AVIFAUNAL IMPACT ASSESSMENT. October WildSkies Ecological Services (Pty) Ltd

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1 ARIES-HELIOS 765 kv OVERHEAD POWER LINE AVIFAUNAL IMPACT ASSESSMENT October 2013 Compiled by: Jessica Shaw & Jon Smallie WildSkies Ecological Services (Pty) Ltd Submitted to: Judith Alford Mokgope Consulting

2 EECUTIVE SUMMARY This report evaluates the likely impact of a proposed 765 kv overhead transmission line between the Aries Substation (south-west of Kenhardt) and the Helios Substation (north of Loeriesfontein), a distance of approximately 168 kilometres. This area is a stronghold for several large terrestrial bird and raptor species, the most important of which are Ludwig s Bustards Neotis ludwigii, Kori Bustards Ardeotis kori, Secretarybirds Sagittarius serpentarius, Northern Black Korhaans Eupodotis afraoides, Karoo Korhaans Eupodotis vigorsii and Martial Eagles Polemaetus bellicosus. In addition to being classified as threatened regionally and in some cases globally, most of these species are facing significant threats to their survival from the existing transmission lines in the study area. Systematic mortality data collection on the existing AriesHelios 400 kv line has highlighted these issues, and it is against this background knowledge that this assessment has been conducted. Likely interactions between birds and the proposed power line include destruction of bird habitat, disturbance of birds during construction, electrical faulting caused by birds, nesting of birds on the towers, and collision of birds with the overhead cables. Of these, the last two are of most concern for the proposed project. Large eagles are likely to nest on the proposed power line if a suitable tower structure is used, which will place them at risk of collision with these lines (as had already been seen on the existing Aries-Helios 400 kv line), and other interactions such as possible effects of electromagnetic fields on breeding success. If not managed according to Eskom policy and national and provincial legislation by Eskom there could be impacts on these nests and the breeding birds during the operation of the power line. Large eagles already nest on existing power lines in the area, and there is a risk that these birds breeding could be disturbed during the construction of the new line if in close proximity. Since this report recommends placing the new line adjacent to the existing line as far as possible, disturbance of any birds nesting on the existing line is likely. However, by far the most important expected interaction of the proposed line is that of bird collision. There is already considerable concern for the numbers of birds killed through collision on the existing lines in the area, particularly of Ludwig s and Kori Bustards. The addition of another line has serious implications for these bird species. It is therefore of critical importance that this risk is carefully managed if this line is to be built without significant additional impact on species already under pressure from power line impacts. Management of this risk will require the following measures: The option of recycling or upgrading the existing 400 kv line instead of building a new line should first be fully examined, and the findings of that exercise should be made available to all concerned. If the above thorough examination of the recycle/upgrade reveals that it is not viable, then the next best choice will be to ensure that the correct route is chosen. The recommended alternative (Alternative 1) should be selected, and the new power line constructed to run directly adjacent to (not more than 150 metres between outer conductors) the existing 400 kv line. All ephemeral pans and a buffer around them of at least 100 m should be avoided by the alignment. Given our current inability to accurately predict which sections of line pose a high collision risk, a suitable antibird collision line marking device must to be fitted on earth wires from pylon to pylon for the entire length of the power line. It is extremely important that Eskom identify an effective and durable marking device and installation method by the time this line is constructed. This includes the need to have a suitable and approved nocturnal device for those sections of line close to pans likely to hold flamingos. On previous projects of this nature, Eskom have argued that no approved nocturnal device exists at the time of construction with the result that no such 2

3 devices were installed. This is no longer an acceptable excuse. It is Eskom s responsibility to ensure that such a device exists in time for construction of this line. It is essential that an avifaunal walk through is conducted during the development of the site specific Environmental Management Plan for the line, and is particularly important that Eskom allows sufficient time and budget for this study to be thorough. This is critical to identify and mitigate for large eagle nests on the existing line and elsewhere on site, and to develop management recommendations to ensure that as far as possible these birds are not disturbed during the construction of the new line. The walk through will also identify sections of line that pose a high collision risk for birds which fly at night so that they can be marked with nocturnal devices. It will be Eskom s responsibility to ensure that the line marking devices remain in working order or are replaced timeously throughout the lifespan of the power line. It will be essential that a sample of the line is monitored at least every three months during the first three years of its operation in order to detect any collision hot-spot areas, and evaluate the effectiveness of the mitigation measures. This monitoring should best be done by the Eskom-Endangered Wildlife Trust Strategic Partnership. Although this recommendation may appear stringent, in our opinion the fact that systematically collected data on the collision impact and effectiveness of mitigation measures of existing lines is not more widely available is unacceptable. There is no available data on collision rates of 765 kv lines in South Africa since no systematic monitoring has been conducted to date. This means we do not know how significant collisions might be on such a large structure and must estimate using collision rates from lower voltage lines such as 400 kv. This situation can no longer be accepted when conducting EIAs for new lines. All construction, maintenance and decommissioning activities in any natural habitat along the route of the power line should be carried out in accordance with best environmental practice principles so as to minimise disturbance of any natural habitat. Particularly sensitive areas will also be identified during the avifaunal walk through process. All nests on this line (and others) should be managed according to Eskom Transmission nest management guidelines and relevant provincial and national legislation. We have not been advised of the potential tower type, but recommend cross rope suspension towers to minimise the available perching and nesting substrate and hence issues for large eagles. This configuration does not provide much nesting area, and will also reduce risk of faulting. Of these recommended management measures, the most important is that of evaluating the option of upgrading the existing line to achieve the necessary 765 kv. This evaluation is needed in order to determine whether the necessary network strengthening can be achieved without any additional length of transmission line being built, and also to strengthen and document the thinking behind this decision. 3

