Impacts of power infrastructure
This project mitigates the impacts of power generation and transmission infrastructure on birds and other biota. Initial attention was focused on collision impacts associated with powerlines, which mainly affect large, open-country birds such as bustards and cranes that are unable to react rapidly when they encounter aerial obstructions. More recently the project has considered the impacts of renewable energy technologies, including wind and solar power generation.
Wind and solar power generation have much less broad-scale environmental impact than the coal-fired power stations on which South Africa relies for most of its power generation, but both technologies can have significant impacts at a local scale. The aim of this programme is to provide practical solutions to reduce the impacts of renewable energy projects, as well as energy transmission infrastructure, on birds in southern Africa. The programme is run in collaboration with BirdLife South Africa’s Birds and Renewable Energy programme and the Endangered Wildlife Trust (EWT). Modelling the impacts of wind farms on eagles and vultures is reported separately in Conserving Verreaux’s Eagles and Vulture Conservation.
Activities in 2020
- Former CB MSc student Christie Craig, now based at the Endangered Wildlife Trust, began a study on the viability of Blue Cranes Anthropoides paradisea in the Western Cape and Karoo at the end of 2018. She registered for a PhD at the start of 2020. Powerline collisions are one of the main threats to Blue Cranes. During 2020, Christie repeated quarterly surveys of 160 km of powerlines in the Karoo, finding 72 bird collisions, 33 of which were Blue Cranes. In December 2020, she repeated 155 km of Jess Shaw’s Overberg powerline survey from 2008 as part of her CB MSc. There were only 8 Blue Cranes among 21 mortalities, far fewer than the 64 Blue Cranes out of 114 mortalities found by Jess in 2008. In 2021, Christie will try to understand this discrepancy by sampling more lines in the region to assess whether the current set of lines are representative of the Overberg as a whole, or whether increased line marking has greatly reduced mortality rates.
- In August 2020, Christie and the EWT team fitted 7 Iridium satellite tracking devices to Blue Cranes in the Western Cape, adding to the 15 devices already deployed over the last five years; a further 8 devices will be fitted in winter 2021. Movement data from these birds will be used to help assess Blue Crane powerline collision risk.
- In 2019, Christie conducted interviews with 22 farmers to understand how the agricultural landscape is changing and how this could affect cranes. Plans to interview more farmers in 2020 were postponed until 2021 due to the pandemic.
- Over the last two years, Blue Crane breeding success in the Overberg and Swartland has been 0.49 chicks per pair, only half the fledgling rate in the grasslands and Karoo. The mechanisms leading to nest failure are not clear, and we are looking to recruit a MSc student to investigate possible causes of low breeding success, including the possible impact of climate warming.
- Robin Colyn’s proposal to upgrade his MSc to a PhD from Jan 2021 was approved. His study is aimed at better understanding the factors determining the distributions of range-restricted larks in the Karoo and montane grassland regions of southern Africa. The Red Lark Certhilauda burra is a species of particular concern, given the large number of wind energy projects planned in the range of this localised, vulnerable species, and the high mortality rate of larks that undertake aerial displays at windfarms. Despite the challenges of the COVID-19 lockdowns, he completed his fieldwork in the Karoo, and made good progress with drafting papers towards his thesis.
- Robin also started to analyse the long-term movements of Ludwig’s Bustards Neotis ludwigii equipped with satellite transmitters by Jess Shaw in 2010-11. Three of her bustards are still transmitting data, with Ludwig, the first bustard to be tagged, having been tracked for more than10 years. It is fascinating to see how rather than being erratic nomads, each bustard appears to have a few preferred sites which they move between in relation to seasonal rainfall patterns.
- Sanjo Rose completed a first field season working on Agulhas Long-billed Lark Certhilauda brevirostris in the Overberg. Sanjo’s MSc project seeks to understand the breeding ecology and habitat use of this endemic range-restricted lark species which is poorly studied with virtually nothing known about its breeding ecology. Understanding the habitat use, breeding requirements and threats to nesting can help understand the likely impact of the wind energy infrastructure on this and other ground nesting lark species in the Overberg.
- Vonica Perold, Peter Ryan and Sam Ralston-Paton’s review of bird mortality at wind energy facilities around South Africa was finally published in Ostrich. Although most casualties are raptors and swifts, 130 species of birds have been reported killed at 20 windfarms. Species accumulation models suggest that around 40% of species found in the vicinity of wind farms will be killed at least occasionally.
- Estimates of bird flight heights are crucial to assess the risk of collision mortality with wind turbines and other infrastructure. Nicolas Prinsloo, a student of Nico de Bruyn (U. Pretoria), developed a photogrammetric approach to estimate flight height from an array of linked digital SLR cameras. The system is much more accurate than a digital range-finder, but is also more cumbersome to set up and use. A paper describing the technique has been accepted for publication in the Journal of Zoology (London).
- The results of Jess Shaw’s long-term experiment to assess the efficacy of marking earth wires on transmission lines to reduce bird collision mortality in the eastern Nama Karoo was finally accepted for publication in The Condor – Ecological Applications. It shows that flappers and static flight diverters are both effective at reducing the collision rate of Blue Cranes, but have little efficacy for bustards.
- A paper highlighting the wide diversity of birds killed by wind energy facilities in South Africa was published in Ostrich.
- Finding Agulhas Long-billed Lark nests proved extremely challenging; 5 nests were found and monitored in 2020.
Endangered Wildlife Trust-Eskom Strategic Partnership, The Bateleurs, BirdLife South Africa, BioTherm Energy, Hans Hoheisen Charitable Trust, Leiden Conservation Fund, Dave Myers.
Research team 2020
Prof. Peter Ryan (FIAO, UCT)
A/Prof. Arjun Amar (FIAO, UCT)
Dr Andrew Jenkins (Avisense)
Dr Megan Murgatroyd (FIAO, UCT)
Vonica Perold (FIAO, UCT)
Samantha Ralston-Paton (BLSA)
Dr Tim Reid (ANU, Canberra)
Sanjo Rose (FIAO, UCT)
Dr Jess Shaw (Scottish Natural Heritage)
Tanya Smith (EWT)
Students: Christie Craig (PhD, UCT); Robin Colyn (MSc, UCT); Sanjo Rose (MSc, UCT).