Kate F Carstens

Endangered Wildlife Trust

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Kirsten Wimberger

Stellenbosch University

Johann C. Carstens

Endangered Wildlife Trust

Jessica Leaver

Endangered Wildlife Trust

R.M. Little

University of Cape Town

Peter G. Ryan

University of Cape Town

Reshma Kassanjee

University of Cape Town

Michael Cherry

Stellenbosch University

Clare Padfield

Endangered Wildlife Trust

Rowan O. Martin

University of Cape Town

R Stephen Boyes

University of Cape Town

Cooperative Institutions

University of Cape Town

Centre National de la Recherche Scientifique

John Wiley & Sons (United States)

University of Turku

Consejo Superior de Investigaciones Científicas

Google (United States)

Stellenbosch University

University of Helsinki

Ecological Society of America

University of Aberdeen

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Interactions between birds of prey and the Cape Parrot in the Eastern Cape.

Biodiversity Observations (2017)

Kate F Carstens Johann C. Carstens Kirsten Wimberger

Worldwide, parrots are most vulnerable to attack when congregating around feeding and drinking sites. Flocking is a way of minimising vulnerability to predation, but can increase predation risk when flocks are unusually large and conspicuous. The Cape Parrot Poicephalus robustus is endemic to South Africa and is listed as endangered, with an estimated 1250 mature individuals remaining in the wild. Predation attempts have been previously documented on individuals flying over natural forests. However, unusually large flocks gather during autumn and winter to feed on exotic Pecan Carya illinoinensis nuts growing in orchards in Eastern Cape, South Africa, and this may increase their risk to predation. Observations conducted on 13 mornings and seven afternoons during March-June 2017 revealed frequent flushing and chasing by raptors such as African Goshawk Accipiter tachiro and Black Sparrowhawk Accipiter melanoleucus. No predation events were witnessed, and carcasses found on the ground beneath pecan trees suggests either predation or individuals that succumbed to Psittaccine Beak and Feather Disease. Ongoing observations at pecan orchards during the pecan season would better evaluate predation levels, and other threats to this endangered species at these feeding sites away from Afromontane habitat.

Accipiter

Flock

Cape

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Monitoring an isolated population of Cape Parrots Poicephalus robustus in the Limpopo province, South Africa

Ostrich (2022)

Kate F Carstens Kirsten Wimberger Rowan O. Martin David Letsoalo Craig T. Symes

Cape Parrots Poicephalus robustus inhabit forest patches in South Africa with <1 800 individuals remain in the wild. A small, genetically isolated population occurs in the northern part of its range in the Limpopo province. There, annual counts indicated ∼100 remain, but count numbers fluctuate substantially between years creating uncertainty over population trends. To inform approaches to the monitoring of Cape Parrot populations in the Limpopo province, we investigated how local abundance counts varied within and across years at known parrot ‘hotspots’. Monthly counts were done at these sites during 2013–2015 and 2020–2021. We found large variability in counts both within and amongst years, although this differed between sites. Observations of behaviour suggest that a site close to overnight roosts was more reliable, whereas those close to food sources were more variable likely linked to fruit availability. The highest numbers were recorded at a pecan nut orchard away from the indigenous forest. To better understand population trends of this small, isolated population we recommend annual counts are complemented with a series of focused counts at pecan nut orchards, which are monitored with greater intensity during the fruiting season.

Cape

Orchard

10.2989/00306525.2022.2053599

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Nest boxes for Cape Parrots Poicephalus robustus in the Hogsback area, Eastern Cape, South Africa

Figshare (2018)

Kirsten Wimberger Kate F Carstens Johann C. Carstens R Stephen Boyes

Breeding propensity of tree-cavity nesting bird species are often limited by a shortage of natural nesting sites. Artificial nests can be used to provide alternative nest sites. Cape Parrots Poicephalus robustus are nationally endangered and nest in existing tree-cavities in high-altitude fragmented Afromontane forests in South Africa, assumed to be in short supply due to historic and current logging practices. To increase nest site availability, 179 wooden bird boxes and 28 bee boxes (to ‘pull’ bees) were erected during 2011–2012 in Hogsback, Eastern Cape. In 2016, no bird boxes were occupied by Cape Parrots. A total of 43% were used by other species, 51% were unused and 6% could not be inspected due to tree instability and inaccessibility. Two bird boxes were inspected by two pairs of Cape Parrots, but were never occupied. Occupancy of boxes by birds was not associated with nest, tree or habitat characteristics. However, occupancy of boxes by bees was associated with habitat type and tree species. Future conservation efforts will include locating natural Cape Parrot nesting sites and reforestation efforts to ensure the long-term availability of natural nesting sites.

