Feeding ecology of the Southern Bald Ibis, <i>Geronticus calvus,</i> in the Free State, South Africa

Kopij, Grzegorz

doi:10.2989/00306520109485316

Cited by 9 publications

(9 citation statements)

References 2 publications

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“…For the period 1988–1998 Bohm (1999b) reported that 76.4% of eggs hatched in zoos resulted in fledged young which would convert to an overall breeding success of more than two young per pair. Three studies of the closely related Southern Bald Ibis from different areas show productivity figures of between 0.29 and 0.84 chicks/pair (Allan 1985, Manry 1985, Kopij 1998), again lower than the average in the present study.…”

Section: Discussioncontrasting

confidence: 89%

“…The only other species in the genus Geronticus , the Southern Bald Ibis Geronticus calvus , found in South Africa and Lesotho, is also threatened (classed as ‘vulnerable’). The Southern Bald Ibis often nests in smaller colonies and appears to be more adept at exploiting cultivated habitats (Kopij 2001). It also has a much less synchronized breeding season than G. eremita , laying eggs over a 3‐month period (Kopij 1998), thus allowing further adaptability.…”

Section: Discussionmentioning

confidence: 99%

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The status and recent breeding performance of the critically endangered Northern Bald Ibis Geronticus eremita population on the Atlantic coast of Morocco

Bowden

Aghnaj

Smith

et al. 2003

Ibis

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The main wild population of the Northern Bald Ibis Geronticus eremita breeds on the Atlantic coast of Morocco in the Agadir region. This paper describes the numbers of breeding pairs over the last two decades, the recent breeding performance, the causes of egg and chick losses and their conservation implications. Since 1980 there has been no overall decline in numbers with, over the last 5 years, 59–74 pairs breeding and a peak prebreeding population of around 220 birds. In contrast with the now extinct Northern Bald Ibis populations in Turkey and elsewhere in Morocco, the birds are present in the Agadir region throughout the year and do not appear to migrate from the area outside the breeding season. Breeding performance is highly variable from one year to the next but does not appear to be related to rainfall in the vicinity of the colonies as has been reported elsewhere. It is suggested that coastal fogs in this region may buffer the adverse impacts of low rainfall and may in part account for the year‐round residency of the birds. The main causes of breeding failures have been loss of eggs to predators and, most importantly, poor chick survival as a result of starvation and predation. Conservation action to date has focused on reducing the negative influences on breeding success but it is recognized that for such a long‐lived bird adult survival is also likely to be an important limiting factor on the population size.

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Section: Discussioncontrasting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

The status and recent breeding performance of the critically endangered Northern Bald Ibis Geronticus eremita population on the Atlantic coast of Morocco

Bowden

Aghnaj

Smith

et al. 2003

Ibis

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“…It is not clear why the birds did not use cut hayfields that winter but it was possibly because of elevated prey levels in the pasture linked to the delayed termination of the long rainy season in that year. Unlike Wattled Ibis, Northern Bald Ibis avoided tall grass (Bowden et al 2003, Kopij 2001) only using hayfields once they were cut. As on the breeding grounds (Serra et al 2008) and unlike on migration (Serra 2010), ibises avoided cultivated fields for foraging at IWR, even abandoned fields, despite these being used by other birds such as Wattled Ibis and Common Crane Grus grus .…”

Section: Discussionmentioning

confidence: 99%

An assessment of ecological conditions and threats at the Ethiopian wintering site of the last known eastern colony of Critically Endangered Northern Bald IbisGeronticus eremita

