Environmental Services

Bird Diverter Research on the Omega Sterrekus Substation

Bird Diverter Research on the Omega Sterrekus Substation

As is the nature of a lot of the projects within the Construction Environmental Management Unit, some present exciting opportunities to incorporate research into the day to day lives of the Environmental Manager on site. On a site up the West Coast of South Africa, the potential for analysing the effectiveness of ‘whirley bird repellers’ was realised, and researcher (and Environmental Control Officer) Nandi Gumede reported back on the results.


The study site

The Omega Sterrekus 765kV substation is located approximately 8 kilometres from Koeberg nuclear station in Melkbosstrand/Duynefontein. It is within Eskom owned property, however is surrounded by farming activities, mostly that of oats, wheat, canola, livestock and dairy cows. The substation also has a retention pond for storm water management which has attracted various avifaunal species. Construction activities at the substation are currently at the final stages and are considered non-intensive. Avifaunal presence at the substation has been a point of contention for a while with birds roosting, perching and defecating on the structures. This can cause damage to equipment, requiring intensive and frequent cleaning.

The following bird species are often noted on site and in the surrounding areas:

Common name

Scientific name

Speckled (Rock) Pigeon

Columba guinea

Cape Turtle-Dove

Streptopelia capicola

Laughing Dove

Streptopelia senegalensis

Red–Eyed dove

Streptopelia semitorquata

Pied Crows

Corvus albus

Booted Eagle

Aquila pennatus

Steppe Buzzard

Buteo vulpinus

Greater Kestrel

Falco rupicoloides

Rock Kestrel

Falco rupicolis

Yellow-Billed Kite

Milvus parasitus

African Fish-Eagle

Haliaeetus vocifer

Southern-Masked Weaver

Ploceus velatus

Southern Red Bishop

Euplectes orix

Yellow Bishop (Yellowrumped Widow)

Euplectes capensis

The contractor on site decided to install ‘Whirly Bird Diverters’ on two study areas to determine the effectiveness of these devices in keeping birds away from the substation and preventing the associated maintenance of equipment. The two site areas were the blast walls of the transformer and the busbar reactors. There were 4 bird repellers placed each study site. These study sites were chosen as one is close to the retention pond and the other close to the wheat fields and both have a high amount of bird faeces which is considered a sign of high bird activity.


Whirly Bird Diverters are designed to be mounted on walls, and the movement  and noise of the blades as well as the reflection of the tubes are intended to repel birds from the areas they are mounted.



Visual monitoring of the entire site was conducted in morning, mid-day and afternoon segments. Photographs, videos and general field notes were kept and analysed to determine the effectiveness of the diverters. The floors and equipment were cleaned before the research period which also aided in giving a visual representation of the activity of the birds.


The results

Although the aim of the research was to ascertain the effectiveness of these bird diverters, some other interesting results came from the monitoring. The researcher was able to identify which areas the birds prefer in the mornings compared to the afternoons as well as the sides of the site which are preferred (close to the retention pond or the wheat fields). These are just interesting observations, however are important to note in any research project.

The Whirly Bird Repeller, as far as bird diverters go, was not seen as an effective means of repelling birds from the substation and the equipment found at the substation. A large problem with the bird diverters was that they could not withstand strong winds, with only one diverter remaining after the research period.

Developing bird diverters for buildings is an ongoing challenge, with new techniques needing to be more effective, robust and versatile. Although the Whirly Bird Repeller was not effective on this site, it is at least a sign that other bird diverting mechanisms are needed to ensure less money and time is spent on maintenance of substations due to bird activity.  

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