Cape

Nest box

10.6084/m9.figshare.5732304

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Breeding and dispersal implications for the conservation of the Southern Ground Hornbill Bucorvus leadbeateri

Kate F Carstens

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Cape Parrot Poicephalus robustus diet in a nutshell: use of indigenous and exotic plants in the Eastern Cape province, South Africa

Ostrich (2023)

Kirsten Wimberger Kate F Carstens Johann C. Carstens Francis R Martens Fanie Rautenbach

The success of conservation action for a threatened species can be improved by knowledge of its feeding and breeding requirements. The Cape Parrot Poicephalus robustus is a threatened endemic restricted to patches of mistbelt forest in South Africa. Cape Parrots are considered dietary specialists, preferring the kernels of yellowwood Podocarpus/Afrocarpus species, and consuming other species when these are not available. We investigated the diet composition of Cape Parrots in the Amathole region of the Eastern Cape province through targeted and opportunistic observations from 2016 to 2021. We monitored the availability of indigenous and exotic forest fruit over this timeframe and determined whether between-season and within-season differences were significant. We also monitored Cape Parrot presence and diet, weekly, at a pecan tree orchard and collected pecan nuts for compositional analysis. Additionally, we investigated whether Cape Parrots tracked this exotic feeding resource relative to local indigenous fruit abundance and changes in pecan nut composition. Cape Parrots were observed feeding on 36 tree species during this study, of which 61% were exotic. We recorded 24 new tree species (mostly exotics) not previously recorded as eaten by this parrot species. However, most feeding records were of parrots eating indigenous rather than exotic species, excluding the targeted observations of them eating at pecan orchards. Cape Parrots fed on pecans in each season despite the relatively high availability of indigenous forest fruits. Although not significant, Cape Parrots appeared to track changes in pecan nut composition during each season, gathering in the largest numbers when fat levels in the pecans were highest. Cape Parrots appear to be adapting to human-modified habitat based on the observations of annual visits to exotic pecan orchards and the high number of exotic species in their diet. The impact of exotic feeding resources on their health remains to be determined.

Cape

Dry season

Orchard

10.2989/00306525.2022.2164805

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Population trends of the Cape Parrot Poicephalus robustus in the Amatholes, Eastern Cape: trialling ground-based flock photography for demographic and health assessment

Ostrich (2024)

Clare Padfield Kate F Carstens Johann C. Carstens Francis R Martens Kirsten Wimberger

AbstractGlobally, 60% of species in the order Psittaciformes are experiencing population declines. Understanding demographic and health trends in populations is vital for the prioritisation of limited conservation resources. The Cape Parrot Poicephalus robustus is a South African endemic forest species that is endangered by habitat degradation and Psittacine Beak and Feather Disease (PBFD). In the Amathole region of the Eastern Cape province, Cape Parrots gather in large numbers every autumn to feed at a particular orchard of Pecan trees Carya illinoinensis. This annual event is an opportunity for researchers to assess trends in a population that does not otherwise typically form large flocks. We used a novel, non-invasive method of flock photography analysis between 2017 and 2022 to assess the demographics and PBFD symptoms of the population. A mean of 439 ± SD 127 Cape Parrots visited the orchard on the peak day each year, with 1.2 males per female and 3 adults per juvenile overall. Proportions of juveniles fluctuated between extremes of 70% in 2019 and < 4% in 2020. PBFD symptoms increased markedly in the food-scarce year of 2019, with a gradual recovery seen in the years following. Roosting numbers were also tracked monthly from 2018 to 2022 to indicate local population fluctuations in the study area around Hogsback. An average of 112 ± SD 31 Cape Parrots roosted there, with roost counts notably higher from January to June, bolstered by newly-fledged juveniles prior to their dispersal. This study demonstrates the use of flock photographs as an effective, non-invasive tool to assess the demographics and health of an avian population.À l'échelle mondiale, 60 % des espèces de l'ordre des Psittaciformes subissent des déclins de leurs populations. Il est essentiel de comprendre les tendances démographiques et sanitaires des populations pour établir des priorités parmi les ressources de conservation limitées. Le Perroquet robuste Poicephalus robustus est une espèce forestière endémique d'Afrique du Sud qui est menacée par la dégradation de l'habitat et la maladie du bec et des plumes (PBFD: Psittacine Beak and Feather Disease). Dans la région d'Amathole, dans la province du Eastern Cape, les Perroquets robustes se rassemblent en grand nombre chaque automne pour se nourrir dans un verger particulier de pacaniers Carya illinoinensis. Cet événement annuel est l'occasion pour les chercheurs d'évaluer les tendances d'une population qui ne forme généralement pas de grands rassemblements. Nous avons utilisé une nouvelle méthode non invasive d'analyse de photographies de volées entre 2017 et 2022 pour évaluer la démographie et les symptômes de la PBFD de la population. En moyenne, 439 ± SD 127 Perroquets robustes ont visité le verger le jour du pic de comptage de chaque année, avec 1,2 mâles par femelle et 3 adultes par juvénile. Les proportions de juvéniles ont fluctué entre des extrêmes de 70% en 2019 et < 4% en 2020. Les symptômes du PBFD ont augmenté de façon marquée en 2019, année de pénurie alimentaire, avec un rétablissement progressif au cours des années suivantes. Le nombre de dortoirs a également été suivi mensuellement de 2018 à 2022 pour estimer les fluctuations de la population locale dans la zone d'étude autour de Hogsback. En moyenne, 112 ± SD 31 perroquets du Cap ont utilisé les dortoirs, avec des comptages notablement plus élevés de janvier à juin, coïncidant avec l'arrivé de juvéniles récemment sortis du nid. Cette étude démontre que l'utilisation de photographies d'oiseaux en vol peut être un outil non invasif efficace pour évaluer la démographie et la santé des populations.Keywords: flock photographypopulation demographypopulation health

