Craig Symes

• PhD
• Professor (Associate) at University of the Witwatersrand

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...

Aloe reitzii var. reitzii is a summer-flowering (February–March) succulent, endemic to a restricted range within the heavily transformed grasslands of eastern South Africa. Floral structure and nectar properties suggest bird-pollination. This study investigated the temporal visitation events of birds to this aloe. Extensive camera observations duri...

Floral nectar is an important attractant and reward for visitors, and is often produced in synchrony with peak activity of pollinators. Aloe peglerae flowers in winter, and previous studies have shown that it is pollinated primarily by diurnal generalist birds, with small mammals making additional contributions to pollination at night. Nectar produ...

Plant–animal interactions are key to sustaining whole communities and ecosystem function. However, their complexity may limit our understanding of the underlying mechanisms and the species involved. The ecological effects of epizoochory remain little known compared to other seed dispersal mechanisms given the few vectors identified. In addition, ep...

Decreases in suitable habitat due to loss and fragmentation on the African nonbreeding grounds are believed to be a driver of the declines in Palaearctic migrants. However, the effects of habitat loss and fragmentation on individual migrants have rarely been investigated. The European Honey-buzzard Pernis apivorus, a migratory forest specialist, di...

Between 2012 and 2018 a total of 2094 individual birds representing 265 species (168 passeri-formes and 97 non-passeriformes), 70 families (32 passeriformes and 38 non-passeriformes) and 21 orders were sampled for louse-flies and other ectoparasites in different locations in all nine provinces of South Africa. A total of 153 louse-flies of six gene...

Sex and age segregation on the non-breeding grounds is common in raptor species. We studied the European Honey Buzzard (Pernis apivorus) on its southern African non-breeding grounds to examine changes in sex and age ratios over a period of recent population expansion (2002–2017). Photographs from multiple open sources were analysed. The adult popul...

Hybridisation is the interbreeding of genetically distinct groups that can lead to introgression – an exchange of genetic material between species. Hybridisation is of conservation concern when an alien invasive species is involved, as it can lead to a loss of local genetic adaptations and genetic diversity. Hybridisation is a significant threat fo...

Anthropogenic activities have resulted in the dispersal of many species beyond their natural range and there is ongoing concern over their impacts on native ecosystems. However, these interactions are hard to disentangle from the effect of human-driven habitat alterations. Psittacula krameri (Rose-ringed Parakeet) is a recent coloniser in the heavi...

Aim Long‐distance Palaearctic migrant birds are declining at a faster rate than short‐distance migrant or resident species. This is often attributed to changes on their non‐breeding grounds and along their migratory routes. The European honey buzzard (Pernis apivorus) is a scarce migrant in southern Africa that is declining globally. This study ass...

The movements of birds and small mammals may be affected by spatial and temporal variation in resource availability. For the genus Aloe, bird abundance and diversity increase in response to increases in nectar availability during flowering. Aloe peglerae Schönland, endemic to the Magaliesberg Mountain Range, South Africa, is primarily pollinated by...

The Common Starling Sturnus vulgaris has progressively expanded its range in South Africa since its introduction into Cape Town in the late 19th century. In the past few decades it has extended this range into Gauteng province. Using data from the Southern African Bird Atlas Project 2, this paper examines the spread and relative abundance changes f...

Stable isotope analyses are a powerful tool in understanding diets, defining trophic networks, inferring geographical origins of animals and in forensic tracing of the origins of deceased humans or illegally traded animal and plant material. African grey parrots Psittacus erithacus are one of the most traded animal species in the world, and the ori...

Observations of relatively large frugivorous birds, e.g. Purple-crested Turaco, feeding on cycad fruit are provided and contextualized in the important role they play in seed dispersal.

South Africa has a high diversity of birds (~850 species) but few have been studied for parasites. This study presents data on the distribution of chewing lice for passeriform birds in South Africa. Field trips were conducted across the country during 2012-2018. Birds were caught using mist nets and checked for ectoparasites using visual examinatio...

Background: Aloe reitzii var. reitzii is a succulent with a restricted distribution in the montane grassland of eastern South Africa. It is a summer (late January–March) flowering succulent that grows on rocky outcrops at 1000 m–1600 m, and the conspicuous inflorescences suggest a pollination system focused towards birds. Objectives: To understand...

Xylitol is an alternative sweetener to sucrose, glucose and fructose, and is available under a number of brands in South Africa. Carbon stable isotope values (δ13C) of a selection of commercially available xylitol products (n=28) were analysed and compared with sugar samples (n=29). Sugarcane (C4) and beet sugar (C3) derived sugar samples aligned w...