4 SPECIALIST DETAILS Professional registration and experience The Natural Scientific Professions Act of 2003 aims to Provide for the establishment of the South African Council of Natural Scientific Professions (SACNASP) and for the registration of professional, candidate and certified natural scientists; and to provide for matters connected therewith. Only a registered person may practice in a consulting capacity Natural Scientific Professions Act of 2003 (20(1)-pg 14) Investigator: Jon Smallie (Pri.Sci.Nat) Qualification: BSc (Hons) Wildlife Science University of Natal MSc Env Sc University of Witwatersrand Affiliation: South African Council for Natural Scientific Professions Registration number: /06 Fields of Expertise: Ecological Science Registration: Professional Member Jon Smallie has been involved in bird interactions with energy infrastructure for 13 years. During this time he has completed impact assessments for at least 80 projects, many of which have been transmission power lines. Mr Smallie has spent a large part of his career working on bird interactions with overhead power lines in the Karoo. A total of several months have been spent periodically driving transmission power line servitudes identifying high collision risk areas. This has resulted in an understanding of where large terrestrial birds prefer to spend their time in the Karoo, and the dynamics involved in large terrestrial bird collisions. This has equipped him well for conducting this assessment. A full Curriculum Vitae can be supplied on request. Additional investigator Jessica Shaw (BSc (Hons) Ecological Sciences University of Edinburgh, MSc Conservation Biology University of Cape Town) has spent the past five years studying bird interactions with power lines in South Africa, particularly collisions, and publishing several journal papers on the subject. Following on from her MSc looking at predicting and quantifying Blue Crane collisions in the Overberg, she has just completed her PhD (Shaw 2013) on this problem for Ludwig s Bustards in the Karoo. She therefore has extensive experience in bird mortality surveys on power lines, analysis of factors affecting collisions, population effects of such mortality, censusing of large terrestrial birds, testing of bird vision and line marking devices and understanding bird movements in the arid Karoo environment. A full Curriculum Vitae can be supplied on request. Declaration of independence The specialist investigators declare that: We act as independent specialists for this project. We consider ourselves bound by the rules and ethics of the South African Council for Natural Scientific Professions. 4

5 We do not have any personal or financial interest in the project except for financial compensation for specialist investigations completed in a professional capacity as specified by the Environmental Impact Assessment Regulations, We will not be affected by the outcome of the environmental process, of which this report forms part of. We do not have any influence over the decisions made by the governing authorities. We do not object to or endorse the proposed developments, but aim to present facts and our best scientific and professional opinion with regard to the impacts of the development. We undertake to disclose to the relevant authorities any information that has or may have the potential to influence its decision or the objectivity of any report, plan, or document required in terms of the Environmental Impact Assessment Regulations, Terms and Liabilities This report is based on a short term investigation using the available information and data related to the site to be affected. No long term investigation or monitoring was conducted. The Precautionary Principle has been applied throughout this investigation. Additional information may become known or available during a later stage of the process for which no allowance could have been made at the time of this report. The specialist investigator reserves the right to amend this report, recommendations and conclusions at any stage should additional information become available, particularly from Interested and Affected Parties. Information, recommendations and conclusions in this report cannot be applied to any other area without proper investigation. This report, in its entirety or any portion thereof, may not be altered in any manner or form or for any purpose without the specific and written consent of the specialist investigator as specified above. Acceptance of this report, in any physical or digital form, serves to confirm acknowledgment of these terms and liabilities. Signed on the 14 October 2013 by Jon Smallie in his capacity as specialist investigator. 5

6 1. INTRODUCTION 1.1 Background to the current study This study forms part of an Environmental Impact Assessment for the construction and operation of a 765 kv transmission line from Aries (near Kenhardt) to Helios (near Loeriesfontein). The transmission line will be approximately 168 kilometres in length. Mokgope Consulting (Mokgope) was appointed to conduct the EIA and subsequently appointed WildSkies Ecological Services (WildSkies) to conduct the specialist avifaunal study, since a project of this nature has the potential to impact on birds. Typically a project of this type could impact on birds as follows: collision of birds with overhead cables and in particular earth wires, disturbance of birds during construction and maintenance, destruction or alteration of bird habitat during construction and maintenance, electrical faulting on the line caused by birds, and the potential for birds to nest on the proposed power line. By far the most significant issue for this proposed power line is that of collision of large terrestrial birds (particularly Ludwig s Bustards Neotis ludwigii and Kori Bustards Ardeotis kori) with the overhead cables. These species are already severely impacted in the Karoo by existing transmission lines (including Aries-Helios 400 kv), and probably cannot afford to suffer significant further mortality (Shaw 2013). This will be elaborated on in this report. This site has extremely open habitats, dominated by short vegetation and pans. As such it attracts the large terrestrial bird species and raptors that typically interact with power lines such as this proposed line. Overall a total of 226 bird species have been recorded in the broader study area (although survey effort in this region is very low), of which 18 are Red-listed species (Barnes 2000). These species will be the focus of this study. 1.2 Terms of reference The terms of reference as given to WildSkies by Mokgope were as follows: Provide status of bird habitats in the area and any endangered species including their migration patterns; Identification of areas where bird interactions may play a major role; Identify conservation worthy areas and how the proposed development can avoid them; Classification of potential bird impacts, if any, on the proposed infrastructure and infrastructure impacts on bird species in the area; Provide recommendations on how to mitigate potential impacts on both birds and the proposed infrastructure Recommendation of the best alternative route and technology to be used. 6

