial Eagle ( Aquila adalberti ) and Osprey ( Pandion haliaetus ) populations using data from established and reintroduced populations in southern Spain. Our results show that reduction in the age of first breeding is critical in the success of reintroductions of such long‐lived birds. Additionally, increases in productivity allow populations to growth at maximum rate. However, without considering variation in age of breeding, and the associated increasing overall productivity, reintroduced populations seem nonviable. To ignore density dependence in age of breeding in PVA means that we are seriously limiting the potential of the model population to respond to fluctuations in density, thereby reducing its resilience and viability. Variation in age of first breeding is an important factor that must be considered and included in any simulation model involving long‐lived birds with deferred maturity.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The role of age of first breeding in modeling raptor reintroductions

Morandini

Dietz

Newton

et al. 2019

Ecology and Evolution

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“…One key strength of our model, relative to studies elsewhere (Dwyer et al, 2014(Dwyer et al, , 2016Guil et al, 2011;Mañosa, 2001;Pérez-García et al, 2017), is that the electrocution risk assessment was ap- Spanish imperial eagle has been considered one of the most endangered raptors in the world (Ferrer, Morandini, Baguena, Newton, & Thompson, 2017), and its electrocution rate has been reported to be the main known cause of death for the species, accounting for 60% of mortality cases (López-López et al, 2011). Our data show that electrocution on poles continues to kill the Spanish imperial eagle.…”

Section: Predictive Electrocution Risk Modellingmentioning

confidence: 84%

“…On the other hand, raptor electrocutions on power lines can jeopardise populations of threatened species and even cause their extinction (see Section ). For example, the Spanish imperial eagle has been considered one of the most endangered raptors in the world (Ferrer, Morandini, Baguena, Newton, & Thompson, ), and its electrocution rate has been reported to be the main known cause of death for the species, accounting for 60% of mortality cases (López‐López et al., ). Our data show that electrocution on poles continues to kill the Spanish imperial eagle.…”

Section: Discussionmentioning

confidence: 99%

Where to start? Development of a spatial tool to prioritise retrofitting of power line poles that are dangerous to raptors

Hernández‐Lambraño

Sánchez‐Agudo

Carbonell

2018

Journal of Applied Ecology

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Avian electrocution on power lines is a major conservation issue on a global scale. Electrocution risk models have recently been proposed as an effective alternative to prioritising high‐risk pole retrofitting activities at a large scale. However, existing models ignore the specific features of the power poles (hereafter, poles) supporting the power distribution lines and make the tenuous assumption that pole density and power line length are key factors to assessing the electrocution risk at a large scale. This assumption may be violated in areas with high variations in pole configuration. In this study, we used data on raptors electrocuted on poles to develop a predictive model of raptor electrocution risk throughout an extensive geographical area in north‐western Spain, using boosted regression trees. With the best‐fitting model, we predicted the hazard of a set of 188,741 poles and validated the model predictions with new data collected from the study area. Our model highlights the relevance of combining both habitat and technical features to identify the most dangerous poles for raptors on a large geographical scale. A 9.86% of the total poles evaluated were characterised as high risk for raptors. The model showed good performance in external validation. The new electrocution events were registered at poles with high‐risk values. Synthesis and applications. In this study, we improved the accuracy of the predictive models of raptor electrocution risk for large geographical areas. By incorporating the technical characteristics of the power poles into the models, we achieved a high level of prediction at the power pole level, which is the ultimate correction unit. This will allow electric companies and wildlife managers to specify retrofitting activities of high‐risk power poles for raptors in large geographical areas, thus maximising the effect of investment in the correction of dangerous power poles and conservation of the raptor populations.

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“…supplemental feeding of offspring increases reproductive output; Ferrer et al . ). As such, our observations have substantial implications for our understanding of the causes and consequences of the energetic limitations for monogamous territorial species in general.…”

Section: Discussionmentioning

confidence: 97%

Relevance of individual and environmental drivers of movement of Golden Eagles

Sur

Duerr²,

Bell³

et al. 2019

Ibis

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An animal's movement is expected to be governed by an interplay between goals determined by its internal state and energetic costs associated with navigating through the external environment. Understanding this ecological process is challenging when an animal moves in two dimensions and even more difficult for birds that move in a third dimension. To understand the dynamic interaction between the internal state of an animal and the variable external environment, we evaluated hypotheses explaining association of different covariates of movement and the trade‐offs birds face as they make behavioural decisions in a fluctuating landscape. We used ~870 000 GPS telemetry data points collected from 68 Golden Eagles Aquila chrysaetos to test demographic, diel, topographic and meteorological hypotheses to determine (1) the probability that these birds would be in motion and (2), once in motion, their flight speed. A complex and sometimes interacting set of potential internal and external factors determined movement behaviour. There was good evidence that reproductive state, manifested as age, sex and seasonal effects, had a significant influence on the probability of being in motion and, to a lesser extent, on speed of motion. Likewise, movement responses to the external environment were often unexpectedly strong. These responses, to northness of slope, strength of orographic updraft and intensity of solar radiation, were regionally and temporally variable. In contrast to previous work showing the role of a single environmental factor in determining movement decisions, our analyses support the hypothesis that multiple factors simultaneously interact to influence animal movement. In particular they highlighted how movement is influenced by the interaction between the individual's internal reproductive state and the external environment, and that, of the environmental factors, topographic influences are often more relevant than meteorological influences in determining patterns of flight behaviour. Further disentangling of how these internal and externals states jointly affect movement will provide additional insights into the energetic costs of movement and benefits associated with achieving process‐driven goals.

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Reintroducing endangered raptors: A case study of supplementary feeding and removal of nestlings from wild populations

Cited by 33 publications

References 30 publications

The role of age of first breeding in modeling raptor reintroductions

The role of age of first breeding in modeling raptor reintroductions

Where to start? Development of a spatial tool to prioritise retrofitting of power line poles that are dangerous to raptors

Relevance of individual and environmental drivers of movement of Golden Eagles

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