Diet–tissue isotopic relationships established under controlled conditions are informative for determining the dietary sources and geographic provenance of organisms. We analysed δ¹³C, δ¹⁵N, and non-exchangeable δ²H values of captive African grey parrot Psittacus erithacus feathers grown on a fixed mixed-diet and borehole water. Diet–feather Δ¹³C a...

Avian communities in urban environments of continental Africa are generally poorly understood. Gauteng, one of South Africa’s nine provinces and the second largest mega-urban region in sub-Saharan Africa, includes the conurbation of Johannesburg and Pretoria. Rapid urbanisation in the province began in the 1880s after the discovery of gold and is,...

We studied the spatial and temporal dietary patterns of the Amur Falcon (Falco amurensis), a nonbreeding Palearctic migrant to South Africa, by collecting regurgitated pellets at two large colonial roost sites, i.e., Middelburg and Newcastle, over 11 equal sampling periods during December 2012 to March 2013. We dried the pellets to constant mass an...

The pollination syndrome of the genus Aloe, with gaudy inflorescences and orange–red flowers, suggests bird pollination. However, the diversity of flowering phenologies and structures suggests that generalizations within the group are currently uninformative because few studies have addressed the role of multiple pollinator guilds, especially mamma...

A project documenting the diversity of endo- and ecto-parasites of South Africa’s avifauna is ongoing since late 2011. Live birds have been sampled for ectoparasites during field trips to different parts of the country while accompanying ringers. For endoparasites, road kills were collected and sampled. Results for Limpopo province are presented he...

Long-distance dispersal events and their derivable increases of genetic diversity have been highlighted as important ecological and evolutionary determinants that improve performances of range-expanding species. In the context of global environmental change, specific dispersal strategies have to be understood and foreseen if we like to prevent gene...

The diet of Temminck's ground pangolin Smutsia temminckii (hereafter, pangolin) has thus far been studied only in mesic savannahs. We provide arid-zone dietary data for this species based on direct observations, and compare these to available prey species assemblages. We also report stable carbon and nitrogen isotope enrichment values for liver and...

Worldwide, there is concern about the increased prevalence of infectious diseases and their effects on biodiversity. Increasing changes in the environment, particularly changes in climatic conditions as a consequence of anthropogenic-induced climate change, are some of the factors driving this increased disease prevalence. Vertebrate taxa that appe...

Succulent aloes of savanna and grassland ecosystems have adaptations to fire but favourable local-scale microhabitat conditions can further support plant growth, reproduction, and survival. However, due to the heterogeneity in habitat structure, it may be unclear what type of microhabitat predictors are important for aloe conservation, and hence mi...

Parrot populations in Africa and Madagascar are declining and the need for conservation actions to address threats is increasingly recognised. Effective conservation requires a robust knowledge base on which decisions over appropriate actions can be made, yet at present there is no current and readily accessible synthesis of the status of populatio...

Diet of co-occurring Barn Owl and Spotted Eagle Owl has been studied by means of pellet contents analysis in urban and rural environments in the Highveld of South Africa. In urban environment, diet of both owl species was dominated by murid rodents (mainly Otomys, Mastomys and Rhabdomys). In rural environment, Barn Owl diet was also dominated by mu...

A total of 655 individuals of 110 passerine species belonging to 28 families were examined for chewing lice in South Africa. A total of 80 (12 %) birds of 33 species were parasitized with amblyceran chewing lice (Phthiraptera: Amblycera) belonging to three genera: Menacanthus, Myrsidea and Ricinus. In this paper we report the occurrence of 11 speci...

Parrots (families Psittacidae and Cacatuidae) are one of the most threatened taxa of birds, with a combination of threats to wild populations, including capture for the cage bird market, habitat modification and destruction, persecution, disease, and threats from introduced species. As a result of the group's popularity as a cage bird, and the tran...

Our study reports on contrasts in prey items from African Crowned Eagle Stephanoaetus coronatus nesting in forest (n = 1) and savanna (n = 2) biomes in KwaZulu-Natal, South Africa. At least 12 taxa were identified at a forest nest, of which 92.1% were neonate/juvenile. Bovids and procaviids represented 73.7% and 19.6% of the diet, respectively, whi...

Data from two long-term citizen science projects were used to examine the status and ecology of a Red List species, the Secretarybird Sagittarius serpentarius (Vulnerable), in South Africa. The first phase of the Southern African Bird Atlas Project operated from 1987 until 1992, and the second phase began in 2007. The Coordinated Avifaunal Roadcoun...