7 1.3. Description of proposed development The proposed power line will be approximately 168 kilometres long (Figure 1). The line will consist of towers in the region of 48 metres tall and an average of 400 metres apart. The required servitude will be 80 metres wide. Three main alternative routes have been proposed for assessment, with a 4 kilometre wide corridor available for assessment. Although the tower structure has not yet been finalised, we recommend that the cross rope suspension tower be used for reasons explained elsewhere in this report. Figure 1. Layout of the Aries-Helios 765 kv power line study area in relation to towns, district roads and existing high voltage power lines 1.4. Sources of information The following information sources were consulted: 7

8 Bird distribution data from the South African Bird Atlas Projects 1 and 2 (SABAP 1 and SABAP 2) were obtained to ascertain which bird species occur in the study area (Harrison et al. 1997, SABAP ). The conservation status of all bird species occurring in the study area was determined using The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland (Barnes 2000) and the IUCN Red List for Birds (BirdLife International 2013). The power line bird mortality incident database (Central Incident Register) of the Eskom-Endangered Wildlife Trust Strategic Partnership (Eskom-EWT) was consulted to determine which of the species occurring in the study area are typically impacted upon by power lines (data from 1996 to 2012; Eskom-EWT 2012). A description of the vegetation types occurring in the study area was obtained from The Vegetation of South Africa, Lesotho and Swaziland (Mucina & Rutherford 2006). The Coordinated Avifaunal Road count project was consulted (Young et al. 2003). The Important Bird Area programme of BirdLife South Africa was consulted (Barnes 1998, and recent updates of the Important Bird Areas Directory downloaded from BirdLife South Africa 2013). The Coordinated Waterbird Count (CWAC) project (Taylor et al. 1999) data was examined for information on water bird abundance in the area. Through a field investigation (conducted during April 2013), information at the micro-habitat level was obtained first hand by driving the proposed route, as close to the alignment as roads would allow, and examining sections of particular concern. The authors have extensive field experience in the study area and significant expertise in the field of power line collisions affecting large South African birds. This includes a total of several months each in the field surveying high voltage power lines for bird impacts in the Karoo. Jessica Shaw has just completed a PhD on power line collisions in the Karoo (Shaw 2013), particularly in relation to Ludwig s Bustard. Data from Jessica Shaw s PhD thesis have been used; she surveyed a 52 kilometre section of the Aries-Helios 400 kv line (which lies in Alternative route 1) for two years to measure the number of bird collisions, and has also monitored live bird numbers in the area. She spent a total of one month in the exact study area of this proposed power line, gaining good first-hand knowledge of the area Assumptions and limitations There are now several transmission lines of this size running through the central Karoo and one wonders just how many such lines are needed, and whether more efficient use of the network cannot be made. Certainly one would expect that at some point (hopefully soon) Eskom would have enough transmission lines connecting supply areas to demand areas in this country. However, for the purposes of this study we assume that this power line is actually needed, and that effective long-term network planning has been conducted. It is however a recommendation elsewhere in this report that the option of upgrading or recycling an existing 400 kv line is examined further. This study made the assumption that the sources of information discussed above are reliable, but the following factors may potentially detract from the accuracy of the predicted results. The Atlas of Southern African Birds (Harrison et al. 1997) data is quite old now (covering the period ), and bird distribution patterns fluctuate continuously according to availability of food and nesting substrate, and environmental conditions. While data is available from both 8

9 SABAP 1 and SABAP 2, it is probably not comprehensive because this area of Bushmanland is amongst the least surveyed areas of the country due to its remoteness from large settlements where birders reside (SABAP ). Various other inaccuracies could exist in this atlas data; for a full discussion of these see Harrison et al. (1997). In addition, no long term, verified data of species distribution at a micro-habitat level along the proposed power line route exists, except what was observed during the field visit and during field work related to Jessica Shaw s PhD (Shaw 2013). The EIA process for transmission lines of this type in South Africa relies heavily on existing information, and this avifaunal study is no different. Field work was conducted in order to examine specific areas and ground truth information, but by necessity much of the information used is obtained from various existing sources (see 1.4) in order to make an educated assessment. Invariably, the existing information on birds is obtained over a far longer period and far more representative conditions than the short term EIA study. Field work cannot incorporate landowner visits and interviews for a project of this size, and invariably the time is split unevenly throughout the study area. This is particularly so for this study since the authors have extensive experience in some areas of the study area and less in others, so this current study focussed on the less well known parts. 2. DESCRIPTION OF BASELINE CONDITIONS 2.1 Vegetation description It is widely accepted that vegetation structure is more important in determining bird habitat than the actual plant species composition (Harrison et al. 1997). The description of vegetation presented in this study therefore concentrates on factors relevant to the bird species present, and is not an exhaustive list of plant species present. The following description of the vegetation types occurring in the study area makes extensive use of information presented by Mucina and Rutherford (2006). The study area lies in the Bushmanland bioregion and is dominated by Bushmanland Basin Shrubland, with patches of other vegetation types as shown in Figure 2. The grassy and shrubby vegetation in the study area is predominantly low and open, with salt pans (vloere) and occasional rocky koppies. This low vegetation is suited to species which favour open landscapes, such as bustards, korhaans, Secretarybirds Sagittarius serpentarius and a host of smaller species such as larks. Raptors also flourish in these areas provided that suitable perches exist. 9

