During the last decades ecology and behaviour have become of major importance in African ornithology. Not only have more individual species been studied in detail, but behaviour and ecology have been used in a more general sense in regional works (Benson et al 1971} and in zoogeographical treatises (Moreau 1966, Hall and Moreau 1970). As part of a world- wide trend, behaviour and ecology have also become important in systematics and taxonomy eg. Hall's 1963 study of francolin, and Benson et al's 1971 erection of the bush shrike family Malaconotidae. This dissertation fits into this trend, beginning with a detailed study of the ecology and behaviour of three species of hornbill of the genus Tockus, and extending the observations in less detail to five other members of the genus. Combined with the literature, these observations allow an analysis of the systematics and evolution of the genus Tokus to be undertaken, as well as supplying descriptive information on Tokus biology. Intro. p. 1.

Thesis (M.A. (African Languages)) -- University of Limpopo, 2013 / Refer to the document

The Fynbos biome in south-western South Africa is a global biodiversity hotspot vulnerable to climate change. Of the six Fynbos-endemic passerines, Cape Rockjumpers (hereafter Rockjumpers; Chaetops frenatus) are most vulnerable to increases in temperature, with population declines correlated with warming, and low physiological heat thresholds. Rockjumper’s preferred mountain habitat is predicted to decrease as they lack opportunity to move to cooler regions as temperatures warm. As Rockjumpers currently occupy the coldest regions of the Fynbos, I hypothesized their thermal physiology would show cold adaptation at the expense of lowered ability to cope with higher temperatures. I aimed to determine the seasonal 1) maintenance metabolism and cold tolerance, and 2) thermoregulatory responses to high temperatures of Rockjumpers. I measured seasonal maintenance metabolic rate, thermal conductance, and maximum thermogenic capacity. I also measured seasonal resting metabolic rate, evaporative water loss, evaporative cooling efficiency, and body temperature at high air temperatures. In winter, Rockjumpers had higher maximum thermogenic capacity, lower maintenance metabolic rate, and lower thermal conductance. Lower maintenance metabolic rates (and thus, lower metabolic heat production) combined with the decreased thermal conductance, confers substantial energy savings in winter. The increased winter maximum thermogenic capacity of Rockjumpers was expected, although the mean seasonal values fell below those expected for a ~ 50 g bird using a global data set, suggesting Rockjumpers are not especially cold tolerant. I further show that in summer Rockjumpers had higher elevations in resting metabolic rates, evaporative water loss, and body temperature, denoting higher rates of heat production and lower heat thresholds in summer compared to winter. My results suggest that Rockjumpers are best suited for relatively mild Krista Oswald Dissertation Chapter 1: General Introduction temperatures. While I found further support for a physiological basis for declining Rockjumper populations, further studies on other mechanisms Rockjumpers may possess to cope with climate warming (e.g. behavioural adjustments) are needed in order to truly understand their vulnerability to climate change.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Human-modified habitats form increasingly large components of landscapes, threatening biodiversity and creating challenges for conservation. In some cases altered habitats form entirely novel ecosystems that may support new combinations of species and species abundances, and create habitat space in otherwise transformed landscapes. In the Western Cape of South Africa, woody invasive species contribute to landscape-level habitat transformation and form novel ecosystems. Invasive Australian Acacia species are especially problematic in lowland areas where they create dense thickets and substantially transform both biotic communities and abiotic processes. Despite the prominence of Acacia thickets across the Western Cape, their ability to support native fauna is not well understood and the objective of this study was to assess the significance of Acacia thickets as habitat for the region’s avifauna. Birds were surveyed in Acacia thickets in the south-western Western Cape in three seasons to examine species richness, abundance and