Diet of co-occurring Barn Owl and Spotted Eagle Owl has been studied by means of pellet contents analysis in urban and rural environments in the Highveld of South Africa. In urban environment, diet of both owl species was dominated by murid rodents (mainly Otomys, Mastomys and Rhabdomys). In rural environment , Barn Owl diet was also dominated by m...

The White-winged Flufftail Sarothrura ayresi is a poorly known, globally threatened species that only occurs with any regularity in South Africa and Ethiopia. A survey of 13 high-altitude South African wetlands, including nine important sites for the flufftail, was undertaken in the summer of 2013-14 to attempt to assess the flufftail’s current sta...

Most Cape Parrot, Poicephalus robustus, nests have been recorded in snags (standing dead trees) making monitoring of nest contents and nest activities difficult and dangerous. Here the breeding activity of a Cape Parrot pair in the cavity of a live Henkell's Yellowwood (Podocarpus henkellii) is presented. Four eggs were laid in early-August and thr...

The diets of Falco amurensis and F. naumanni were investigated by analysing the respective stomach contents of 64 and 22 individuals killed during a severe thunderstorm in December 2004. Interpretations of diet were made by considering (1) biomass of dietary items and (2) presence/absence of dietary items in the stomachs analysed. A single beetle (...

Spatial and temporal patterns of disturbance and the subsequent heterogeneity are critical in maintaining biodiversity within grassland ecosystems. Grassland birds have evolved within this ‘shifting mosaic’ to become reliant on specific habitat characteristics maintained under varying levels of both natural and anthropogenic disturbance. Unfortunat...

Spatial and temporal patterns of disturbance and the subsequent heterogeneity are critical in maintaining biodiversity within grassland ecosystems. Grassland birds have evolved within this ‘shifting mosaic’ to become reliant on specific habitat characteristics maintained under varying levels of both natural and anthropogenic disturbance. Unfortunat...

It is often hypothesized that two species competing for the same resource cannot stably coexist unless they partition their resources in space and time. More recently stable isotope analyses have complemented traditional, observation-based niche research by conceptualizing many of the characteristics of communities, for example, trophic niche width...

South Africa has nearly 850 bird species and South Africa’s northernmost province, the Limpopo province, boasts more than 600 recorded bird species (approximately 420 breeding resident spp). Despite previous reports of a few species of lice and ticks from birds of Limpopo Province there is generally insufficient knowledge of etoparasites of birds i...

It is well recognised that highly fragmented and/or declining plant populations may be less attractive to pollinators. As a consequence, this can lead to a decline in any component of individual or overall fitness within a population. The Allee effect is particularly common in rare or endangered plant species. The aim of this study was to investiga...

Summary. Schotia brachypetala flowers in spring and early summer and produces copious nectar that attracts numerous specialist and opportunistic nectar-feeding bird species. Twenty-eight bird species were observed feeding on the nectar of two flowering trees, one in Limpopo province and another in Gauteng province, both in South Africa, during Sept...

Opportunistic bird pollination has become more evident in studies that confirm distinct differences in floral adaptations that attract opportunistic, rather than specialist, bird pollinators. Pollination syndrome studies investigating the effectiveness of different pollinator guilds on reproduction seldom do so by measuring seed viability. We studi...

Anthropogenic land transformation processes in the vicinity of the Walter Sisulu National Botanical Garden, Johannesburg, South Africa, are a significant threat to natural vegetation and biodiversity. Breeding and feeding records of a Verreauxs' eagle (Aquila verreauxii),pair in the garden were analysed in relation to changes in the local environme...

Aloe marlothii flowers during dry winter months (July–September) and produces large numbers of wind dispersed seeds. Fire disturbance in a population of several thousand A. marlothii plants at Suikerbosrand Nature Reserve, Gauteng, permitted a series of seed dispersal experiments to be conducted. Germination trials indicated that seedling emergence...

No abstract in paper.

We believe that we amply demonstrated the importance of Amur Falcons towards agriculture and ecology in South Africa and Southern Africa. Based on our calculations and observations, it may even be considered a keystone species. Any significant reduction in falcon numbers may have significant consequences and their conservation and maintenance of nu...

Inferred hybrid Chorister Robin-Chat Cossypha dichroa and Red-capped Robin-Chat C. natalensis have previously only been recorded from the Eastern Cape province, South Africa. We extend the occurrence of inferred hybrids with ringed and photographed examples from KwaZulu-Natal and Limpopo provinces. Sympatry at a fine scale was investigated at Verno...

