Submit an article to Indago - a peer reviewed journal
Submit an article to Indago - a peer reviewed journal
Submit an article to Indago - a peer reviewed journal

Secretarybirds are loved and admired by birdwatchers, tourists, farmers and conservationists. This bird is also the first bird species which is referred to when I speak with farmers.  Secretarybirds are grassland specialists known for catching snakes and killing them by kicking them with pin-point accurate stomps of their powerful feet.  They also forage on grasshoppers, rodents, reptiles like lizards and also small birds.  They even swallow grassland birds’ eggs like those of francolins and even a Northern Black Korhaan while foraging for food and bring these back to their nests. One can often find these eggs lying in the nest which the Secretarybirds have carried back in their crops and regurgitated for their offspring.  They build their nest on top of thorny trees like thorn trees (Vachellia species) or Buffalo Thorn trees and in some areas in the Free State also in Olive Trees.  The exact nest building period is still uncertain but can be a few months and birds will spend probably an another month at the nest before egg laying begins.  They mostly lay two eggs but three egg clutches although rare do occur and some records of the successful fledging of all three chicks have been reported from a few nest attempts (de Swardt 2007).

The eggs hatched after an incubation period of 40 – 46 days and the nestlings leave the nest after an age of about 12 weeks (or 3 months), but this can vary (Dean & Simmons 2005).  Little is known of the survival of Secretarybirds and although about 409 individuals have been ringed in Southern Africa, only about 17 recoveries and 9 retraps were reported (unpublished SAFRING data). Recently, with the aid of patagial tagging and using satellite transmitters more light has been shed on this species movements and survival during recent years (Whitecross et al. 2019).

Since 1989, I monitored more than 15 Secretarybird nest attempts in the Bloemfontein district as part of field work projects for the National Museum. In several nests the breeding cycles were mostly followed (see de Swardt & van der Westhuizen 2015).  In total, 33 Secretarybird nestlings were ringed in the Free State and later individuals were also fitted with patagial tags to study their movements.  Usually the nests were then monitored and the nestlings then ringed at an age of 7 – 8 weeks (the nestlings can stay up to 3 months in the nest). One tagged nestling, ringed at the Klein Rusplaas farm along the Jagersfontein road was first resighted several months later in the Senekal area and after 5 years this individual was again observed and photographed in the Delmas areas (de Swardt 2016).  This individual is the oldest known Secretarybird to date.  During the same period BirdLife South Africa (SA) initiated a study to monitor their movements by using satellite and GSM-cellular transmitters as Secretarybirds had been classified as Near Threatened on the national Red data list for bird species. The tracking devices enabled BirdLife SA to monitor the post nestling movements of Secretarybirds at high-resolution intervals (15 minutes to one hour) with data being transmitted back to the scientists via the cellular network and internet.  In the Free State there have already been 5 Secretarybird nestlings fitted with tracking devices since 2012. One Secretarybird, Taemane from a nest in the Warden area in the eastern FS  moved to the KZN coast (south of Scotborough) and then moved back to within 35 km of its natal nest site only two years later (Whitecross et al 2019). This bird went on to breed successfully at the age of two years and nine months and was the first Secretarybird to be followed from hatching to breeding.

During August 2019 I was lucky (because it is not every day that building activities in this species can be observed) to observe nest building activities of Secretarybirds on the farm Klein Rusplaas about 30 kilometres south of Bloemfontein on the Jagersfontein road.  While bird atlassing for the SABAP2 project I noticed 2 Secretarybirds collecting sticks and flying to a Buffalo Thorn tree. They also did courting displays on the nest and I was holding thumbs that there would be a successful nest attempt.  Usually during drought conditions when food is scarce, the adults tend to desert nests leading to unsuccessful nest attempts. My second visit to the nest site could only be done during October 2019 and I found that the nest contained a clutch of 2 eggs.  As the incubation period is mostly about 40 days, my next visit to the nest was during mid December 2019 when only one 3 week old nestling was in the nest.  As I am aware that BirdLife SA is doing a project on Secretarybirds I notified Melissa Howes-Whitecross about the breeding activity.  As the nestlings still had some down and feathers were only starting to grow, it was arranged with BirdLife SA to ring the nestling and to fit a satellite transmitter towards the end of January 2020 when the chick would be at least 7 – 8 weeks old. The tracking device was kindly donated by Dr Patrik Byholm (NOVIA University, Finland and Dr Caroline Howes (University of the Witwatersrand) who are collaborating on the Secretarybird project.

On 27 January 2020 Dawie and Lots Morapedi were joined by Dr Melissa Howes-Whitecross (Birdlife SA), Caroline Howes  and Patrick Byholm to ring the ca 7 week old nestling and fit a satellite transmitter to the nestling.  Usually the nestlings get names and this one on the farm on the Jagersfontein road was named “Cassanovia”. , because of the Finnish involvement who sponsored the tracker. The Secretarybird was removed from the nest, ringed and biometric data collected.  The bird weighed a mere 3.31 kg which is well in the 2.7 – 3.5 kg range of nestlings previously ringed by me in the Bloemfontein area. After the transmitter was fitted secure on its back the nestling (or “Cassanovia”) was returned to its nest.

We will monitor the whereabouts of the nestlings in the following few weeks and we are keen to see how long he will survive and where he will wander around.  Valuable data can be obtained from the tracking device, e. g. which types of habitats it covers, how long it stays in the nest area before wandering further away and even if he will return to the same areas over a couple of years . This is also the fourth breeding attempt of Secretarybirds in this immediate area over several years, possibly suggesting that it could be the same breeding pair.

Further reading

de Swardt, DH 2007. Another record of a Secretarybird Saggitaruis serpentaruis pair raising three nestlings in the Free State, South Africa.  Gabar 18 (2): 9-16.

de Swardt, DH & van der Westhuizen A. 2015. Secretarybird Sagittarius Serpentarius ringing in the Free State and Eastern Cape: movement data on patagial-tagged nestlings. Gabar 26: 8-10.

de Swardt DH 2016. Secretarybird Sagittaruis serpentaruis resighted after 5 years. Biodiversity Observations:7.26:1-2

Dean WRJ & Simmons RE 2005. Secretarybird Sagittaruis serpentaruis In: Hockey PAR, Dean WRJ, Ryan PG. (Eds). Roberts – Birds of Southern Africa (VIIth Ed) Cape Town: The Trustees of the John Voelcker Bird Book Fund. pp. 542-543.

Whitecross, MA, Retief EF & Smit-Robinson HA 2019. Dispersal dynamics of juvenile Secretarybirds Sagittarius serpentarius in southern Africa.  Ostrich: 90: 97-110.

Figures to use (not all need to be used – option of selection):

Figure 1: Secretarybird nest with 3 egg clutch.

Figure 2: Nestling of 8 week old nestling (Petrusburg, 2014)

Figure 3: BLSA and NOVIA team

Figure 4: Sattelite transmitter fitted on Secretarybird back.

Figure 5: Dawie de Swardt and Lots Morapedi of the Ornithology Department at the nest tree at Klein Rusplaas, Jagersfontein road.

Back ground picture: Secretarybird in grassland (Melissa Howes-Whitecross)

Comments are closed.