functional abundance. Furthermore, I examined the extent to which differences in patch-level vegetation structure alter bird communities. Between survey sites and seasons, significant variation was observed in assemblage richness, density, median body size and biomass. Variation in vegetation density, stem density, mean vegetation height and total canopy cover best explained variation in bird assemblages. Eighty species were estimated to utilize Acacia thickets and assemblages had a mean density of 7.78 birds per ha. The most abundant feeding guilds were the mixed feeders and insectivores. The median body size observed was 15.2 g and the body size frequency distribution of all species in Acacia spanned a similar range compared to the body size frequency distribution for the species list for the entire Western Cape. The mean biomass of bird communities was 0.224 kg per ha. Using data on bird density and biomass, Acacia thickets across the Fynbos Biome support and estimated average of over 21 million birds with a combined biomass of over 600 thousand kg. This study found that Acacia thickets in the Western Cape support a subset of the region’s birds with the most abundant species being small mixed feeders, which are also frequently urban-adapted. Compared with other habitat types, Acacia support bird assemblages with moderate species richness and density. This study shows that Acacia thickets, as a novel habitat, provide a significant amount of habitat space in a highly transformed landscape and highlights the need for comprehensive evaluation of altered habitats before assumptions are made about their ecological value. / AFRIKAANSE OPSOMMING: Getransformeerde habitatte maak vermeerderend groot deel uit van die omgewing, dit bedreig biodiversiteit en skep groter uitdagings vir bewaring. In sommige gevalle vorm hierdie getransformeerde habitatte geheel nuwe ekosisteme wat moontlik nuwe kombinasies van spesies en spesie volopheid kan onderhou. Verder skep nuwe ekosisteme habitat spasie in anders veranderde landskappe. In die Wes-Kaap van Suid-Afrika dra die Australiese Acacia indringer spesies is veral problematies in laagliggende areas, aangesien dit digte ruigtes vorm, asook beide die biotiese gemeenskappe en die abiotiese prosesse aansienlik transformeer. Ten spyte daarvan dat daar volop Acacia ruigtes in die WesKaap is, word min verstaan van hul vermoë om inheemse fauna te onderhou. Die hoofdoel van hierdie studie was om die belang van Acacia ruigtes as habitat vir die area se voëllewe te bepaal. Voël-opnames in die suidwestelike dele van die Wes-Kaap is gedoen in Acacia ruigtes oor drie seisoene, om spesierykheid, volopheid en funksionele volopheid te ondersoek. Verder is die mate waartoe verskille in die plotte van die plantegroei struktuur, die voëlgemeenskappe verander, geondersoek. Daar was aansienlike variasie waargeneem in die spesiesamestelling rykheid, voorkoms digtheid, mediaan liggaamsgrootte en biomassa van die voëls tussen die onderskeie voëlopnaam plotte en die seisoene. Die variasie in plantegroei digtheid, stam digtheid, mediaan plantegroeihoogte en totale kroonbedekking verduidelik hierdie variasie in spesiesamestelling die beste. Tagtig voëlspesies Acacia ruigtes benut en die populasiesamestelling het ‘n gemiddelde digtheid van 7,78 voëls per ha. Die mees algemene voel-voeding-guldes was die gemengde-voedsel-vreters en insekvreters. Die median liggaamsgrootte waargeneem was 15,2 g en die liggaamsgrootte frekwensieverspreiding van alle spesies in Acacia ruigtes is ooreenkomstig met die liggaamsgrootte frekwensieverspreiding vir die spesielys vir die hele Wes-Kaap. Die gemiddelde biomassa van voel gemeenskappe was 0.224 kg per ha. Acacia ruigtes oor die fynbosbioom wat ‘n geskatte gemiddelde van meer as 21 miljoen voels ondersteun, met ‘n gesamentlike biomassa van meer as 600 duisend kg. Hierdie studie het bevind dat Acacia ruigtes in die Wes-Kaap ‘n onderafdeling van die streek se voels ondersteun, met die mees algemene spesies as die klein gemengde-voedsel-vreters, wat ook dikwels stedelik aangepas is. In vergelyking met ander habitattipes ondersteun Acacia ruigtes voel samestellings met matige spesierykheid en digtheid. Hierdie studie toon dat die Acacia ruigtes, as ‘n nuwe habitat, ‘n beduidende hoeveelheid habitat ruimte in ‘n hoogs getransformeerde omgewing skep en beklemtoon die behoefte aan ‘n omvattende evaluering van veranderde habitatte, voor aannames gemaak word oor hul ekologiese waarde.

Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2012 / Sparrow-larks form a relatively small genus in the family Alaudidae and comprise only seven species distributed widely throughout Africa and parts of the Eurasian landmass. Sparrow-larks are unique amongst larks in that they are sexually dichromatic and exhibit biparental care. The chestnut-backed sparrow-lark Eremopterix leucotis is endemic to Africa with five subspecies recognized based on differences in plumage colouration. The five subspecies are distributed throughout the arid to semi-arid savannas of Africa with two subspecies (E. l. hoeschi and E. l. smithi) occurring in southern Africa. Despite their widespread occurrence and its interest for research on the evolution of characteristics in the family (e.g. being sexually dichromatic and exhibiting biparental care), very little is known of the biology and ecology of the Eremopterix larks. The chestnut-backed sparrow-lark is no exception and most of what we know of the species is based on incidental observations from a few nests. In an attempt to improve our knowledge of this interesting group of species, it was decided to study various aspects of the breeding biology and ecology, moult, vocalizations and geographical variation in the chestnutbacked sparrow-lark. The breeding biology of the chestnut-backed sparrow-lark was studied at Al3 farm (De Loskop) near Mogwadi in the Limpopo Province of South Africa from January 2008 to December 2010. Data collected during the study included: breeding seasonality, egg and clutch characteristics, duration of the incubation and nestling periods, nest-site characteristics, the roles and relative contribution of the sexes in the breeding cycle, nestling development, diet and nestling provisioning rate, and breeding success. Chestnut-backed sparrow-larks bred mostly during the dry season, which is from April to September in the study area. Nevertheless, the results revealed that breeding is bimodal with a main peak in breeding activity in late summer and autumn (March to April) and a second smaller peak in spring (September to October). The species showed geographical variation in clutch size with a mean of 1.88 eggs recorded in the study area as opposed to 1.00 recorded in the northern parts of its range. Egg dimensions compared well with measurements obtained from the Nest Record Card Scheme of the Animal Demography Unit, University of Cape Town, South Africa. The mean incubation period of 10.33 days recorded in this study compares favourably with that of other Eremopterix species viii (8–10 days), a genus with some of the shortest incubation periods amongst larks. The mean nestling period of 9.2 days (range: 8–10) in the study area was significantly less than the 10–12 days reported for populations in the northern range of the species, but it compares well with those of other sparrow-larks. Nest site characteristics, which were quantified within a 1 m2 quadrant with the nest as the centre, including nest dimensions, were consistent with those reported in the literature. Chestnut-backed sparrow-larks in the study area preferred to nest in areas with a high percentage of bare ground (median = 67.5%) and very little vegetation cover (median = 25%). Most nests faced in a southerly direction compared to nests in the north of the species’ range, which face in a north-easterly or easterly direction. The species’ preference to face the nests away from the midday sun most probably serves a thermoregulatory function to avoid excessive heat during the warmest parts of the day. Most nests (78.2%) had an apron varying in size from small and insignificant to large and well-developed. The functional significance of the apron remains a matter of conjecture and there was no association between breeding success and presence or absence of the apron. In addition, one pair constructed one nest with and another without an apron, suggesting that individual preference or characteristic is not a determinant factor in the construction of an apron. Both sexes took part in nest construction, incubation and feeding and brooding of nestlings. However, the relative contributions were not entirely symmetrical as males incubated a greater proportion (50.1%) of the time compared to females (43.1%), and the mean and median of male incubation shift lengths were longer than that of females, albeit not statistically significant. However, females made statistically significantly (P < 0.05) more nest visits to deliver food compared to males (54.6% vs. 45.5%). The average breeding success, estimated using Mayfield’s method, was 16.1% but there were inter-annual differences with the overall breeding success in 2010 being only 8.1% compared to 20.6% of 2008. Known causes of failure included nest depredation, flooding, starvation, nest abandonment and hatching failure. Statistical analysis of morphometric data of live specimens and museum study skins suggest that, in addition to being sexually dichromatic, chestnut-backed sparrowlarks also exhibit mild sexual size dimorphism. However, there was considerable overlap in these measurements between the sexes and as a result the biological significance of this sexual size dimorphism may be negligible. Nevertheless, the ix results show chestnut-backed sparrow-lark males tend to have longer wings and tails compared to females. This may be adaptive with respect to the extended display flights that males perform during the breeding season. Interestingly, the mean mass of breeding females in the study area was significantly more compared to males, whereas the SAFRING database, representing data recorded throughout the year, showed no significant differences in the mean mass between the sexes. The greater mass of breeding females may relate to physiological changes associated with the acquisition of resources and the development of structures and tissues associated with egg-laying and egg-production. Larks rely heavily on vocalizations to attract mates and advertise territories. Not surprisingly, the study revealed a rich vocal repertoire for the chestnut-backed sparrow-lark. The analysis of the vocalizations shows that chestnut-backed sparrowlarks have a display song performed by males, a sub-song sung by both sexes and various different calls used in different contexts, e.g. flight and alarm calls. The study also presents the first analysis and description of the vocalizations of nestlings. An interesting feature of the vocalizations of the chestnut-backed sparrow-larks was that they performed hetero-specific vocal mimicry, which was incorporated in the subsong. Moult is a relatively unknown aspect in the annual cycle of the majority of larks. Chestnut-backed sparrow-larks undergo post-breeding moult, which is an adaptation to reduce the conflict between moult and breeding as both activities have high energy demands. The moult study also showed that they undergo a partial moult in mid-winter, involving the inner-most secondaries and some of the contour feathers. The results of this study shed valuable light on the natural history of this species and contributed significantly to ornithology and our growing understanding of the biology and ecology of the family. The results can also form a basis for future inter- and intraspecific comparative studies. The study illustrates the importance of undertaking long term studies of species to account for inter-annual differences in various ecological parameters.