Serra

Bruschini

Peške³

et al. 2013

Bird Conservation International

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The long-range, migratory eastern relict population of Northern Bald Ibis Geronticus eremita has been steadily declining since the time of discovery in 2002, despite the protection programme in place at the breeding grounds in Syria. Assessing the ecological conditions and threats along the migration route and at the wintering site, both discovered in 2006, has become a priority for this "Critically Endangered" species. Adult ibises spent the winter at the same site on the central Ethiopian highland plateau, from August until mid-February during five consecutive winters (2006)(2007)(2008)(2009)(2010)(2011). The wintering site was surveyed during four field visits and assessed through a spatial analysis of 1,067 satellite locations. The site is in an agro-pastoral landscape, inhabited by a settled community of people living in relatively poor and isolated conditions. Home range analysis based on kernel distributions showed that the bald ibises used a core range area of 9.1-19.0 km² (confirmed by direct visual observations in the field) and an extended range area of 61.0-126.1 km². These figures are c.20 and 60 times smaller, respectively, than those calculated for the breeding site in Syria. Eighty-one percent of the core area in Ethiopia was used in all five years confirming the birds' fidelity to this wintering site. Ibises preferred to forage in wet or dry pastures and in recently cut hayfields, and avoided tall grass, uncut hayfields and cultivation. Despite dependence on human-created habitats, human disturbance observed in the field was minimal. The main short-term threat for the ibises was judged to be the potential raising of attention on the part of the local community specifically towards these few individual ibises. In the medium term, the main threat comes from the conversion of pastures into crops and the potential use of fertilisers and pesticides.

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“…Repeating the analysis using numbers of nests and multiple monitoring events, we demonstrate no signi cant decreases in reproductive output overall: while the exact colonies used in the previous analysis are unknown, the database we use contains at least some of the colonies. Local habitat transformation may result in a redistribution of adult birds rather than re ect population declines, especially if the transformation is to grain based agriculture, where the species is recorded foraging (Kopij 2001). We note that nesting does not occur at all colonies in all years.…”

Section: Discussionmentioning

confidence: 99%

“…We postulate that the association of NDVI to 'extinction' risk could possibly be related to the foraging and habitat preferences of the species. Southern Bald Ibis are noted to forage exclusively in open habitats with short vegetation, avoiding woody and tall grass habitats in which foraging e ciency decreases drastically (Kopij 2001). Preferred foraging habitats primarily include habitats with low vegetative biomass such as recently burnt grass, short (grazed) grass, reaped maize, ploughed maize and short lucerne elds (Kopij 2001).…”

Section: Discussionmentioning

confidence: 99%

An improved conservation status of Southern Bald Ibis Geronticus calvus as informed by a diversity of citizen science projects suggests positive impacts of conservation attention

Lee¹,

Pienaar²,

Chetty

et al. 2023

Preprint

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The Southern Bald Ibis is endemic to South Africa, Lesotho and Eswatini, occurring across high and mid- altitude mesic grasslands and has been of conservation concern in the seventies, resulting in a range of monitoring, research and conservation actions. We examine a range of data sources to determine the conservation status of this species, employing a variety of statistical and analysis pathways. We compare trends in reporting rates from Southern African Bird Atlas Projects (SABAP), examine trends in numbers of nests reported through colony monitoring, and explore contributions made to the ‘Threatened species cause’ from the BirdLasser mobile app. Using the BirdLasser data, we find the species is widely reported across the range outside of sites with known colonies and roosts, suggesting a large proportion of the population is not available for counting during the breeding season. Using insights from the SABAP data and occupancy modelling, combined with group counts from BirdLasser data, we suggest the population is likely > 10 000 individuals. None of the trend analysis statistics we used revealed a decrease in population size for the period 1987–2021. We note that certain colonies are still being abandoned, but this is now at a lower rate (< 10% of colonies). After dramatic declines from the early part of the last century, this suggests the declines are now being curtailed, and there is some evidence the species may be recolonizing lost range. However, we note that this species is being negatively impacted by loss of grasslands to alien vegetation, and will likely be negatively impacted by climate change and other developments. While it is difficult to infer causality with conservation attention, the reversal in the fortunes of the species is encouraging for those involved in the long conservation journey of this species. Continued monitoring of this charismatic species is required in addition to ongoing habitat management to ensure declines are conclusively reversed.

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Feeding ecology of the Southern Bald Ibis, Geronticus calvus, in the Free State, South Africa

Cited by 9 publications

References 2 publications

The status and recent breeding performance of the critically endangered Northern Bald Ibis Geronticus eremita population on the Atlantic coast of Morocco

The status and recent breeding performance of the critically endangered Northern Bald Ibis Geronticus eremita population on the Atlantic coast of Morocco

An assessment of ecological conditions and threats at the Ethiopian wintering site of the last known eastern colony of Critically Endangered Northern Bald IbisGeronticus eremita

An improved conservation status of Southern Bald Ibis Geronticus calvus as informed by a diversity of citizen science projects suggests positive impacts of conservation attention

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