Young Secretarybird ‘Kwezi’ killed on her first dispersal flightPosted on the 4th August 2019
The BirdLife South Africa 2019 Bird of the Year is the Secretarybird Sagittarius serpentarius. BirdLife South Africa has used this campaign to highlight the conservation of these charismatic birds of prey that are widely distributed across sub-Saharan Africa. The BirdLife South Africa Secretarybird Conservation Project started in 2011 and has tracked the movements of 13 juvenile Secretarybirds around South Africa using GPS telemetry. Mortality rates of young raptors are known to be high globally and this project has been no exception with five confirmed mortalities and a further three suspected mortalities during the study. The most recent of these was Kwezi who died at the age of only six months after colliding with overhead cables on a transmission line only 26 km from her nest near Besters, KwaZulu-Natal. Southern Africa's Secretarybird population is in trouble and urgent steps need to be taken to ensure that these regal birds which stride across the African grasslands do not become another statistic of lost biodiversity in the ever increasing global crisis.
Secretarybirds are apex predators in the open grasslands and savannas of sub-Saharan Africa. In 2011 the International Union for the Conservation of Nature (IUCN) uplisted the species from Least Concern to Vulnerable after an assessment showed evidence of a drastic decline in the size of the global population largely driven by loss of habitat. This prompted BirdLife South Africa, under the project leadership of Ernst Retief and Dr Hanneline Smit-Robinson to initiate the BirdLife South Africa Secretarybird Conservation Project. The aim of this project was to improve the understanding of the movements, dispersal and survival of juvenile Secretarybirds across South Africa. Between 2012 and 2014 ten juvenile Secretarybirds were fitted with light-weight (38 g), solar-powered, GPS-GSM telemetry devices fitted to the birds’ backs. Over 45 900 location points were collected and ground-breaking findings improved the understanding of the development and dispersal behaviour of young Secretarybirds.
|Image by Wilfred Crous|
|Image by Carin Malan|
Unfortunately a darker side of the telemetry study has been the reports of mortalities of several of the young tracked birds. The first of the confirmed mortalities was of a female bird called Artemis, who was tagged in Leeuwfontein Nature Reserve on the northern edge of Gauteng in March 2014. A mere four and a half months later, Artemis was found dead near the base of a large cliff some 350 km from her natal nest, seeming to have perished due to natural causes. The next confirmed mortality was that of BLiNG, a well-known male tagged at Sondela Nature Reserve, who gained fame after dispersing northwards to the Makgadigadi Pans within 2 weeks of leaving his natal territory. BLiNG returned to Gauteng and spent several weeks foraging in the isolated patches of grassland within the Tshwane Metropole. However, one fateful afternoon, when a fire had broken out underneath the grasslands of a large transmission line corridor, BLiNG collided with the overhead electrical cables and was killed at the age of two years and ten months. The third confirmed fatality during this study was a young female called Koffie who met her end after colliding and becoming entangled in a barb-wire fence approximately 70 km from her natal territory. Fences and powerlines are a considerable threat to young raptors and large terrestrial birds, in particular Secretarybirds.
BirdLife South Africa’s Ernst Retief is working to understand and mitigate the impacts of fences on wildlife and has produced a brochure which can provide for information about this threat. Mr Retief states that “It is likely that we are vastly underestimating the detrimental impacts infrastructure such as fences and electrical cables are having on our terrestrial birds”.
