Talks and projects - Secretary bird talk


On the evening of the 11th September 2019, we had the privilege to listen to Dr Melissa Howes-Whitecross from Birdlife SA talk about the 2019 bird of the year, the Secretary bird (Sagittarius serpent Arius). Some more info on these amazing birds for those who could not join us.

The Secretary bird is a charismatic and familiar species, and uses a variety of open habitats across its range in sub-Saharan Africa. It occurs in all nine provinces in South Africa. The Secretary bird is assigned to its own family, Sagittariidae – an endemic African family found nowhere else on earth. The Secretary bird is easy to identify; it has long legs, grey-black plumage, crest feathers and orange facial skin. In flight its long elongated central tail feathers are characteristic. The Secretary bird is an effective hunter, striding across the landscape in search of prey which when sighted are usually stunned or killed with a series of rapid and accurate kicks with a force up to five times the mass of the bird itself. Their diet consists mainly of arthropods including locusts, beetles and spiders (87%), rodents (3.9%), lizards (3.3%), birds (1.8%) and despite being well known for their ability to kill snakes, these only make up a small proportion of their regular diet (1%). Breeding can take place at any time of the year but appears to be linked to rainfall. Nests are constructed as large, flat stick structures in the tops of flat thorn trees or dense bushes approximately 3-6 m above the ground. Broods can have up to three chicks and in a good year both parents will be able to fledge all three individuals.

The Secretary bird (Sagittarius serpent Arius) was moved up the list from Near-threatened to Vulnerable in 2011. In South Africa there is considerable concern about the conservation status of the species. A preliminary analysis of SABAP1 and SABAP2 data shows a considerable reduction in the areas this species previously occupied. In Botswana a recent road count survey showed that in just a few decades the counts for the species had reduced by 78% (Garbett et al. 2018). Secretary birds face a numerous range of threats the biggest of which is undoubtedly habitat loss through the degradation of natural areas and conversion of areas into agricultural properties or human settlements. A number of fatalities have been recorded from collisions with power infrastructure and fence lines as well. Birds also face risks from collisions with motor vehicles, drowning in farm dams and secondary poisoning by consuming poisoned prey.

Birdlife South Africa initiated research on the Secretary bird in 2011 under the guidance of Ernst Retief and Dr Hanneline Smit-Robinson in order to understand aspects of the species biology which could assist with its conservation. This research included tracking the movements of Secretary birds using GPS-GSM solar-powered tracking devices. With these devices, the movement of individual birds was determined in great detail. These devices provide accurate locations to within 10 m every 15 minutes from sunrise to sunset. Not only is it possible to determine long distance movement patterns, but also habitat use and territory size.

Dr Melissa Whitecross took over the project at the start of 2018 and analyzed the large tracking dataset into a publication titled ‘Dispersal dynamics of juvenile Secretary birds Sagittarius serpent Arius in southern Africa’ which was published in Ostrich in 2019. This paper illustrates the vast distances which juvenile Secretary birds are able to travel and provided the first evidence of the age of first breeding through a bird called Taemane.

Birdlife South Africa has set up a citizen science project with two objectives. The first is to monitor sightings of Secretary birds around South Africa as part of the Bird of the Year 2019 initiative using the app BirdLasser. The second is a breeding database where citizen scientists can submit sightings of breeding Secretary birds. We encourage everyone to contribute to these valuable datasets.

For more info, visit the Birdlife SA webpage (https://www.birdlife.org.za/what-we-do/environmental-education/bird-of-the-year-2019/)