Guiding local-scale management to improve the conservation of endangered populations: the example of Bonelli’s Eagle<i>Aquila fasciata</i>

Rollan, Àlex; Hernández‐Matías, Antonio; Bosch, Rafel; Tintó, Albert; Puig-Gironès, Roger; Castell, Carles; Real, Joan

doi:10.1017/s0959270920000519

Cited by 4 publications

(2 citation statements)

References 51 publications

(53 reference statements)

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“…He also suggested that the proximity of electric pylons to water reservoirs contributed the most to the mortality by electrocution in the species. Similarly, in Portugal, Bonelli's Eagle was also attracted to power lines [64] and is considered to be amongst the main causes of mortality in the species throughout its breeding range [65,66]. We recommended that the relevant authorities implement the building of raptor-friendly pylons or retrofit them with preventive apparatus to avoid continued avian mortality throughout Israel.…”

Section: Discussionmentioning

confidence: 99%

Sustaining Increasing Wintering Raptor Populations in Central Israel: A 38 Years Perspective

2022

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Censusing wintering raptors has proved useful in detecting changes in populations. Israel is a well-known bottleneck for soaring birds in the autumn and the spring. Despite the many studies on migratory raptors in Israel, none have undertaken the study of the overwintering raptors consistently over extended periods, such as 1985–2022, a period of 38 years. During the study, conducted in central Israel, we recorded 44,120 individuals from 32 species. The most frequently observed species were Black Kite (Milvus migrans; 59.1%), Common Kestrel (Falco tinnunculus; 18.1%), and Steppe Buzzard (Buteo vulpinus; 6.6%). We found an increase in the total number of individuals, where the mean increase compared to the starting year was 851.6 ± 1071.2%, and the average annual growth was 43.7 ± 158.8%, respectively. A similar pattern was found in the number of species during the study period, where the mean annual increase was 17.1 ± 20.5%, and the average annual growth rate of species richness was 2.2 ± 16.2%. However, an evaluation of the mortality from power lines of two listed species suggests that the wintering raptors are not well protected in the study area. The conservation of these raptors and the possible sustainability of their wintering populations into the future, some of which are on the IUCN Red List, are of great importance, and the authorities should try and understand the human demographics and mesohabitat changes that appear to influence the wintering capabilities of the raptor populations.

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Section: Discussionmentioning

confidence: 99%

Sustaining Increasing Wintering Raptor Populations in Central Israel: A 38 Years Perspective

2022

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“…Specifically, at the regional level, the species has gone from being considered a “vulnerable” species to “endangered of extinction” in the Valencian Community 35 . This change in risk category was based on a population viability analysis in which, fundamentally thanks to the combined use of GPS transmitters and long-term field monitoring, it was found that the population trend is compromised in the medium and long term due to a high pre-adult and adult mortality, analogous to that reported in other neighbouring geographic regions 36 – 38 . In particular, since 2000, the Bonelli’s eagle population has suffered a decline of 48.6% in the region, with an observed reduction of the breeding population from 31 territories occupied in 2000 to 18 occupied in 2022 39 , 40 .…”

Section: Introductionmentioning

confidence: 95%

Potential negative effects of the installation of video surveillance cameras in raptors’ nests

López‐López

2022

Sci Rep

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Video surveillance cameras installed on birds’ nests are a cost-effective tool to study many aspects of ecology and behaviour that would otherwise be practically impossible to obtain. However, although most studies report neutral effects of cameras on birds, very few studies analyse in detail the potential negative effects of their use, particularly on raptors. Here, using a long-term database of a population of Bonelli’s eagle (Aquila fasciata) collected from 2000 to 2022, I show how the inappropriate use of video surveillance cameras could result in negative effects on the reproduction of a threatened species through a before-and-after control-impact study design. Pairs under video surveillance showed lower productivity, lower breeding success and unusual delayed laying dates. The installation of cameras close to the laying date, coinciding with the mating phase of individuals, most of them subadult inexperienced birds; in combination to the reiteration of visits to the nests once the cameras were installed to check the system, particularly during the incubation period and early stages of breeding; and the installation of cameras in a particular area subject to constant human disturbance, might explain these results. Potential management actions to mitigate the effect of the installation of video cameras on birds’ behaviour should include the need to plan the intervention dates, testing the systems beforehand under controlled conditions and adequate post-installation monitoring to avoid unnecessary disturbance to animals. Finally, I urge the scientific community to report the potential negative effects observed in their studies, especially if the target species are threatened with extinction.

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A comprehensive analysis of spatial and temporal patterns of anthropogenic adult mortality of Bonelli's eagles in eastern Spain

López‐Peinado,

Urios,

López‐López

2024

J Wildl Manag

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In eastern Spain, Bonelli's eagle (Aquila fasciata) abundance has declined almost 50% in the last 25 years and, consequently, the species is listed as regionally endangered. Therefore, the aim of this study is to report the mortality causes of territorial breeding Bonelli's eagles, including the spatial and temporal patterns, and to assess the effects on population dynamics. From 2015–2023, we tracked 60 Bonelli's eagles via global positioning system‐global system for mobile communications (GPS‐GSM) telemetry; 33 of the eagles died (median survival time = 1,519 days). Survival did not differ in relation to sex, age at capture (subadult vs. adult birds), breeding site (coastland vs. inland territories), or transmitter's model. One‐year probability of survival (95% CI) was 0.716 (0.607–0.845); 2‐year survival was 0.640 (0.524–0.781); and 3‐year survival was 0.581 (0.464–0.729). Anthropogenic mortality (66.7% of cases) prevailed over natural (27.3%) and unknown causes (6.0%). Causes of mortality were intra‐ and interspecific predation (24.2% of cases), electrocution (18.2%), poisoning (15.1%), collision with power lines (9.1%), shooting (9.1%), drowning (9.1%), collision with other man‐made infrastructure (6.1%), and disease (3.0%). Deaths were most frequent during the early breeding season. Only 2 (6.1%) of 33 deaths recorded occurred within a protected area. Natural causes of mortality were more frequent away from the Mediterranean coast. In contrast, anthropogenic deaths were more frequent near the Mediterranean coast, where human population density is high. We estimated that probability of extirpation of the species in our study area is 17.8% in the next 50 years and 99.2% in 100 years. Nonetheless, a small reduction in adult mortality by ≥15% could prevent extirpation in the next 50 years. Therefore, actions to reduce adult mortality are urgently needed to preserve the Bonelli's eagle in eastern Spain.

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Guiding local-scale management to improve the conservation of endangered populations: the example of Bonelli’s EagleAquila fasciata

Cited by 4 publications

References 51 publications

Sustaining Increasing Wintering Raptor Populations in Central Israel: A 38 Years Perspective

Sustaining Increasing Wintering Raptor Populations in Central Israel: A 38 Years Perspective

Potential negative effects of the installation of video surveillance cameras in raptors’ nests

A comprehensive analysis of spatial and temporal patterns of anthropogenic adult mortality of Bonelli's eagles in eastern Spain

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