An initial investigation into the electrocution of 48 Cape vultures on Eskom powerlines near Elliot, in the Eastern Cape, has indicated that noncompliant structures were responsible for the death of the endangered birds.

The two main incidents took place near one of the 20 remaining breeding sites in the Eastern Cape. A third smaller incident took place on a powerline about a kilometre away from an abattoir where birds were fed.

The State-owned electricity utility confirmed this week that some vultures had been electrocuted “at various locations in the Eastern Cape” and that a formal investigation would be initiated to determine the root cause of the deaths.

The incidents were reported directly to Eskom by Walter Neser, of AfricanVultures.org, and had since also been officially reported to the Endangered Wildlife Trust (EWT). Eskom and EWT have a strategic partnership through which mitigation measures identified during investigations were to be “implemented by Eskom to prevent further bird mortalities in this area and elsewhere”.

Neser had already completed a preliminary investigation, which had been submitted to Eskom, and mitigation work had already been carried out on the structures.

EWT and Eskom investigators would also reportedly visit the sites and would write a separate report into the incidents. A senior EWT field officer for the Wildlife and Energy Programme told Engineering News Online that the formal EWT investigation was being prioritised, owing to the scale of the incidents.

The electrocutions appeared to have taken place over a period of time, with both decayed and fresh carcasses discovered over the Easter weekend.

The incidents were also being prioritised, owing to the fact that the Cape vulture has been recently been reclassified as endangered on the ‘IUCN Red List of Threatened Species’ – previously it was listed as vulnerable.  There are believed to be about 4 000 active breeding pairs birds in Southern Africa.

“There are fewer Cape vultures left than there are rhino,” Neser warned, adding that greater urgency was needed to deal with the risk to the birds.

At both the sites, he added, the structures did not meet current Eskom specifications, as the powerlines had continuous earth lines, with no basic insulation level gap.  “This is known to be extremely dangerous for vultures and other birds landing on the structures, as their perch is earthed, so electrocution only requires contact with one of the three phases.”

Questions would also be posed, meanwhile, as to whether the lines had been properly inspected by Eskom employees to ensure that they were “bird friendly”.

The utility acknowledged that powerlines built before the introduction of its biodiversity policy, which stipulates bird-friendly designs, could present an electrocution risk to large birds.

In order for a powerline to be designated bird friendly it must not be possible for birds with large wingspans, such as vultures, to breach the gap between two live conductors, or between live and earth phases.

“In the event of bird mortalities being reported on old designs (as in this case) an investigation is performed and recommendations forwarded to Eskom by the EWT to implement mitigation measures,” Eskom said. Recommendations could also forwarded by organisations such as VulPro or AfricanVultures.org.

“In terms of Eskom’s strategy, mitigation measures will be put in place within four months of the reported incidents. Currently, 88.23% of recommendations received from the EWT were closed within 4 months.”

The utility added that it, together with EWT, had conducted research to identify bird-sensitive areas to enable it to take proactive mitigation actions. “This programme will commence within the next 12 months.”

EWT reports that, since 1996, 1 262 vulture mortalities have been recorded in the Eskom/EWT Central Incident Register.

Even prior to the Elliot incident, the most heavily impacted species had been the Cape vulture, with 774 mortalities being recorded, of which 637 were recorded as electrocutions.

Neser expressed frustration at the time it had taken Eskom to respond to a known risk to the vultures in the Eastern Cape area.

AfricanVultures.org, using tracking data provided by VulPro, produced a sensitivity assessment, which had been laid over a map of Eskom’s power grid. This tool was key to Neser unearthing the vulture electrocution incidents in the Elliot district.

“Using these risk assessment maps enables one to focus on the most important areas where incidents are most likely to occur, rather than blindly surveying the grid,” Neser argued, noting that some of the information had been available to Eskom prior to 2012.