Craig T. Symes

Response of avian nectarivores to the flowering of Aloe marlothii: a nectar oasis during dry South African winters

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, and six months (May–October) that spanned the winter flowering. We hypothesized that an influx of occasional nectarivores to the A. marlothii forest during flowering would lead to significant changes in the avian community. Overall bird abundance increased 2–3 fold at the peak of nectar availability (August). We recorded 38 bird species, of 83 species detected during transects, feeding on A. marlothii nectar; this diverse assemblage of birds belonged to 19 families, including Lybiidae, Coliidae, Pycnonotidae, Sylviidae, Cisticolidae, Muscicapidae, Sturnidae, Ploceidae and Fringillidae. Surprisingly, only two species of sunbird (Nectariniidae) were observed feeding on A. marlothii nectar, and both occurred in low abundance. We predicted that competition for nectar resources would be high, but few aggressive inter- and intra-specific interactions occurred between birds while feeding on inflorescences. During peak flowering, insect feeders (insectivores, omnivores, nectarivores) fed on nectar during the cold morning when insect activity was low, whilst non-insect feeders (frugivores and granivores) fed on nectar in the middle of the day. Our study highlights the importance of A. marlothii nectar as a seasonal food and water source for a diverse assemblage of occasional nectarivores.

Research and conservation of the larger parrots of Africa and Madagascar: a review of knowledge gaps and opportunities

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 populations, the threats they face and knowledge gaps. Here we begin to address this shortfall for the larger species in the region belonging to the genera Coracopsis, Poicephalus, Psittacus and Psittacula. We review developments since the production of the IUCN Parrot Action Plan published in 2000, identify areas where critical knowledge is lacking and highlight opportunities to address them. While advances have been made over the last decade, progress has not been evenly spread, with a strong bias towards populations in southern Africa. To date much research has focused on describing aspects of ecology and behaviour and there remains a need for studies determining the current status of populations and the factors limiting distributions and abundance. This review aims to provide a basis upon which progress towards an improved understanding of the conservation needs of the larger parrots of Africa and Madagascar can be made.

Breeding biology of the Greyheaded Parrot (Poicephalus fuscicollis suahelicus) in the wild

Abstract 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 movements occur into regions where nest sites are scarce or possibly absent. Males provision the female in the nest cavity during incubation and the early stages of nestling development. Attendance at the nest by the female is reduced once fledglings are able to thermoregulate on their own. By the end of the fledging period visitation rates to the nest site by the male and the female are reduced to twice a day (mid-morning and late-afternoon). Nest sites are possibly limiting, with interspecific competition for nest sites occurring. Intraspecific competition for nest sites in areas where populations have declined has possibly been reduced. Removal of chicks from nests by humans threatens populations outside protected areas. The conservation of this species in the southern limit of its range is thus highlighted.

Assessing the diet of Amur Falcon Falco amurensis and Lesser Kestrel Falco naumanni using stomach content analysis

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 (Coleoptera) species, cf. Heteronychus arator, made up the majority of stomach contents when using both methods. Other Coleopteran taxa did not comprise a significant proportion of the biomass in each stomach but were well represented in the stomachs of many individuals. Taxa less represented included Rodentia, Solifugae, Orthoptera, Hymenoptera and other unidentified prey items. Although both F. amurensis and F. naumanni sometimes feed on birds, we believe that all feathers found in stomachs were ingested during preening activities or were accidentally introduced during excision. The presence of a single beetle species in the diet of both species demonstrates the importance of episodic and/or predictable arthropod irruptions as a food source for these two migrant falcon species. Similarity in the stomach contents of both species indicates that both may face similar threats with regards to pesticide exposure, habitat alteration and persecution in their austral non-breeding range.

Migratory connectivity and conservation of the Amur Falcon Falco amurensis : a stable isotope perspective

Stable isotopes (δD, δ 13 C, δ 15 N) 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 in the Palaearctic. δD values for juvenile feathers (mean ± SE = -58.1 ± 2.5‰, range -83.9 to -25.7‰) and predicted Palaearctic annual precipitation values indicated that juvenile Amur Falcons in South Africa originated from across their entire Palaearctic range. This rejects the leapfrog migration hypothesis and suggests the widespread movement of birds south, with a funnelling effect into the subregion where they become concentrated over a narrower distribution range. Adult δD f values were more depleted (-37.4 ± 1.8‰, range = -71.3 to -9.3‰) than predicted annual precipitation values for sites where feathers moulted in South Africa (-20.2 ± 0.9‰) but there was no correlation between δD p and δD f . This, together with significant variation of δ 13 C among sites and annual fluctuations in roost sizes, suggests that roost site fidelity is low in the overwintering range. Populations not confined to breeding sites in South Africa are able to move widely across the subregion, feeding on a broad range of arthropods that become seasonally abundant during the austral summer. Total population estimates for South Africa are significantly lower than global estimates so a significant proportion of the population may not overwinter in South Africa or global populations are significantly lower than estimated. In South Africa, roosts that number hundreds to thousands of individuals are often in large exotic trees, e.g. Eucalyptus sp. They are often tolerant of disturbance at roosts which may be of little concern for their conservation. Habitat changes in the overwintering range in South Africa though, particularly due to agriculture, afforestation and strip mining, may affect global population numbers. There is also concern over the persecution of birds along their migratory route.