10 Figure 2. Vegetation classification at the site of the proposed Aries-Helios 765 kv power line (Mucina & Rutherford 2006) 2.2. Bird micro-habitats Whilst much of the distribution and density of bird species in the study area can be explained in terms of the above broad vegetation description, there are differences that correspond to variations in habitat at the micro level. These bird micro-habitats are evident at a much smaller spatial scale than the broader vegetation types or biomes, and can generally only be identified through a combination of field investigation and experience. It is therefore important to visit the study area first hand. The following bird micro-habitats were identified during the field investigation and the authors previous experience in the area; examples can be seen in Figure 3. 10

11 Plains Much of the study area is composed of irregular rolling plains, covered with dwarf shrubland and/or grasses, with occasional small trees. This habitat is preferred by large terrestrial birds because they are relatively cumbersome when taking off, so need to be able to see for a distance in order to maintain vigilance from predators. Birds like bustards, cranes, storks and Secretarybirds spend much of their time on the ground in such areas foraging and resting. Prey items such as insects and seeds are associated with this vegetation and visibility for foraging is good in the open habitat. A host of other species also favour these areas, including raptors and small passerines. After good rains, lower lying areas can become waterlogged, increasing their appeal to more water-dependent birds, as well as increasing insect abundances. Salt pans (vloere) and intermittent river channels A major feature of this region of Bushmanland is the pans, some of which are very large e.g. Commissioner s Pan. In this arid environment, the silty or gravelly pans are normally devoid of vegetation, but fill with water after rainfall (Mucina & Rutherford 2006) when they can attract water birds, including species such as flamingos. They are important water sources in an area of the country where farm dams are very scarce. The pans often have associated river channels, which although usually dry can be important systems with a different vegetation composition to the remainder of the plains, often including woody species such as Acacia karoo. Rocky koppies This area is dotted with small rocky koppies, which can be attractive to raptors which use the favourable air currents here for flying. They provide different plant vegetation to the surrounds thereby attracting a different suite of smaller groundbased bird species. 11

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13 Figure 3. Examples of the broad landscape and micro-habitats available to birds in the study area 2.3. Bird species present in the study area The first Southern African Bird Atlas Project (SABAP 1 Harrison et al. 1997) and the second atlas project (SABAP 2 recorded a combined total of 226 bird species across the broad study area. This does not mean that all of these species do occur on the alignments of the proposed power line, but it does give an indication of what could occur in the area. The full species list is shown in Appendix 2 (although little survey effort has been put into this region because it is so sparsely populated, so we regard this is as a conservative list). Table 1 is an extract of the species thought to be most important for this study, including Red-listed species and additional non Red-listed species which the authors believe are relevant to this study because of their propensity to interact with overhead transmission lines. A total of 68 species are included in Table 1, with 10 listed as regionally Vulnerable, 8 as regionally Near-threatened (Barnes 2000), and 2 protected under the Bonn Convention (see Section 6). For each species the preferred micro-habitat, likelihood of occurring on site and relative importance of site have been assessed. An indication of the ways in which the species could interact with the proposed power line has also been presented. This is a large number of species to deal with, so in order to narrow the focus the really heavily impacted species for which this study area is important have been shaded in grey in Table 1. These species are discussed in more 13

14 detail below, and cannot afford to face additional collision threats due to new power lines, making it essential that this impact is carefully managed for this project. In addition to these, other species worthy of mention include White-backed Vultures and Blue Cranes (which might be present occasionally, although this is a marginal area for them), Black, White and Abdim s Storks, and medium-sized raptors which may perch or nest on pylons including kestrels, Black-chested Snake Eagles, Black Harriers, Southern Pale Chanting Goshawks, Steppe and Jackal Buzzards, Booted Eagles and Lanner Falcons. 14