We measured δ13C and δ15N isotope signatures in flight feathers of a White-bellied Sunbird to assess the value of using stable isotopes of feathers in avian dietary studies. Significant variation in δ13C and δ15N isotope values of flight feathers (range = 3.1%o and 2.7%o, respectively) indicated that the source of carbon (i.e. C3 or CAM) and trophi...

Abstract The diet of the harvester termite Hodotermes mossambicus was investigated at two sites with distinct dietary components: C4 grasses (13C isotope values, −13.8‰ to −14.0‰) and C3 plants (13C isotope values, −25.6‰ to −27.1‰). By comparing observations of food items carried into the colony by the termites and carbon isotope ratios of whole...

The winter-flowering succulent Aloe marlothii provides nectar for many opportunistic avian nectarivores in southern African savannas. We assessed the importance of A. marlothii nectar sugar for opportunistic nectarivores by analysing temporal changes in stable carbon isotope ratios (δ13C) in the tissues of birds in Suikerbosrand Nature Reserve, Sou...

Turdus smithi, formerly a subspecies of T. olivaceus, has been elevated to species status, resulting in a void in our knowledge on this species. Although both T. smithi and T. olivaceus are common garden birds throughout their ranges, most studies to date have focused on T. olivaceus. These studies found that T. o. olivaceus reach ages in excess of...

Southern African forests are naturally fragmented yet hold a disproportionately high number of bird species. Carbon and nitrogen stable isotopes were measured in feathers from birds captured at Woodbush (n-=-27 species), a large afromontane forest in the eastern escarpment of Limpopo province, South Africa. The δ13C signatures of a range of forest...

Stable isotopes (δD, δ13C, δ15N) were measured in adult and juvenile Amur Falcon Falco amurensis feathers to understand the migratory connectivity of this species. Using the OIPC (Online Isotopes in Precipitation Calculator) and a calibration curve for American Kestrels Falco sparverius we predicted the breeding range of South African Amur Falcons...

The diets of Falco amurensis and F. naumanni were investigated by analysing the respective stomach contents of 64 and 22 individuals killed during a severe thunderstorm in December 2004. Interpretations of diet were made by considering (1) biomass of dietary items and (2) presence/absence of dietary items in the stomachs analysed. A single beetle (...

Local movements of 374 Malachite Sunbirds, Nectarinia famosa, and 124 Gurney's Sugarbirds, Promerops gurneyi, were studied in KwaZulu-Natal over a period of 92 months. It was hypothesized that these nectarivores move in response to seasonal nectar sources. One Malachite Sunbird moved between two sites and 17 were recaptured at the site of ringing (...

We investigated primary moult and morphometrics in the Green-winged Pytilia Pytilia melba during a six-month period (May–October) in central South Africa. A total of 157 pytilias were captured; 80 (51.0%) of these were in active primary moult during all months of the study. The Underhill-Zucchini model was not applicable for determining moult durat...

Aloe marlothii and A. greatheadii var. davyana are two sympatric winter-flowering succulents that occur in the summer rainfall regions of northern and north-eastern South Africa. Both have flower characteristics that are strongly suggestive of bird pollination, although their nectar differs in volume and concentration. We conducted pollinator exclu...

There is confusion in the literature concerning the taxonomic status of the Turdus smithi - T. olivaceus species complex. Here we attempt to clarify morphological differences within this complex. In addition, we attempt to clarify identification of the respective taxa. Although mean measurements of morphometric features differed significantly betwe...

There is confusion in the literature concerning the taxonomic status of the Turdus smithi – T. olivaceus species complex. Here we attempt to clarify morphological differences within this complex. In addition, we attempt to clarify identification of the respective taxa. Although mean measurements of morphometric features differed significantly betwe...

Aloe marlothii is a CAM succulent plant which is widespread in the northern and north-eastern summer rainfall region of South Africa. Flowering occurs during dry winter months (June–September) and the large inflorescences attract a wide range of birds. Flowering phenology and nectar production were studied during three seasons (2005–2007) at a dens...

Abstract We examined variation in bird species richness, abundance and guild composition along an agricultural gradient in New Guinea, and looked for any additive influence of habitat heterogeneity on these variables. The study was based on a grid of survey plots, six plots wide and 24 plots long with the long axis running from a settlement 2.4 km...

The Grey-headed Parrot Poicephalus fuscicollis suahelicus has a widespread distribution in sub-Saharan Africa yet is uncommon in its natural range. In some areas seasonal movements are recorded. This study, conducted in north-eastern South Africa, showed that habitat use varied seasonally between two sites, Levubu and Makuya. Differences in habitat...

