fbpx

Positive Outlook for the Southern Bald Ibis


The Southern Bald Ibis Species Champion Project of BirdLife South Africa includes the monitoring of breeding colonies, an awareness program at schools within the bird’s core range, and the artificial nesting project in Ingula Nature Reserve. 

Bald ibises belong to the genus Geronticus, derived from the Greek word gérontos meaning old man—as reference to their bald heads. The non-migratory Southern Bald Ibis (Geronticus calvus) is endemic to a restricted region in southeastern Africa. The Southern Bald Ibis’ most notable feature is the clownish red skull cap, distinguishing it from its very close cousin, Geronticus eremita, the Northern Bald Ibis, which looks like an aging rockstar with a mohawk-style neck crest of elongated feathers (Conservation Frontlines will bring you a story on the Northern Bald Ibis soon).

The Southern Bald Ibis core distribution range is located mainly in South Africa (from Limpopo, the northeastern Free State, Mpumalanga, to Kwazulu-Natal), although a significant part extends into Lesotho, and some occur in Swaziland. (Locally it’s known as Kalkoenibis in Afrikaans; Umcwangele  in Xhosa]; uNkondlo in Zulu; Lesuhla-ngeto, Mokhotlo in South Sotho.)

Southern Bald Ibis (©Richard Flack photo, www.theflacks.co.za). 
 Listen to the call (recorded by ©Scott Olmstead)

As already mentioned, the distinguishing feature in mature Southern Bald Ibis is the clearly visible crown—naked, bright red and domed. The rest of the head and upper neck, also naked, are whitish-beige. The long, downward curving bill is dull-red; the eyes are reddish. In direct sunlight, the dark plumage shines glossy green-blue, with a maroon-copper iridescence on the shoulder. The birds’ mass ranges from 1 to 1.3 kilograms; the length is between 70 and 80 centimeters, and the wingspan between 125 and 135 centimeters.

Southern Bald Ibis favor grasslands in high rainfall (>700mm p.a.) and high-altitude areas (>1200mm a.s.l), generally characterized by sour alpine vegetation. They forage on a suite of habitats including pastures, croplands, irrigated fields, and ploughed lands. Using their purpose-built beak, the birds probe the earth for, and feed on, insects, snails, worms, frogs, and even small birds (stomach contents of young chicks are reported to contain ca. 33% maize-stalk borers—hence the species benefits maize farmers).

The Southern Bald Ibis population is estimated at 6,592 individuals, with a declining trend. About half are breeding individuals, occupying ca. 245 nesting colonies (about a third of historical nesting sites are no longer utilized, due to the decline in breeding adults). The species is classified “Vulnerable” by IUCN, and listed in CITES App II.

Current recorded distribution of the Southern Bald Ibis from recorded data in the Second Southern African Bird Atlas Project (BirdLife SA)

Throughout its 257,000km2 breeding range, the major concern is loss of wetland habitat through degradation and fragmentation, intensive crop farming, afforestation, invasive flora encroachment, open cast mining and expansion of human settlements. Since 1990 available suitable habitat has declined by 14.3%; by the year 2050, climate change will lead to additional habitat shrinkage of ca. 34.4%.

Another significant threat is the illegal harvesting of eggs and young chicks for subsistence, traditional medicine, and ceremonial purposes. The disturbance caused by removal of eggs and chicks may lead to breeding sites being abandoned over time.

As a gregarious species, Southern Bald Ibis breed communally; colonies—two to 100 nests per site—are usually located on cliff ledges, in potholes on mountain slopes, along riverine gorges, or on a waterfall face. The breeding season lasts from July to December, with a peak in August and September (often correlating with burnt grassland availability).

Typical Southern Bald Ibis nest structure on a cliff ledge (BirdLife SA photo)

The clutch size varies between 1-3 eggs. The survival of multiple fledglings from the same nest is rare (apart from predation by white-necked raven and jackal buzzard, substantial losses are recorded during very wet years, when breeding colonies are flooded or washed out—the very reason why the birds choose cliff ledges for nesting). The South African fledgling survival rate (2004-2010) across 21 colonies was as low as 0.47.

Southern Bald Ibis Conservation Program

BirdLife SA initiated a long-term Southern Bald Ibis study for South Africa, which covered work on distribution range, numbers, survival rates of chicks/juveniles, breeding ecology and reproductive success, as well as trends of decline or expansion.

(Left): GSM tracking device on a juvenile Southern Bald Ibis (BirdLife SA photo)
Right: Initial tracking data captured from a juvenile Southern Bald Ibis chick tagged in January 2014 (BirdLife SA)

Eskom, the national electricity supplier, supported this conservation work through various initiatives, including a satellite tracking project. The latter served to determine the movement patterns of Southern Bald Ibis across seasons, where and how far these birds fly for foraging, and to what extent they return to natal sites to roost and/or nest. In 2014, two juvenile birds were fitted with satellite trackers. The tracking data shed light on their behavior, life history and fine scale habitat requirements. One tracking device failed after four months, whereas the second one provided consistent data for 30 months.