15 Table 1. Summary of priority bird species associated with the proposed Aries-Helios 765 kv power line (most important species highlighted in grey) Likelihood of occurring on site Relative importance of site for national population of species Likely interactions with proposed power line Definite High C, HD, D Definite High C, HD, D Scientific name SABAP 1 SABAP 2 Regional conservation status Ardeotis kori VU Neotis ludwigii VU Buzzard, Jackal Buteo rufofuscus Any Probable C, HD, D, N, P Buzzard, Steppe Cormorant, Whitebreasted Buteo vulpinus Phalacrocorax carbo Anthropoides paradiseus Corvus capensis Any Probable C, HD, D, N, P Any close to water Possible Low C, D, N, P, pans Possible Low C Definite Low C, HD, D, N, P Definite Low C, HD, D, N, P Pans Unlikely Pans Unlikely Common name Bustard, Kori Bustard, Ludwig's Crane, Blue Crow, Cape VU Preferred micro habitat in this study area and Acacia watercourses Corvus albus Oxyura maccoa Anas platyrhynchos Anas undulata Pans Probable Low C Probable C, HD, D, P VU Definite High C, HD, D, N, P Eagle, Tawny Aquila pennatus Polemaetus bellicosus Aquila rapax VU Possible Low C, HD, D, N, P Eagle, Verreaux's Aquila verreauxii Probable C, HD, D, N, P Eagle-Owl, Cape Bubo capensis None Unlikely Eagle-Owl, Spotted Bubo africanus Any Probable C, HD, D, P Falco biarmicus Polihierax semitorquatus Haliaeetus vocifer Phoenicopterus ruber Phoenicopterus Definite C, HD, D, N, P Possible Low C, D, P Any close to water Unlikely NT Pans Probable C, D NT Pans Probable C, D Crow, Pied Duck, Maccoa Duck, Mallard Duck, Yellow-billed Eagle, Booted Eagle, Martial Falcon, Lanner Falcon, Pygmy Fish-Eagle, African Flamingo, Greater Flamingo, Lesser NT 15

16 minor Goose, Egyptian Goose, Spur-winged Goshawk, Gabar Goshawk, Southern Pale Chanting Grebe, Black-necked Alopochen aegyptiacus Plectropterus gambensis Melierax gabar Any close to water Definite C, D, N, P Any close to water Probable Low C, D Possible Low C, D, P Any Definite C, HD, D, N, P Pans Possible Low C Pans Possible Low C Any Definite C, HD, D, P Any Possible C, HD, D, P None Unlikely Any close to water Definite C Melierax canorus Podiceps nigricollis Tachybaptus ruficollis Numida meleagris Circus maurus Polyboroides typus Ardea melanocephala Ardea goliath Any close to water Unlikely Any close to water Probable C Any close to water Definite C, P Any close to water Probable C, P Kestrel, Greater Ardea cinerea Threskiornis aethiopicus Plegadis falcinellus Bostrychia hagedash Falco rupicoloides Kestrel, Lesser Falco naumanni Grebe, Little Guineafowl, Helmeted Harrier, Black Harrier-Hawk, African Heron, Black-headed Heron, Goliath Heron, Grey Ibis, African Sacred Ibis, Glossy Ibis, Hadeda Any Definite C, P Definite C, HD, D, N, P Probable C, HD, D, P Probable C, HD, D, P Any Probable Low P Any Probable Low P Definite High C, HD, D Definite High C, HD, D Probable to high HD, D NT Probable to high HD, D VU Any close to water Possible Low C, HD, D Any Probable C, D, P VU Falco rupicolus Kite, Yellow-billed Milvus aegyptius Korhaan, Karoo Eupodotis vigorsii Korhaan, Northern Black Afrotis afraoides Calendulauda burra Spizocorys sclateri Lark, Sclater's Marsh-harrier, African Owl, Barn Circus ranivorus Tyto alba Elanus caeruleus Lark, Red NT Kite, Black-shouldered Kestrel, Rock VU 16

17 Plover, Chestnut-banded Pochard, Southern Raven, White-necked Sandgrouse, Namaqua Scops-Owl, Southern White-faced Charadrius pallidus Netta erythrophthalma Corvus albicollis Pterocles namaqua Ptilopsus granti Pans Possible Low to medium C, D Pans Probable C Any Definite C, P, N Definite to high C, HD, D None Unlikely Definite to high C, HD, D Any close to water Definite C Any close to water Definite C Shelduck, South African Sagittarius serpentarius Tadorna cana Shoveler, Cape Snake-Eagle, Blackchested Spoonbill, African Anas smithii Circaetus pectoralis Platalea alba Secretarybird NT NT Definite C, HD, D, P Pans Probable C Bonn Any close to water Possible Low C, P NT Any close to water Possible C, P Bonn Any close to water Possible Low C, P Pans Probable C Pans Unlikely Pans Possible Low C Ciconia abdimii Stork, Black Ciconia nigra Stork, White Ciconia ciconia Anas capensis Thick-knee, Spotted Anas hottentota Anas erythrorhyncha Burhinus capensis Definite High C, HD, D Vulture, Lappet-faced Torgos tracheliotos VU Possible Low C, HD, D, P Vulture, White-backed Gyps africanus VU Possible Low C, HD, D, P Any Probable HD, D, P, N Stork, Abdim's Teal, Cape Teal, Hottentot Teal, Red-billed Weaver, Sociable Philetairus socius VU = Vulnerable; NT = Near-threatened; Bonn = Protected Internationally under the Bonn Convention on Migratory Species. C = Collision with overhead cables; HD = Habitat destruction; D = Disturbance of birds during construction; N = Nesting on towers; P = Perching on power line towers (this has relevance for the impacts discussed elsewhere in this report). 17