In southern Africa, Aloe marlothii flowers during the dry winter season and offers copious dilute nectar to a variety of birds. Avian abundance and community composition were monitored at an A. marlothii forest at Suikerbosrand Nature Reserve, South Africa. Sampling occurred during two summer months (February–March) when no flowers were present, an...

It is important that conservation strategies consider the needs of taxa that range over large areas or make significant daily or seasonal movements across areas or habitats, but data on movements in most tropical animal species is lacking. We examined frequency, direction, and temporal variation in supra- canopy flight activity ( number of individu...

In comparison with other tropical forest land uses such as selective logging, little is known of the impacts on wildlife of the many forms of small-scale agriculture practised across the tropics. We present density estimates, derived using a point count distance sampling method, for 31 bird species in primary forest, old abandoned gardens and activ...

Wild parrots represent one of the greatest commercial interests in the legal trade in wild birds. Although it is difficult to quantify, there is a considerable illegal trade in wild parrots. Thirty-six per cent of the world's parrot species are listed by the International Union for the Conservation of Nature as threatened or near threatened, and 55...

Numerous New Guinea birds, mostly psittaciforms and columbiforms, have been recorded feeding on soil. This study documents geophagy in the Crater Mountain Wildlife Management Area (CMWMA) in the Eastern Highlands of Papua New Guinea. We present the first documented case of geophagy in the palm cockatoo Probosciger aterrimus and in up to 11 other sp...

Despite New Guinea's importance for parrot species, there is an almost total lack of quantitative data on abundances or habitat associations of parrots on the island. We present such data for 15 parrot species within the species-rich (21 species) Crater Mountain Wildlife Management Area, Papua New Guinea. The four most abundant parrot species made...

Little is known about snags in South African indigenous forests. Because of their value to wildlife, we initiated this study to quantify snag characteristics and dynamics. We also investigated forest structure (woody component and snags) and forest use by avian species of conservation concern. We examined tree species composition, abundance and tre...

The Greyheaded Parrot breeds in Northern Province, South Africa and south-east Zimbabwe (the southern limit of its range) from April to August, yet further north breeds in other months of the year. Egg laying between monogamous pairs is synchronous and 2–4 eggs are laid in natural cavities in Baobabs (Adansonia digitata). Post-breeding seasonal mov...

Seasonal movements of grey-headed (brown-necked) parrots were recorded in parts of its range and are likely a response to breeding and availability of specific food sources. Breeding occurred in the northern Kruger National Park and lowveld near the Mutale-Luvhuvhu river confluence from April to August. Aggregations and movements of birds occurred...

Daily activity and flocking behaviour patterns of the Greyheaded Parrot Poicephalus fuscicollis suahelicus Reichenow 1898 were studied during the non-breeding (August-December) and breeding (March-August) season in Northern Province, South Africa. Correcting for sunrise and sunset, similar patterns of peak flight activity were observed at two sites...

The Greyheaded Parrot, Poicephalus fuscicollis suahelicus, feeds on at least 25 tree species through its range. In Northern Province, South Africa, it was recorded feeding on the fruit of six tree species during the non-breeding season (August–December) and eight species during the breeding season (April–August). It was also recorded feeding on the...

Presence data were recorded and analysed for avian bird species in a study of three separate Afromontane Forests in the KwaZulu-Natal Midlands, South Africa. Levels of endemism for South Africa and forest-specificity were investigated. In total, 136 species were identified utilizing forest, yet not all species occurred in all three forests. Slight...

Cope Parrots, Poicephalus robustus, occur in Podocarpus (yellow-wood) Afromontane forest patches from the Eastern Cape to southern KwaZulu-Natal, South Africa, They are food nomadics moving locally between forest patches in search of food, and occasionally make long foraging forays. Cape Parrots are dietary specialists feeding primarily on endocarp...

In Africa, four genera represent the family Psittacidae; of these, the genus Poicephalus Swainson is endemic and comprises nine species. Three subspecies of the Cape Parrot, Poicephalus robustus (Gmelin), are often recognized. The endangered nominate subspecies, P. r. robustus, inhabits afromontane forest habitats and is endemic to South Africa. Po...

Breeding biology and nesting requirements of Cape Parrots in their natural habitat and in captivity were investigated. Few nests were found, suggesting that nest-sites are limiting, and that the parrots have specific nesting requirements. Nests were secondary cavities in dead Podocarpus spp. (branches), high up in forest canopy trees. Breeding usua...