A preliminary survey of avian mortality on power lines in the Overberg, South Africa

Shaw, Jessica M.; Jenkins, Andrew R.; Ryan, Peter G.; Smallie, Jon J.

doi:10.2989/00306525.2010.488421

Cited by 20 publications

(10 citation statements)

References 5 publications

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“…The number of vultures killed by collisions is thought to be significantly under-recorded as they rarely cause electricity supply faults and are therefore not investigated, and the vast majority of vulture carcasses are likely to be removed by terrestrial scavengers before they are detected [16], [18]. If the estimate of only 2.6% of power line mortalities of blue cranes Anthropoides paradiseus and Denham’s bustards Neotis denhami being recorded in part of South Africa [53] is repeated for Cape vultures, then such a prevalent unnatural mortality factor is likely to cause severe population declines [16] as witnessed in other species [54]. For example, negative interactions with power lines are a major cause of mortality in Spanish imperial eagles, particularly in sub-adults which frequently perch on electricity pylons in areas lacking suitable alternatives [50].…”

Section: Discussionmentioning

confidence: 99%

Do Power Lines and Protected Areas Present a Catch-22 Situation for Cape Vultures (Gyps coprotheres)?

Phipps

Wolter²,

Michael

et al. 2013

PLoS ONE

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Cape vulture Gyps coprotheres populations have declined across their range due to multiple anthropogenic threats. Their susceptibility to fatal collisions with the expanding power line network and the prevalence of carcasses contaminated with illegal poisons and other threats outside protected areas are thought to be the primary drivers of declines in southern Africa. We used GPS-GSM units to track the movements and delineate the home ranges of five adult (mean ±SD minimum convex polygon area = 121,655±90,845 km2) and four immature (mean ±SD minimum convex polygon area = 492,300±259,427 km2) Cape vultures to investigate the influence of power lines and their use of protected areas. The vultures travelled more than 1,000 km from the capture site and collectively entered five different countries in southern Africa. Their movement patterns and core foraging ranges were closely associated with the spatial distribution of transmission power lines and we present evidence that the construction of power lines has allowed the species to extend its range to areas previously devoid of suitable perches. The distribution of locations of known Cape vulture mortalities caused by interactions with power lines corresponded to the core ranges of the tracked vultures. Although some of the vultures regularly roosted at breeding colonies located inside protected areas the majority of foraging activity took place on unprotected farmland. Their ability to travel vast distances very quickly and the high proportion of time they spend in the vicinity of power lines and outside protected areas make Cape vultures especially vulnerable to negative interactions with the expanding power line network and the full range of threats across the region. Co-ordinated cross-border conservation strategies beyond the protected area network will therefore be necessary to ensure the future survival of threatened vultures in Africa.

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Section: Discussionmentioning

confidence: 99%

Do Power Lines and Protected Areas Present a Catch-22 Situation for Cape Vultures (Gyps coprotheres)?

Phipps

Wolter²,

Michael

et al. 2013

PLoS ONE

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“…The Endangered Wildlife Trust has records of 62 powerline collisions and two electrocutions for the period 1996–2012, but only two records of suspected poisoning incidents (EWT unpublished data). There is no obvious trend in these data, but the former is not an insignificant number, especially considering that the percentage of powerline collision incidents that are reported is low [45]. Despite the general lack of negative beliefs about Secretarybirds among commercial farmers and in traditional African belief systems, human disturbance is suspected to be one of the main causes of the species' decline throughout the rest of its range [1], [2], [46].…”

Section: Discussionmentioning

confidence: 99%

Secretarybird Sagittarius serpentarius Population Trends and Ecology: Insights from South African Citizen Science Data