18 Ludwig s and Kori Bustards These physically large species are highly vulnerable to collision with overhead power lines, and are also likely to be affected by disturbance and habitat destruction. Ludwig s Bustard is a wide-ranging bird endemic to the south-western region of Africa (Hockey et al. 2005). This species was listed as globally Endangered in 2010 because of potentially unsustainable collision mortality, exacerbated by the current lack of proven mitigation and the rapidly expanding power grid (Jenkins et al. 2011, BirdLife International 2013). Ludwig s Bustards are both partially nomadic and migratory (Allan 1994, Shaw 2013), with a large proportion of the population moving west in the winter months to the Succulent Karoo. In the arid and semiarid Karoo environment, bustards are also thought to move in response to rainfall, so the presence and abundance of bustards in any one area are not predictable. Therefore, collisions are also largely unpredictable, and vary greatly between seasons and years (Shaw 2013). While there is no evidence yet of population-level declines resulting from collision mortality, detailed range-wide power line surveys estimate that tens of thousands of bustards (from a total South African population of approximately 114,000 birds) die annually on the existing power grid in this country, which is of grave concern given that they are likely to be long-lived and slow to reproduce. It seems likely that there will be a threshold power line load at which population declines will become apparent, but it is not possible to accurately predict what this will be, and such effects will probably only be noticed when it is too late to do anything about it (Shaw 2013). Therefore, extreme caution is necessary in the planning of any new power lines in the range of this species. Kori Bustards are classified as regionally Vulnerable (Barnes 2000), with an estimated population of 2,000 5,000 birds in South Africa (Hockey et al. 2005). There are also worries for the population consequences of power line mortality for this species, given that some 14% of the population are estimated to die annually on Karoo transmission lines alone (Shaw 2013). Kori Bustards in the Karoo are thought to be locally nomadic (Hockey et al. 2005) and thus likely suffer greater collision rates than more sedentary populations in other areas (e.g. the Kalahari; Senyatso 2011). If this is the case, the Karoo could be acting as a population sink for Kori Bustards, at a time when Kori numbers are thought to be decreasing throughout southern Africa (Barnes 2000, Senyatso et al. 2012). Northern Black and Karoo Korhaans Neither of these birds are Red-listed, and they are locally common in this region (Hockey et al. 2005). As sedentary species, they seem to be less susceptible to collision than the larger, more mobile bustards, but they are still frequently recorded as collision victims in the Karoo, which is their stronghold (Shaw 2013). There is some evidence that Karoo Korhaans are not as abundant as previously thought (Shaw 2013), so additional mortality caused by this proposed power line is of concern. Secretarybirds This species is classified as regionally Near-threatened (Barnes 2000), but has recently been uplisted to globally Vulnerable on the basis of population declines (BirdLife International 2013). While there is no current population estimate in South Africa, there has been a reduction of sightings in the areas it previously occupied (SABAP 2 c.f. SABAP 1 data). This is probably mainly due to habitat loss, but power line collisions may also be a significant factor. The physical attributes of Secretarybirds mean that they are highly vulnerable to collision, and data from Karoo transmission lines (Shaw 2013) and the Central Incident Register (Eskom-EWT 2012) indicate that these birds do indeed collide across their range. However, as 18

19 the population is sparsely distributed it is probably underrepresented in available collision data, and further research woul d be necessary to better understand potential population impacts of this source of unnatural mortality. Unfortunately, the species movement is not well understood so BirdLife South Africa have recently placed satellite transmitters on Secretarybirds in order to track their movements, but this data is not useful for the current study. Lesser and Greater Flamingos These species are both classified as regionally Near-threatened by Barnes (2000), with Lesser Flamingos also classified as globally Near-threatened (BirdLife International 2013). They move extensively in response to rainfall, often suddenly arriving at pans which hold water after a rainfall event, so can be expected to arrive at any such open water source in the study area. This unpredictable movement and habit of flying at night and in flocks makes them a challenging species to manage in relation to power lines. The two species are highly vulnerable to collision, with Greater and Lesser Flamingos th th listed as the 5 and 6 most commonly reported species killed by power lines in South Africa (Eskom-EWT 2012). Their vulnerability to collision is believed to be at least partially due to their tendency to fly at night, when visibility of overhead cables would be low. This factor makes it difficult to mitigate for collisions, since line marking devices designed for diurnal fliers are not effective at night. Although nocturnal marking devices exist they are not currently approved for use on transmission lines. This aspect will need to be addressed by the time of construction of this power line. Martial and Verreaux s Eagles The Martial Eagle is classified as globally Near-threatened, and regionally Vulnerable (Barnes 2000, BirdLife International 2013), whilst Verreaux s Eagle is currently non Red-listed. Both species are locally common, the Karoo being an area with a relatively high density of breeding pairs and therefore an important area for these species. They are well known to have adapted to using Eskom transmission line towers for perching, roosting and nesting. Although this appears at face value to be a positive impact (allowing the birds to expand their range into areas previously unsuitable for breeding due to a lack of trees) residing on a power line also increases the risk of collision that the birds face, particularly for young birds recently fledged (who can also become entangled and die in the tower lattice when fledging; J. Shaw pers. obs.). Although we recommend the proposed power line be constructed on a cross rope suspension tower which is unsuitable for nesting, the proposed routes of the power line pass close to an existing power line, which houses at least one existing Martial Eagle nest (J. Shaw pers. obs.), and probably many more. This new power line may pose a new collision risk within existing territories, and a possible disturbance of breeding if construction of the new line takes place during breeding season. Red and Sclater s Larks Bushmanland is renowned for its high diversity and abundance of larks, many of which are endemic to southern Africa (Hockey et al. 2005). Parts of Bushmanland boast being home to up to 14 species of lark in the same area. Of particular relevance to this study are the Red Lark and Sclater s Lark, both of which are listed as regionally threatened species (Vulnerable and Near-threatened respectively; Barnes 2000), have very restricted ranges and have been recorded in the study area (Harrison et al. 1997, SABAP ). While these birds are unlikely to interact with power lines directly, disturbance during construction could be an issue. The Red Lark is particularly confined to the red sand dunes in Bushmanland and therefore impacts on this species can be managed spatially. Areas where this species could occur will be identified during the avifaunal walk through. 19