|Image by Carin Malan|
|Image by Diane Steenkamp|
In 2018 Dr Melissa Howes-Whitecross took over coordination of the Secretarybird Project and has since fitted telemetry devices to three additional juvenile Secretarybirds, two of which have already been lost to collisions with high-voltage electrical cables. Tambo, a young Secretarybird rescued from the edge of the OR Tambo International Airport runway after suffering from a severe foot infection, was rehabilitated by the Johannesburg Wildlife Veterinary Hospital for four months and released in the grasslands of Devon, Gauteng. Tambo unfortunately died after colliding with electrical infrastructure only four weeks after being released in October 2018. The most recent loss was that of Kwezi, a young bird tagged on a farm near Besters, KwaZulu-Natal after a supportive farmer contacted BirdLife South Africa to let them know that a pair of Secretarybirds were breeding on his property. Kwezi was fitted with a tracking device on 23 February 2019 at the age of approximately 8 weeks. She showed the typical developmental pattern of the previously studied Secretarybirds, exploring the environment around her natal nest in ever increasing distances. On 23 July 2019, Kwezi set off on her first major dispersal flight away from her nest and by 25 July 2019 she had travelled approximately 26 km from her natal nest. Unfortunately she would travel no further after she collided with the overhead cables of a large electrical transmission line at the age of only six months old. BirdLife South Africa’s Ingula Project Manager, Carina Coetzer, was quick to respond to the site when it was detected that Kwezi was no longer moving and unfortunately confirmed the tragic news. A post mortem showed that Kwezi had been feeding well prior to the incident with several large locusts and a dead snake found in her stomach.
BirdLife South Africa has reported the collision incident to Eskom and the Endangered Wildlife Trust and an investigation into the incident has been arranged to ensure that the root cause can be suitably identified and addressed through appropriate mitigation. In discussion with Mr Kishaylin Chetty, Senior Advisor from Eskom’s Biodiversity Centre of Excellence, he has reiterated Eskom’s commitment towards minimising the impact of Eskom’s activities on South Africa’s wildlife to ensure the long term sustainability of South Africa’s biodiversity heritage into the future. Kwezi’s death will hopefully result in the marking of the powerline, to prevent further mortalities. The attachment of bird flight diverters will increase the visibility of the lines and deter birds from colliding with them in future. Several threatened bird species have been sighted in the immediate area, including Endangered Cape Vultures, so mitigation will be critical for the powerline to prevent further mortalities.
Recent studies have shown declines of between 70-80% of Secretarybirds across southern Africa (Hofmeyr et al. 2014, Taylor et al. 2015, Garbett et al. 2018). Dr Melissa Howes-Whitecross suggests that “Secretarybirds, other raptors and large terrestrial birds are already under pressure due to the high levels of habitat loss they have experienced across the region. This coupled with the high mortality rates of young Secretarybirds is a concerning factor when considering their long-term survival and conservation. If young birds are not making it successfully into the breeding population we will see the knock-on impacts of this with a future population crash”. BirdLife South Africa is working hard to secure safe areas within the grassland biome through biodiversity stewardship to protect suitable habitat for these flagship species. The organisation will continue to work towards improving the understanding of the ecology of these charismatic birds and furthering their conservation throughout the sub-region.
The preliminary results from this study have been collated into a recent publication by the current project lead Dr Melissa Howes-Whitecross in Ostrich – Journal of African Ornithology titled ‘Dispersal dynamics of juvenile Secretarybirds Sagittarius serpentarius in southern Africa’. Future work for the project will include an assessment of suitable habitat conditions for Secretarybirds using the telemetry data and the over 450 observations collected during the Bird of the Year BirdLasser Challenge where members of the public have been encouraged to submit their Secretarybird sightings to BirdLife South Africa during 2019.
BirdLife South Africa would like to acknowledge the generous funding and support provided by the Airports Company South Africa and Petra Diamonds, both previous BirdLife International Species Champions for the Secretarybird, as well as the Ingula Partnership, a collaboration between Eskom, Middelpunt Wetland trust and BirdLife South Africa, for their support of the Raptors & Large Terrestrial Birds Project Manager. We would also like to acknowledge the assistance offered by numerous land owners, volunteers, bird clubs and conservation authorities across South Africa.
For more information contact:
Dr Melissa Howes-Whitecross, Acting Programme Manager Terrestrial Bird Conservation Programme and Threatened Species Project Manager: Raptors & Large Terrestrial Birds
tel: +27 (0)11 789 1122