Cape

Flock

10.2989/00306525.2024.2410496

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The effects of weather, group size and type of nest on the timing of egg-laying in the Southern Ground-hornbill Bucorvus leadbeateri

Journal of Ornithology (2019)

Kate F Carstens Reshma Kassanjee R.M. Little Peter G. Ryan Phillip A. R. Hockey

Fledge

Avian clutch size

Laying

10.1007/s10336-019-01654-x

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Citations (3)

A new action plan developed for the Cape parrot and its habitat

Oryx (2020)

Jessica Leaver Kate F Carstens Kirsten Wimberger Clare Padfield Rowan O. Martin

An abstract is not available for this content. As you have access to this content, full HTML content is provided on this page. A PDF of this content is also available in through the ‘Save PDF’ action button.

Cape

Action plan

Content (measure theory)

10.1017/s0030605320000642

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Breeding success and population growth of Southern Ground Hornbills Bucorvus leadbeateri in an area supplemented with nest-boxes

Bird Conservation International (2019)

Kate F Carstens Reshma Kassanjee R.M. Little Peter G. Ryan Phil Hockey

Summary The provision of artificial nests can improve the conservation status of threatened bird species that are limited by nest-site availability. The shortage of natural cavity nesting sites is one factor limiting the population growth of the Southern Ground Hornbill Bucorvus leadbeateri . In an 1,800 km 2 study area in north-eastern South Africa, 31 wooden nest-boxes were installed during 2002–2015. We investigated the relationships between nests, as well as environmental and social factors, with breeding. Generalised linear mixed models were fitted to the observational data and identified positive relationships between breeding attempts and each of home range size and the previous year’s rainfall; as well as positive relationships between breeding success (amongst the groups that attempt breeding) and each of earlier breeding, nest height and thickness of the nest cavity wall. The provision of nest-boxes increased the number of breeding groups and although breeding success also increased initially, it later declined as the density of breeding groups increased above 20 groups. Although nest-boxes alone did not increase overall breeding success, they are an effective conservation tool to enhance the population of Southern Ground Hornbills if spaced optimally, to enhance reproductive output in areas where suitable nest-sites are scarce or lacking.

Economic shortage

Limiting

Nest box

10.1017/s0959270919000108

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Citations (16)

Nest boxes for Cape Parrots Poicephalus robustus in the Hogsback area, Eastern Cape, South Africa

Ostrich (2017)

Kirsten Wimberger Kate F Carstens Johann C. Carstens R Stephen Boyes

Breeding propensity of tree-cavity nesting bird species are often limited by a shortage of natural nesting sites. Artificial nests can be used to provide alternative nest sites. Cape Parrots Poicephalus robustus are nationally endangered and nest in existing tree-cavities in high-altitude fragmented Afromontane forests in South Africa, assumed to be in short supply due to historic and current logging practices. To increase nest site availability, 179 wooden bird boxes and 28 bee boxes (to ‘pull’ bees) were erected during 2011–2012 in Hogsback, Eastern Cape. In 2016, no bird boxes were occupied by Cape Parrots. A total of 43% were used by other species, 51% were unused and 6% could not be inspected due to tree instability and inaccessibility. Two bird boxes were inspected by two pairs of Cape Parrots, but were never occupied. Occupancy of boxes by birds was not associated with nest, tree or habitat characteristics. However, occupancy of boxes by bees was associated with habitat type and tree species. Future conservation efforts will include locating natural Cape Parrot nesting sites and reforestation efforts to ensure the long-term availability of natural nesting sites.

Cape

Occupancy

Nest box

10.2989/00306525.2017.1405094

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Citations (3)