20 2.4. Bird sightings in the study area Priority species seen during field work were recorded and can be seen in Figure 4. This figure also details birds seen in the study area during a large terrestrial bird road census which was conducted four times across the Karoo from May 2010April 2011 (Shaw 2013). The data provides confirmation of the presence of several key species in the vicinity of the proposed power line. Care should be taken not to place too much emphasis on the exact locations of the sightings, as birds in this arid environment are highly mobile, and react to very localised rainfall which can occur in this region. In addition, the field work was not representative of variation in conditions on site, and time was not apportioned evenly across the study area. Figure 4. Priority bird species recorded during field work and census counts in the study area (KK=Karoo Korhaan, LB=Ludwig s Bustard, KB=Kori Bustard, NBK=Northern Black Korhaan, ME=Martial Eagle), and the section of Aries-Helios 400 kv which was surveyed for collision mortalities; see section 2.5 (Shaw 2013) 20

21 2.5. Power line mortality surveys on Aries-Helios 400 kv Of specific interest to this study is a 52 kilometre section of the existing Aries-Helios 400 kv line which was surveyed quarterly for two full years (April 2010-April 2012) for power line mortalities as part of a wider study on the impact of power line collisions on Ludwig s Bustard (Shaw 2013). This section is completely unmarked and is part of Alternative 1; shown in Figure 4. Results from this study indicated that at least nine species are impacted by this power line (Table 2), four of which are priority species (Table 1). As expected, bustards were most affected, with high numbers of Ludwig s and Kori Bustards killed. It is well known that power line surveys will underestimate mortality rates, because of scavenger removals, habitat and observer biases (Bevanger 1999). Recent experiments in the Calvinia region of the Karoo have demonstrated that less than half of the dead birds present under power lines are likely to be located (Schutgens et al. in review, Shaw et al. in prep.) Therefore, a minimum estimate of 0.19 Ludwig s Bustards.km.yr are killed on the unmarked Aries-Helios 400 kv, but a -1-1 more realistic estimate adjusted for dead birds missed on surveys is 0.42 Ludwig s Bustards.km.yr. While these collision rates are lower than in some other areas of the Karoo (Shaw 2013), environmental conditions and therefore the number of birds present at this site vary greatly depending on rainfall, so rates could increase dramatically if large numbers of birds were in the area. While there are no data available for collision rates on 765 kv lines, if they are at least similar to the 400 kv line at this site it is likely that the proposed new Aries-Helios line will kill at least 70 Ludwig s Bustards annually, unless marked. Given the issues discussed above, such mortality rates are unacceptable. Table 2. Number of bird collisions recovered from a 52 km section of Aries-Helios 400 kv ( ) by species (data from Shaw 2013). Recent collisions are those that died in the two year study period, and total collisions include historic remains. Species Recent collisions Total collisions Ludwig's Bustard Kori Bustard 7 13 Karoo Korhaan 3 3 Egyptian Goose 1 1 Martial Eagle 1 1 Pied Crow 1 1 Spotted Thick-knee 1 1 Cape Shoveller 0 1 Sacred Ibis 0 1 Unidentified bustard 1 1 TOTAL In addition to dead birds, live Martial Eagles, Northern Black and Karoo Korhaans, and Ludwig s and Kori Bustards were commonly seen on the surveys of this section of line (J. Shaw unpublished data), highlighting the importance of this area for these species. 21