2014

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Data from two long-term citizen science projects were used to examine the status and ecology of a Red List species, the Secretarybird Sagittarius serpentarius (Vulnerable), in South Africa. The first phase of the Southern African Bird Atlas Project operated from 1987 until 1992, and the second phase began in 2007. The Coordinated Avifaunal Roadcounts (CAR) project began in 1993 and by 1998 had expanded to cover much of the south-eastern half of the country. Data submitted up until April 2013 were used. A new method of comparing reporting rates between atlas projects was developed. Changing reporting rates are likely to reflect changes in abundance; in this instance the data suggest that the Secretarybird population decreased across much of South Africa between the two atlas projects, with a widespread important decrease in the Kruger National Park. Habitat data from the CAR project were analysed to gain insight into the ecology of the species. Secretarybirds tended to avoid transformed habitats across much of the area covered by the CAR project. In the winter rainfall region of the Western Cape, which is characterised by heavily transformed fynbos vegetation, at least 50% of Secretarybirds recorded were in transformed environments. This implies that in the Fynbos biome, at least, Secretarybirds have adapted to transformed environments to some degree. However, in the rest of the country it is likely that habitat loss, largely through widespread bush encroachment but also through agriculture, afforestation, and urbanisation, is a major threat to the species. The methods developed here represent a new approach to analysing data from long-term citizen science projects, which can provide important insights into a species' conservation status and ecology.

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“…Given that both Martial Eagle and Tawny Eagle are threatened species, classed as `Vulnerable’ in South Africa (Barnes 2000), the establishment of apparently healthy, breeding populations of eagles on Karoo power lines is considered a positive by-product of the country’s expanding power grid (Boshoff 1993, Anderson 2000, Jenkins et al 2005). This operates in contrast to known negative impacts of power lines on these and other threatened birds, such as mortality in collisions with conductors or earth wires, or in electrocutions on live hardware (Lehman et al 2007, Jenkins et al 2010, Shaw et al 2010, Jenkins et al 2011, Guil et al 2011).…”

Section: Introductionmentioning

confidence: 96%

Brokering a settlement between eagles and industry: sustainable management of large raptors nesting on power infrastructure

Jenkins¹,

Goede²,

Sebele³

et al. 2013

Bird Conservation International

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Brokering a settlement between eagles and industry: sustainable management of large raptors nesting on power infrastructure. SummaryIn the Karoo region of South Africa, eagles nesting on high voltage power pylons are responsible for frequent short-circuits or faults, which reduce the quality of commercial power supply and escalate costs to the country's energy supplier, Eskom. Between 2002 and 2006 we conducted annual helicopter surveys of eagle nests on 1,400 km of power line and located 139 large nest structures, making up 96 eagle territories occupied by three species: Martial Eagle Polemaetus bellicosus (66 pairs), Verreaux's Eagle Aquila verreauxii (13 pairs) and Tawny Eagle Aquila rapax (17 pairs), and detailed 357 pair-years of breeding activity, including 241 breeding attempts. Roost sites and active nests were associated with line faulting, and more so at particular pylon configurations. We developed a three-step management plan to reduce eagle-related faulting while still accommodating eagles on the power lines: (i) all (potentially) problematic nests were relocated from high-risk positions above the power conductors, to specially provided platforms placed below the conductors; (ii) perch deterrents were installed above the conductors on all nest pylons and on high-risk pylons up to 10 structures on both sides of each nest tower; and (iii) the welfare of the eagles was monitored before and after management. In this way, line faulting was reduced on actively managed lines by > 75%, with no obvious deleterious effects on the eagle population. The study revealed that: (i) power lines can support substantial breeding populations of threatened large raptors, (ii) these birds can be a source of commercially significant line faulting, and (iii) nest relocations and perch deterrents are effective in reducing faulting without negatively impacting eagle populations.

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A preliminary survey of avian mortality on power lines in the Overberg, South Africa

Cited by 20 publications

References 5 publications

Do Power Lines and Protected Areas Present a Catch-22 Situation for Cape Vultures (Gyps coprotheres)?

Do Power Lines and Protected Areas Present a Catch-22 Situation for Cape Vultures (Gyps coprotheres)?

Secretarybird Sagittarius serpentarius Population Trends and Ecology: Insights from South African Citizen Science Data

Brokering a settlement between eagles and industry: sustainable management of large raptors nesting on power infrastructure

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