R. J. Nuttall

Abstract: Summary Nuttall, R.J. 1993. Seasonal changes in the birdlife of a pen-urban grassland community. Ostrich 64: 1–7. Visits to a grassland habitat near Pietermaritzburg, Natal, South Africa were undertaken over a period of ten months (March-December) to document changes in avifauna, and to investigate possible reasons for any changes. A total of 72 bird species was recorded. Monthly species totals showed considerable fluctuation, with species diversity highest in spring-early summer (n=53) and lowest in winter (n=14). Terrestrial insectivores were the best represented fin terms of number of species) during the course of the study. The influence of rainfall on food availability and on vegetation is considered important in determining the structure of this avian community. Observations of the assumption (and loss) of nuptial plumage in euplectines showed that Longtailed Widows Euplectes progne developed breeding plumage earliest, and retained it for the longest period of time. Both Whitewinged E. albonotatus a...

Abstract: Summary Nuttall, R.J. 1992. Breeding biology and behaviour of the Quail Finch Ortygospiza atricollis. Ostrich 63:110-117. During a study of the breeding biology of the Quail Finch Ortygospiza atricollis, observations of nest-building, egg-laying, incubation and nestling periods, and nestling development in a grassland near Pietermaritzburg, South Africa were supplemented with observations of breeding behaviour in captivity. Mean clutch size was 4,5 and eggs were laid at intervals of approximately one day. Incubation began after the third or fourth egg was laid. An incubation period of 15–16 days and an estimated nestling period of 18–19 days was recorded. Incubation and brooding are shared by both sexes. Breeding success was low (26,7% −28,6%), with most losses resulting from predation during either the egg-laying or incubation stages.

Abstract: The brood-parasitic indigobirds Vidua spp. mimic the songs of their foster species, which for many species of indigobirds are Lagonosticta firefinches. We report additional associations of indigobirds with estrildid finches in west Africa. Quail-finch Indigobirds Vidua nigeriae in northern Cameroon mimic the songs of Quail-finch Ortygospiza atricollis. Gold-breast Indigobirds Vidua raricola in Cameroon and Sierra Leone mimic the songs of Gold-breast Amandava subflava. Both indigobirds are distinct in male breeding plumage from other indigobirds. Also, a population of blue indigobirds Vidua sp. in Cameroon mimics the songs of Brown Twinspot Clytospiza monteiri. They are similar in colour and size to blue indigobirds associated with Dark Firefinch L. rubricata and Black-bellied Firefinch L. rara. Mouth patterns of fledged young Quail-finch Indigobirds and Goldbreast Indigobirds resemble those of their song-model and presumed foster species, but the mouth pattern of a fledged young associated with the Brown Twinspot mimic was not distinct from the mouth of young Black-bellied Firefinch. The field observations show associations of certain species of indigobirds with finches other than the firefinches. The results are consistent with mitochondrial DNA estimates of greater genetic similarity among indigobirds than among their foster species. The field observations support the hypothesis of evolutionary associations of the brood parasite and foster species by colonization with switching from one foster to another rather than by cospeciation.

Abstract: Considering the frequent nature of fires and resultant drastic change in habitat following fire, research on the effects of fire on birds in the grasslands of South Africa is surprisingly scarce. For at least five months after burns we followed the changes in bird species composition, species richness and densities of two controlled burns and one accidental fire at the Barberspan Nature Reserve in grasslands that had not been burned or grazed in 10 years. Compared with the control areas, species richness and densities increased in the burned areas immediately following the burns, with more species and birds recruited to the burned areas than were lost. Immediate post-burn opportunists tended to be larger species, and the biomass increase mirrored the increases in species richness and densities in burned areas. Avian species richness, densities and biomass tended to return to the initial conditions after a number of months. Although the bird communities from two controlled-burns differed before the burns, they converged to a characteristic immediate post-burn composition. Five months after the burns however, the bird communities reflected a pre-burn composition. Indications were that birds in an area larger than that burned were affected. Mosaic burning, with shifting large and small patches, should be considered on a landscape scale. Ostrich 2007, 78(3): 591–608

Abstract: The grassland biome in South Africa has a summer rainfall and Southern Red Bishops Euplectes orix , Fan-tailed Widows E. axillaris , White-winged Widow E. albonotatus , Red-collared Widow E. ardens and Long-tailed Widow E. progne breed from October or November to March. Primary moult starts in late March or early April. The widows with long tails (Long-tailed and Red-collared Widows) have moult durations of two months, while the widows with shorter tails (White-winged and Fan-tailed Widows) had moult durations of 1.5–1.7 months. Moult ends in late May or early June. Long-tailed Widows have rounder wings than other weaver species, possibly because their larger size affects flight aerodynamics. In the winter rainfall region, Southern Red Bishops and Yellow Bishops E. capensis start breeding after the winter rains, from August–November, and moult starts in early December. Primary moult duration in Yellow Bishops is relatively long, at 3.4 months. Yellow Bishops grow individual primary feathers at an average rate of 21.3 days per feather, while the other species moult primaries more quickly: White-winged Widow 8.1 days, Fan-tailed Widow 11.3 days, and Red-collared Widow 14.4 days. The number of primaries growing simultaneously is similar in the different species. The longer duration of primary moult of the Yellow Bishop may be related to food. Ostrich 2006, 77(3&4): 142–152

Abstract: Summary Nuttall, R.J. 1993. Vocal behaviour of the Quail Finch Ortygospiza atricollis. Ostrich 64:97-104. Vocalizations (contact, take-off, flight, alarm, beckon, nestling begging and nestling threat calls, contact phrases and song of the Quail Finch Ortygospiza atricollis are described from observations and recordings of wild-caught aviary birds, and from individuals in the field. The predominantly terrestrial habits and grassland habitat of this species ma have been important in the evolution of a specialized vocal repertoire, particularly of sex-specific vocalizations necessary for sexual and individual recognition, and the maintenance of contact between individuals.