22 2.6. Important Bird Areas (IBAs), Coordinated Avifaunal Roadcount Project (CAR) and Coordinated Water Bird Counts Project (CWAC) These are three bird conservation and monitoring initiatives in South Africa. The CAR project counts large terrestrial bird species using repeated vehicle based transects (Young et al. 2003), and the CWAC project counts water birds at established sites each year (Taylor et al. 1999). The Important Bird Areas (IBA) programme identifies and conserves sites internationally that are critical for the long-term survival of bird species that are globally threatened, have a restricted range, and are restricted to specific biomes/vegetation types. Sites which have significant populations of water birds are also considered (BirdLife South Africa 2013). However, the site of this proposed power line is in a remote area of Bushmanland, and because it is very sparsely populated by people, neither CAR nor CWAC data are collected here. In addition, the proposed routes do not encompass any IBAs, with the closest one SA036 (Bitterputs Conservation Area), approximately 80 km northwest of the route. This IBA features red sand dunes and barren stony plains, and protects similar species as those found at the site currently under assessment, including the globally Vulnerable Red Lark, Near-threatened Sclater's Lark and similar raptors and large terrestrial birds (BirdLife South Africa 2013). 3. EVALUATION OF IMPACTS 3.1. General description of bird interactions with power lines Because of its size and prominence, electrical infrastructure constitutes an important interface between wildlife and man. Wildlife interactions with power lines are almost all negative, with the two main problems caused by electrocution of birds (and other animals) and birds colliding with power lines (Ledger & Annegarn 1981, APLIC 1994, Bevanger 1998, Kruger 1999, van Rooyen & Ledger 1999, Lehman et al. 2007, Jenkins et al. 2010, Shaw et al. 2010, Prinsen et al. 2011, APLIC 2012, Shaw 2013). Other issues are electrical faults caused by bird excreta when roosting or breeding on electricity infrastructure (van Rooyen & Ledger 1999), and disturbance and habitat destruction during construction and maintenance activities (e.g. Silva et al. 2010, Raab et al. 2011a). Electrocutions Electrocution of birds on overhead lines is an important cause of unnatural mortality of raptors and storks, and has been a focus of much attention in Europe, USA and South Africa (APLIC 1994, Alonso & Alonso 1999, van Rooyen & Ledger 1999, Lehman 2001, Lehman et al. 2007). Electrocution can occur when a bird is perched or attempts to perch on electrical structure and causes a short circuit by physically bridging the air gap between live components and/or live and earthed components. However, for overhead lines above 132 kv, electrocutions are not a major issue because the large clearances separating dangerous components cannot be bridged by even the largest birds (Lehman et al. 2007). Therefore, electrocution will not be discussed further in this report. 22

23 Collisions Collision with power lines is a well-known conservation problem for many birds, and for some species can be a significant source of mortality (Bevanger 1998, Erickson et al. 2005, Drewitt & Langston 2008, Shaw et al. 2010, Jenkins et al. 2011). The reasons for collisions are complex, with each case involving a variety of biological, topographical, meteorological and technical factors (Bevanger 1994). Although all birds have the potential to be affected by collisions, those most heavily impacted are generally large, flocking species which fly often, with waterfowl, gamebirds, cranes, bustards and storks usually among the most frequently reported casualties (Bevanger 1998, Janss 2000, Jenkins et al. 2010). The large body size of such species mean that they have limited manoeuvrability in the air and are less able to take necessary evasive action to avoid colliding with power lines (Bevanger 1998). In South Africa, incidentally discovered mortality incidents reported by Eskom staff, conservationists and the general public are collated in the Central Incident Register, which is maintained by the Eskom-Endangered Wildlife Trust Strategic Partnership (Eskom-EWT 2012). These data, together with those from more systematic power line surveys near De Aar (Anderson 2002), in the Overberg (Shaw et al. 2010) and across the Karoo (Jenkins et al. 2011, Shaw 2013) highlight the high levels of large terrestrial bird mortality caused by existing power lines in this country. Particularly affected are Redlisted birds including cranes, bustards, storks, Secretarybirds, flamingos and vultures, which are generally long-lived and slow to reproduce (Shaw 2013). These species have not evolved to cope with high adult mortality, with the result that consistent mortality in this age group over an extended period could seriously affect a population s ability to sustain itself in the long, or even medium term. The cumulative effects of collisions together with other anthropogenic threats to these species (e.g. habitat destruction, disturbance) are unknown over the long term. The available data on bird collisions relevant to this study have been discussed in sections 2.3 and 2.5. Mitigating bird collisions with power lines typically involves the installation of line marking devices on the cables in order to make them more visible to approaching birds. Worldwide, a variety of marking devices are used, but very few have been adequately field-tested (Jenkins et al. 2010). Great uncertainty remains about which are best, as they vary enormously in effectiveness between species and in different conditions (van Rooyen & Ledger 1999, Anderson 2002). Generally though, marking seems to be fairly effective, with a recent meta-analysis showing a 78% decrease in mortality rates on marked lines (Barrientos et al. 2011). However, bustards are particularly difficult to mitigate for. Janss & Ferrer (1998) found no evidence of a decrease in Great Bustard Otis tarda mortality following line marking in Spain, although markers did seem to be effective for Little Bustards Tetrax tetrax. Raab et al. (2011b) suggested that Great Bustards benefitted from line marking in Austria and Hungary, but the effect was minimal compared to the reduction in mortality resulting from burying power lines. Most recently, Barrientos et al. (2012) demonstrated a slight reduction in collision rates for Great and Little Bustards following marking in Spain, but rates remained high even after marking. The reason for this apparently low efficacy is likely to be a result of the visual capacity of bustards. A recent South African study on Kori Bustards demonstrated that these birds have a narrow field of frontal vision, so when in flight, head movements in the vertical plane (pitching the head to look downwards, perhaps to look for other birds or foraging patches) will render the bird blind in the direction of travel and they will not see the power line at all (Martin & Shaw 2010). This study also examined the visual capacity of Blue Cranes and White Storks, and in contrast to Kori Bustards, these species have much broader fields of view. However, the visual constraint for bustards has significant implications for collision mitigation and suggests that marking devices installed on cables themselves are unlikely to be 100% effective. Similar visual 23