Seasonal occurrence of the Malachite Sunbird, Nectarinia famosa, and Gurney's Sugarbird, Promerops gurneyi, in KwaZulu-Natal, South Africa

Local movements of 374 Malachite Sunbirds, Nectarinia famosa, and 124 Gurneys 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 (4.6%, recapture rate). Although no long-distance recoveries of Gurneys Sugarbird were mode, the presence or absence of this species at ringing sites suggests that they are involved in local long-distance movements between food sources. Twenty-six recaptures (16.1% of individuals ringed) indicate strong site fidelity.

Patterns of supra-canopy flight by pigeons and parrots at a hill-forest site in Papua New Guinea

Abstract 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 individuals recorded per hour of recording) of eight species of parrot and seven species of pigeon over 5 months in a New Guinean hill-forest. Papuan Mountain Pigeon (Gymnophaps albertisii) contributed 44% of all flights and Sulphur-crested Cockatoo (Cacatua galerita) 17%; while 95% of 1800 flights were made by seven species. Directions of flights were non-random in nearly all species. There was a significant movement of Papuan Mountain Pigeon, and smaller movements of Dusky Lory (Pseudeos fuscata), Rainbow Lorikeet (Trichoglossus haematodus) and Eclectus Parrot (Eclectus roratus), towards lower altitudes in the mornings and a varying return to higher altitudes in the afternoons. Most species made more supra-canopy flights in the mornings than the afternoons but the exact patterns of flight differed between species. Flight activity varied significantly between months in several species, and flight activity tended to be highest during periods of breeding in most frugivorous birds. Large-bodied species made more supra-canopy flights than did smaller species, but there was no relationship across species between ‘on-the-ground’ bird densities and flight-frequency. Breadth of frugivorous diet (determined by review of the literature) did not influence flight-frequency. The factors that underpin the highly variable patterns of movement were identified. How these patterns might be affected by changes in land-use is important for landscape-level conservation, especially for those species that make systematic long-distance movements.

Population genetic structure and long-distance dispersal of a recently expanding migratory bird

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 general biodiversity impoverishment or the spread of allochthonous diseases. We explored the genetic structure and potential population mixing on the recently range-expanding European bee-eater Merops apiaster. In addition, the species is suspected of harbouring and disseminating the most relevant disease for bees and apiculture, Nosema microsporidia. In agreement with complementary ringing recovery data and morphometric measurements, genetic results on two mitochondrial genes and 12 microsatellites showed a reasonably well-structured population partitioning along its breeding distribution. Microsatellite results indicated that not only did a few birds recently disperse long distance during their return migrations and change their natal breeding areas, but also that a group of allochthonous birds together founded a new colony. Although we did not provide evidence on the direct implication of birds in the widespread of Nosema parasites, our finding on the long-distance dispersal of bird flocks between remote breeding colonies adds concern about the role of European bee-eaters in the spread of such disease at a large, inter-continental scale.

Notes on African Crowned Eagle Stephanoaetus coronatus diet in savanna and forest in KwaZulu-Natal, South Africa

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, whilst Samango monkey Cercopithecus albogularis, a common forest species, represented only 1.7% of prey items. Other species made up 5.0% and included a range of species not found in the forest (e.g. Ourebia ourebi, Lepus sp. and Ovis capra). At the savanna nests at least four taxa were identified, of which 73.1% of prey items were adult. The majority of prey items were identified as procaviids (87.0%) with 5.6% and 7.4% of prey items represented by C. albogularis/C. pygerythrus and other remains (e.g. Capra hircus and Philantomba monticola), respectively. In South Africa, where total forest area is reduced compared to regions further north, the dietary range of African Crowned Eagles may include a wider diversity of prey from different biomes; feeding generalisation and opportunism may therefore be an important strategy for the maintenance of African Crowned Eagles populations in the region.

Founder populations and the current status of exotic parrots in South Africa

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 groups popularity as a cage bird, and the transport of vast numbers of individuals across the globe (both legally and illegally), the establishment of populations beyond their natural ranges has likely been enhanced. This review reports on c. 30 parrot species that have been observed outside of their natural ranges in South Africa, most likely derived, and supplemented, from both intentional and unintentional releases. Of these, the Rose-ringed Parakeet Psittacula krameri and at least one Agapornis species have become established as breeding wild populations. Like other invasive species they may pose threats to local biodiversity; however, all are strongly associated with major urban centres where significant changes to natural biota have already occurred.