The breeding biology of the greywing francolín Francolinus africanus and its implications for hunting and management

We studied the breeding biology of the greywing francolín Francolinus africanus on the Stormberg Plateau of the eastern Cape Province, South Africa during 1988–1991. Timing of breeding, nesting behaviour, clutch size, egg size, and clutch survival rates were recorded and compared with published and unpublished information from Natal, the eastern Orange Free State and south-western Cape Province. The greywing breeds during the austral summer throughout its range, with peak laying activity during August-November. However, the nesting period is contracted in the south-western Cape, where it starts about one month earlier and ends three months earlier than in the eastern Orange Free State and the eastern Cape, where laying was recorded from August to March. The greywing's breeding season is more consistently positively correlated with measures of environmental variation in the summer rainfall region than in the winter rainfall region. Flushed single birds were the best indicators of nesting sites. Clutches were incubated by hens only. Mean clutch size was 5,5 (SD = 1,2) and mean egg dimensions were 39,9 mm × 30,1 mm (SD = 1,9 and 0,9). Incubation period was 21,7 days (SD = 0,5), hatching success (the probability that eggs present at hatching time actually produced living young) was 90% and clutch survival rate (the probability that a clutch will survive 21,7 days of incubation) was 31%. Hunting seasons for the greywing should be from 15 April to 31 July in the summer rainfall region and from 1 April to 30 June in the winter rainfall region. Veld burning should cease at the end of August throughout the greywing's range so that disturbance of breeding birds is minimized

Perch availability and ground cover: factors that may constitute suitable hunting conditions for pale chanting goshawk families

We investigated the impact of perch height and abundance, and the cover for prey, on the hunting tactics of perch-hunting pale chanting goshawks (Malierax canorus). Mhough pale chanting goshawks demonstrate a clear preference for perching on the highest available perches, the availability of perches is of more importance than height because these birds hunt almost exclusively from perches, move regularly between them, and an increased number of perches increases the area of habitat accessible for effective hunting. In Succulent Karoe, pale chanting goshawks occupied areas where perch density (16 natural and 122 artificial/25 hal was significantly higher than in unoccupied areas (8 natural and 12 artificial/25 hal. The high proportion of cover formed by natural perches (trees and shrubs; 36%) and the low proportion of open ground (42%) resulted in Closed Spekboomveld being unsuitable for pale chanting goshawks, relative to the adjacent Open Spekboomveld that supported goshawks by offering a less restricted view of the ground and prey (perch cover 18% and open ground 49%). In Karroid Broken Veld, the combination of perch availability (3 026/25 hal and open ground (62%) may provide the most suitable conditions for hunting rodent prey near cover or in the open. We suggest that such habitat may also provide a pathway, through fitness benefits gained, in the development of delayed dispersal and cooperative breeding in pale chanting goshawk families.S. Afr.J. Zool. 1997,32(1

Patterns of distribution, diversity and endemism of larger African Mammals

Patterns of distribution and diversity (= species richness) of larger African mammals, and three subsets thereof (ungulates, carnivores and primates), are identified and analysed quantitatively. Distributional patterns generally correspond well with those of present-day vegetation types and of resident non-aquatic birds. However, the precise locations of zonal boundaries and the degree of zonation differ between groups, primarily reflecting their different ecological requirements. Large mammal diversity increases towards the equator, but diversity patterns differ substantially between the groups. Diversity is positively correlated with vegetation type diversity, and vegetation types analysed as separate units explain over 85% of the variance in the diversity of the mammal groups investigated. In addition, both distributional and diversity patterns appear to have been affected by past environmental factors

Effects of alien woody plant invasion on the birds of Mountain Fynbos in the Cape of Good Hope Nature Reserve