Lanner Falcons Falco biarmicus are the commonest large falcons in Africa and this study in the coastal area of the Eastern Cape Province, South Africa investigated their ecology from 1984 to 2000. Lanners have recently been categorised as near-threatened and this study was initiated to ascertain if the population was stable. Breeding success of a small population, in different habitat types, was monitored intensively from 1997 to 2000, and the factors that inhibited breeding were investigated. The earliest onset of incubation was 17 July and the latest 16 August, with 2.2 young fledged per breeding pair over the four-year period. Incubation lasted 32 days and young fledged after 42-45 days. All nest sites were on cliffs with a mean height of 114 m, a mean vertical face of 53 m; 45% of the nests were in ravens’ nests. The aspect of cliff sites also influenced breeding success. Radio tracking was used to determine home range, habitat use and hunting methods, with prey species identified. Home ranges were between 66 km² and 249 km². Preferred prey was domestic chickens, pigeons and small birds during the breeding season. Foraging ranges were smaller in intensively cultivated areas with seed crops. Data obtained from ringing returns showed that no long distance movements occurred in this region, but two juveniles dispersed 152 km and 127 km. Conservation aspects with possible threats to Lanner Falcons such as poisons, electrocutions and direct persecution are discussed with some recommendations made for future research. Evidence from this study indicates that Lanner breeding success is not limited by nest site availability, but by rainfall timing and prey availability. Lanners foraged more in open areas than areas with tall vegetation, and benefited from intensive agriculture. This population appeared to be healthy and in no danger of declining in the near future.

The three South African crane species, namely, the Wattled Crane (Bugeranus carunculatus), the Blue Crane (Anthropoides paradisea) and the Grey Crowned Crane (Balearica regulorum regulorum) are all threatened. South African legislation protects the cranes, however eggs and/or fledglings are sometimes illegally collected from the wild. These are then sold, often by registered breeders, who falsely claim them as the offspring of their captive breeding pair. DNA fingerprinting is one method to detect this crime. Fifteen RAPD primers were screened for polymorphism in the three species. Seven primers produced polymorphic profiles in the Blue Crane and eight each in the Grey Crowned Crane and Wattled Crane, with an average of 14.57, 12.38 and 5.88 scorable loci per primer, respectively. The Band Sharing Coefficient for unrelated individuals was found to be 0.665, 0.745 and 0.736 for the Blue, Grey Crowned and Wattled Crane respectively. Five microsatellite primers, originally developed for use in Whooping Cranes (Grus american), had previously been shown to be polymorphic in the Wattled Crane. This was also the case in this study with an average of 3.6 alleles per primer. Although all primers cross amplified, only a single primer each showed polymorphism in the Blue Crane (showing 6 alleles) and the Grey Crowned Crane (showing 5 alleles). The RAPDs were found to be irreproducible, show high numbers of novel bands and had parent: offspring BSC values that were not significantly higher than those of unrelated individuals. Statistics showed that, in the Blue Crane, the probability that misassigned parents would be detected was low whilst there was an almost certainty that true parents would be incorrectly excluded. The five microsatellite primers examined gave exclusionary powers of 0.869 and 0.641 where one or two parents were unknown in the Wattled Crane. The exclusionary powers for the Blue Crane and Grey Crowned Crane calculated at only one locus were much lower. It was concluded that RAPDs were totally inappropriate for parentage analyses, however, microsatellites are a suitable technique and recommendations are made that other microsatellites, developed for other species of crane, should be examined for their potential in this respect. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Forested areas have been cited for their highly diverse floral and faunal assemblages, which are currently under threat from anthropogenic activities that restrict their range and deplete the resources produced within these naturally fragmented patches. Historically, up to 67 percent of avifaunal species associated with well-treed areas have undergone localised extinctions, consequentially affecting biodiversity as a measure of species richness and ecosystem functionality. To date, more than 900 of the bird species affiliated with forests are under threat and despite the theory surrounding functional redundancy, the mass extinction that is currently underway poses considerable limitations on the ecological integrity of these biomes. In South Africa, indigenous forest (one of the rarest biomes), occurs predominantly in small isolated patches along the eastern escarpment. With mountainous terrain emphasised as ‘prominent hotspots of extinction’, the limited dispersal and habitat sensitivity of montane forest fauna renders these species more prone to localised extinctions. BirdLife International, the IUCN and SABAP2 all indicate reductions in the range and abundance of the Chorister Robin-Chat (Cossypha dichroa) - an endemic forest specialist that is reported to move seasonally between high-altitude forest patches where they breed in summer, and lowland coastal forests where they overwinter. Beyond diet, body morphology and vocalisations, much of the information available on the altitudinal movements of C. dichroa is based on secondary sources and the assumptions therein. This study aimed to investigate the potential utilisation of δ13C and δ15N stable isotopes in determining the dietary niche width and altitudinal movements of C. dichroa. Feathers obtained in forested patches of the Limpopo, KwaZulu-Natal and Eastern Cape provinces exhibited a wide trophic niche width and generalised diet. Strong regional separation is apparent in the isotopic signatures suggesting little movement between provinces. A comparison of 13C-isotopes showed minimal variation that point to a uniformity in the carbon-base utilised by C. dichroa across their range. The 15N-signatures obtained in Limpopo, however, revealed a distinct trophic segregation between the northern-most Chorister populations and their southern counterparts. No altitudinal movements were detected in the isotopic signatures of recaptured Choristers, but more research is needed to investigate the long-term accuracy of these results and the breeding potential of resident Choristers in lowland coastal forests; especially when considering the reduced range and abundance reported for this endemic species.

Thesis (MA)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: This study addresses the problem of Blue Crane (Anthropoides paradiseus) collisions with power lines in the Overberg region, home to approximately 50% of South Africa's national bird's global population. The low visibility of power lines against the landscape is considered to be the major cause of collisions. These claim at least 20 birds annually, which is a considerable loss to a vulnerable species. For this study, expert knowledge of the Blue Cranes' biology, general behaviour and use of its habitat were compiled. These were then translated into rules that were integrated into a Geographic Information System (GIS) to establish a predictive model, which attempts to identify and quantify risk power lines that Blue Cranes are most likely to collide with. The criteria that were considered included landscape proximity of power lines to water bodies arid congregation sites, land cover, power lines orientation in relation to predominant wind directions (North Westerly and South Easterly) and visibility of the power lines against the landscape. The power lines were ranked as highest, high, medium, low and no risk. It is recommended that this classification be used to prioritize the proactive marking of power lines with bird flappers in order to reduce collisions. The results show that 27% of the power lines in the study area pose the highest risk and should therefore be marked immediately. The power lines classified as high (1%), medium (28%) and low risk (21 %) should be marked over short, medium and long term, respectively .. The study demonstrated the potential of GIS in the conservation of Blue Crane. The GIS model developed in this study can be applied in areas of similar habitat such as the Swartland or with some modifications in a slightly different habitat such as the Karoo. It is envisaged that the results of this study will be of great value to the ESKOM (South African Electricity Commission) and Endangered Wildlife Trust (EWT) Partnership and conservation authorities in the effort to save the Blue Crane. / AFRIKAANSE OPSOMMING: Hierdie studie het die probleem van botsings deur Bloukraanvoëls met kraglyne in die Overberg-omgewing van die Wes-Kaap ondersoek. Die Overberg-omgewing huisves ongeveer 50% van Suid Afrikaanse nasionale voël se wêreldbevolking van Bloukraanvoëls, en aangesien kraglyne normaalweg nie maklik sigbaar is teen die landskapsagtergrond nie, verhoog dit, tesame met die biologiese eienskappe van Bloukraanvoëls, die waarskynlikheid dat die voëls met kraglyne sal bots. Hierdie botsings met kraglyne eis minstens 20 Bloukraanvoëls