Africa's Tale Of Two Bald Ibis Families

The United Nations Environment Program (UNEP) has launched the World Migratory Birds Day campaign to create global awareness about the importance of bird conservation.

Eswatini is home to the southern bald ibis (Geronticus calvus), which is found as well in some parts of South Africa and Lesotho.

The southern bald ibis is endemic and restricted to the southeastern Africa region, roosting in open montane grasslands and preferring to breed on steep cliffs with dams below.

The Eswatini National Trust Commission's senior ecologist, Sandile Gumedze, said the kingdom's gregarious bird favors selected montane grasslands with high rainfall and less tree species density, and their main colony is the Mahamba Gorge in south of the country.

"They don't like places with tree species," he said. "The advantage they have in grasslands is the ability to forage on a variety of insects easily, especially on burnt grasslands. They feed on crabs as well, as they move along streams and riverbanks."

"During their breeding and nesting season between July and December, they are visible and active in their flight patterns. They perch on steep cliff areas to avoid disturbance and breed where human reach is almost impossible," said Gumedze.

On the other hand, their counterparts, the northern bald ibis (Geronticus eremita), have a desert orientation. They also breed in colonies on cliff ledges in semi-desert regions and forage in open dry habitats.

According to e-bird, northern bald ibis are historically bred in central and southern Europe.

They are also critically endangered, with most remaining birds in Morocco. Migratory eastern populations in Syria and Turkiye are all but extinct.

Climate change and threats facing bald ibis

Seth Maphalala, Transfrontier Conservation Area manager at Eswatini's National Trust Commission, said they noted a new trend in terms of the visibility of the bird within its ecological range.

"Now they are visible even when it is not their breeding and nesting season. We have established two new breeding and nesting sites as well at Nkoyoyo and Mhlume," said Maphalala.

"I am not sure why these developments (have occurred) concerning the behavior of the bird, but the changes in climate conditions might be the factor."

Gumedze echoed Maphalala's sentiments and highlighted the negative prospects that climate change would have on the bird species' ranges.

"The threat of trees encroachment to montane grasslands is most likely to happen. Such alteration of grasslands ecosystems will impact negatively the southern bald ibis populations which favor grasslands.

"We are already observing a decrease in their population," said Gumedze. "We no longer have those high numbers we used to have. Climate change and irresponsible human behavior might be the cause."

Gumedze further criticized the small-paced progress by countries in committing to the Paris Agreement, stating that stopping global warming was a solution to save the bird populations.

Moreover, the European Rewilding Network stated unapologetically that the northern bald ibis is also one of the most endangered migratory bird species worldwide and marked as critically endangered on the International Union for Conservation of Nature's Red List of threatened species.

Because of low global populations, the reintroduction of the northern bald ibis is one of Europe's largest species conservation projects.

Different migration patterns

Although the northern bald ibis is clearly classified as a migratory species, their closest cousins the southern bald ibis are a different case as experts acknowledge their migration is strictly confined within their ecological range.

Professor Ara Monadjem, a lecturer in the department of biological sciences at the University of Eswatini, said owing to the fact that the species is endemic to South Africa, Lesotho and Eswatini and does not occur outside this region, any migration is strictly within this region.

"In Eswatini, part of the population is migratory, presumably moving to South Africa in mid-summer and returning in mid-winter to start breeding, while other populations are sedentary and remain all year round," Monadjem said.

Gumedze again noted the long-held misconception about the migratory pattern of the bird.

"All along, we were of the understanding that the southern bald ibis migrates to North Africa. Our problem was that we confused it with the northern bald ibis.

"Now we see they stick within their ecological range. Upon close inspection of their habitat sites, we could see that their nests were long abandoned, although their minimal numbers are visible way past the breeding season. That's what makes us sit between migration and non-migrant," said Gumedze.

However, Maphalala revealed that in certain habitats like Mantenga Falls, the southern bald ibis no longer disappears. But in other breeding sites, they migrate probably to their ecological range in South Africa. -