The density, biomass, species richness and composition of birds in plots in two Mountain Fynbos plant-species assemblages (Tall Mixed Fynbos and Restionaceous Tussock Marsh), infested with alien woody plants (mainly Australian Acacia spp.) at the Cape of Good Hope Nature Reserve, South Africa, were compared with those of uninfested plots. The relative density of frugivorous and granivorous birds tended to increase, but total bird density did not change significantly with increasing density of Acacia cyclops in Tall Mixed Fynbos. However, the density of nectarivorous birds decreased with increasing A. cyclops infestation as a result of the elimination of their food plants (proteaceous and ericaceous shrubs). Thus, alien woody plants have the capacity to disrupt the putative avian nectarivore – indigenous plant pollination relationship. Dense infestations of mixed alien species in Restionaceous Tussock Marsh supported fewer nectarivorous birds, but more granivores and insectivores than did uninfested vegetation. Moreover, bird species more typical of woodland and thicket (and absent from uninfested fynbos vegetation), notably large granivores, were found in dense mixed-alien infestations of this plant-species assemblage

Disproportionate mortality of males in a population of springbok (Artiodactyla: Bovidae)

The hypothesis that an imbalanced sex ratio, favouring females, in populations of springbok (Anti-dorcas marsupialis) is the result of disproportionate mortality of males is tested by comparing the sex ratio in a sample of 50 carcasses with that in a population of live springbok from the same geographical area. The results are consistent with this pypothesis. A suggested refinement of the hypothesis is that the disproportionate male mortality falls most heavily on young adult males which are in close association with springbok territories. Possible causes of this age- and sex-linked mortality are discussed

Temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse in South Africa

We examined various measures of temporal and spatial patterns of abundance and breeding activity of Namaqua sandgrouse Pterocles namaqua (presumably mostly for P. n. furvus) in South Africa. Bird-atlas maps indicating reporting-rates and extensive-counts showed that the majority of Namaqua sandgrouse concentrate in Bushmanland, in the north-western Cape Province, from December to March. From April to July the sandgrouse move north and east of Bushmanland and apparently return to Bushmanland from August to November. This west-east movement occurs at a relatively constant rate of 30-50 km per month. Only 15% of the sandgrouse ringed at an estate within the eastern part of this species range returned the following winter. Follicle diameter and brood-patch measurements increased significantly from July to August, at the time when the majority of birds leave the estate. Belly-soaking was more prevalent in early summer in Bushmanland than in any season in the east. South African populations of Namaqua sandgrouse are partial migrants which breed primarily in early summer (October - November) in Bushmanland

Can sexual selection drive female life histories? A comparative study on Galliform birds

Sexual selection is an important driver of many of the most spectacular morphological traits that we find in the animal kingdom (for example see Andersson, 1994). As such, sexual selection is most often emphasized as

On the Study of Hyperbolic Triangles and Circles by Hyperbolic Barycentric Coordinates in Relativistic Hyperbolic Geometry

Barycentric coordinates are commonly used in Euclidean geometry. Following the adaptation of barycentric coordinates for use in hyperbolic geometry in recently published books on analytic hyperbolic geometry, known and novel results concerning triangles and circles in the hyperbolic geometry of Lobachevsky and Bolyai are discovered. Among the novel results are the hyperbolic counterparts of important theorems in Euclidean geometry. These are: (1) the Inscribed Gyroangle Theorem, (ii) the Gyrotangent-Gyrosecant Theorem, (iii) the Intersecting Gyrosecants Theorem, and (iv) the Intersecting Gyrochord Theorem. Here in gyrolanguage, the language of analytic hyperbolic geometry, we prefix a gyro to any term that describes a concept in Euclidean geometry and in associative algebra to mean the analogous concept in hyperbolic geometry and nonassociative algebra. Outstanding examples are {\it gyrogroups} and {\it gyrovector spaces}, and Einstein addition being both {\it gyrocommutative} and {\it gyroassociative}. The prefix "gyro" stems from "gyration", which is the mathematical abstraction of the special relativistic effect known as "Thomas precession".Comment: 78 pages, 26 figure