per jaar, wat 'n aansienlike en beduidende aantal vir 'n kritiese bedreigde spesie is. Die studie het gepoog om spesialiskennis oor Bloukraanvoël-biologie, algemene gedrag en habitatgebruik, om te sit in 'n stel reëls, wat in 'n Geografiese Inligtingstelsel (GIS) geïntegreer is om 'n voorspellingsmodel te bou. Hierdie voorspellingsmodel is aangewend om kraglyne wat 'n hoë risiko vir Bloukraanvoëls inhou, te identifiseer en die waarskynlikheid vir botsings te kwantifiseer. Die model aanvaar dat die volgende omgewingsfaktore in die Overberg-omgewing verband hou met die waarskynlikheid van botsings, naamlik: die nabyheid van kraglyne aan waterliggame of gebiede waar voëls saamtrek, die voorkoms van natuurlike veld, die heersende windrigtings (Noordwes en Noordoos) en lae sigbaarheid van kraglyne teen die donker landskapsagtergrond. Die geïdentifiseerde kraglyne is as eerste-, tweede, derde. en vierderangse prioriteit geprioritiseer om as riglyn te dien vir die proaktiewe aanbring van flappers (wat dit ten doel het om voëlbotsings te verminder) deur ESKOM. Die studie het bevind dat 27% van die kraglyne in die Overberg-omgewing eersterang prioriteite is, en dat hierdie kraglyne onmiddellik gemerk sal moet word. Die tweederang prioriteit kraglyne (1%) saloor die mediumtermyn gemerk word, terwyl die derderangse prioriteit kraglyne (28%) oor die langtermyn gemerk sal word. Die vierde prioriteit kraglyne (21 %) kon oor die langertermyn gemerk word. Die studie het die omvang van die probleem, sowel as die rol van GIS in die bewaring van die Bloukraanvoëls beklemtoon. Die GIS-model wat in die studie ontwikkel en gebruik is, kan in soortgelyke gebiede soos die Swartland, of in ietwat verskillende omgewings soos die Karoo getoets word, met die doelom die habitatvoorkeure van Bloukraanvoëls beter te verstaan en navorsers te help om 'n beter begrip van die model te ontwikkel en sodoende die resultate te verbeter. Dit word voorsien dat hierdie studie en verslag baie belangrik sal wees vir die ESKOM-EWT Vennootskap en ander betrokke bewaringsorganisasies in 'n poging om Bloukraanvoël-bewaring aan te help.

The dispersal of plants with particular attention to the roles birds play as dispersal agents was studied in the southwestern Cape, South Africa from 1983 to 1985. The research was organized as ten inter-related studies, each with an independent data base. Each chapter focused on a different scale of plant dispersal processes ranging from regional assemblages of plant species to individual species. At the largest scale, the seven vegetation types commonly occurring in the southwestern Cape were examined for incidence of vertebrate-dispersed plants. Coastal Thicket and Afromontane Forest were found to be the richest in these species. The colonization of vertebrate-dispersed plants was examined in an artificially cleared area of Mountain Fynbos vegetation. Enhanced densities of vertebrate-dispersed species were found in areas where perches had been provided. The seasonal availability of vertebrate-dispersed species was found to be most continuous in Coastal Thicket vegetation. Fruit displays of vertebrate-dispersed indigenous plants were found to vary from those that were sporadic and inconspicuous, to those that were conspicuous and predictable, whereas those of alien plants were usually large and conspicuous. Avian use of these fleshy fruits in Coastal Thicket was examined and found to be proportional to their availability. A study of fruit presentation in relation to leaf number and stem thickness suggested that sessile, stem attached fruits have fewer local leaves at time of ripening than fruits which are presented in panicles. This may enhance accessibility and conspicuousness of stem attached fruits for dispersal by birds. Four autecological studies tested certain predictions arising from models developed to describe fruit/frugivore interactions. The dispersal of the alien Acacia cyclops seeds by the indigenous Black Korhaan Eupodotis afra suggested that successful fruit/frugivore relationships are not necessarily the product of reciprocal evolution. The study on Chrysanthemoides monilifera found that efficient dispersal systems are not limited to plants producing small quantities of lipid-rich fruits and to dispersal by obligate frugivores. The abiotic dispersal of Quercus robur was found to be efficient in relation to vertebrate-dispersal. The study on Protasparagus aethiopicus found that the morphology of fleshy fruits may also reflect attempts to overcome the effects of non-dispersing seed predators. 1It is concluded that a gradient from a predictable to unpredictable fruit availability provides a better basis for studying fruit/frugivore interactions than the coevolutionary models. previously presented.