In 2016, BirdLife SA published the national Southern Bald Ibis action plan, identifying threats and constraints, including an action matrix categorized into research; monitoring; habitat conservation; and education and awareness.

Among the action plan’s objectives are various facets including:

Niche Modelling

This involves habitat suitability analyses for the entire range (available habitat under current land use practices in South Africa, Lesotho and Swaziland), as well as potential impact of climate change (including the greenhouse gas concentration trajectory). Known environmental constraints were factored in (elevation, slope, rainfall, eco region/biome, and fine scale land cover data).

The results highlight the available habitat to guide surveys for potential new breeding sites. An eastward shift of suitable habitat, and a contraction of available habitat along the western part of the current range was noted. The shift in suitable habitat also identified areas that may remain suitable under changing climatic conditions, and therefore, should be prioritized for conservation and stewardship initiatives.

Home Range, habitat use and foraging dynamics 

This investigation used cellular network tracking technology on the two juveniles mentioned earlier. Data generated through satellite trackers yield insights into the threats from habitat-use and foraging (i.e., foraging in pesticide-rich environments, possible human interactions, etc.). Home range size estimates and live movement data across seasons and habitats may also show the degree of migration—actual or potential—across international boundaries.

Monitoring of breeding colonies

BirdLife SA supporters and citizen scientists were involved in a largescale monitoring program between 2010 and 2015. Surveys of significant breeding colonies, and annual breeding assessments were made in cooperation with local Bird Clubs. Data for 224 breeding colonies across South Africa and Lesotho have now been collated, and are included in the Southern Bald Ibis database. These data are analyzed periodically to determine any changes in breeding success or distribution. For the areas which are still unmonitored (or unknown to the project), citizen scientists should relay information to BirdLife SA’s Carina Pienaar (she’s driving the project since 2004). Very important is also the recruitment of rural community members living near to breeding cliffs (this will rise awareness and buy-in at grass-root levels).

Artificial breeding 

After realizing that the waterfall home of a substantial Southern Bald Ibis breeding colony on the Ingula Pumped Storage Scheme (a pumped-storage power station on the Drakensberg escarpment in Kwazulu-Natal, South Africa) would be inundated with the construction of the Bedford Dam, a special relocation program was implemented. Eskom, recognizing the importance of this breeding colony, supported the creation of an artificial nesting ledge in 2010—a first for this species.

The artificial breeding site for Southern Bald Ibises on the Bedford Dam in Ingula Nature Reserve (BirdLife SA photos)

The original nesting site was flooded with the partial filling of the Bedford Reservoir in June 2015 (during the breeding season). Fortunately, the birds began use the artificial nest holes above the rock ledges. Since relocation, four successful fledglings have been recorded. Annual monitoring tests the effectiveness of this intervention and provides invaluable lessons regarding future development of artificial nesting ledges.

At the original breeding site (prior to flooding, between 2004 and 2010) breeding success low, with the national fledgling success being 88% higher. The 2008 to 2010 seasons saw breeding success rates of 0.25, 0.29 and 0.22 (lower survival rates were attributed to predation as well as mortalities associated with severe rainfall and nest flooding). The number of nests varied between seven and nine. The fledgling success rates in 2014 and 2015, however, stood at 0.33 and 0.35.

In 2019 up to 30 adults used the artificial site for roosting. A sudden increase in breeding activity was noted in 2020, with nine nests in total, and 13 chicks reaching fledging age. Three of the nests were located in the artificial potholes. This success is noteworthy for several reasons: after the previous four breeding seasons had consistently produced four chicks, it was thought that the site’s capacity had been reached. And although the potholes apparently provided valuable shelter from the elements for adults and fledglings, their design seemed to lack certain characteristics that would have made them suitable for nesting. Both assumptions were proved wrong. Nests in the potholes produced four of the 13 chicks that fledged.

In 2020, a research team lead by Dr Kyle Lloyd was able to ring 10 of the 13 juveniles. Two chicks received new GSM tracking devices, designed and fitted by Craig Nattrass. These juveniles will form part of a study of breeding success, the post-fledging spatial distribution and movement, habitat preference and use.

The BirdLife SA Southern Bald Ibis project ensures a new lease on life for this very special and iconic bird of the high grassland of Southern Africa.

Fritz Ganz, an accountant by profession, has a passion for of ethical fair chase hunting and conservation. Fritz freelances as author of stories on hunting and conservation related topics.  He’s a member of Custodians of Professional Hunting and Conservation-South Africa CPHC-SA, and lives in Derdepoort near Pretoria.  

Banner Image: Flying Southern Bald Ibis (Photo© by Richard Flack—www.theflacks.co.za)