TL;DR: Thompson et al. as discussed by the authors described the demography and breeding patterns of the Redbilled Quelea in eastern Kenya with respect to abnormally high rainfall in Tsavo-East National Park during late 1984 and early 1985.
Abstract: Summary Thompson, J.J. 1993. Opportunistic breeding by the Redbilled Quelea in eastern Kenya. Ostrich 64: 32–37. The demography and breeding patterns of the Redbilled Quelea in eastern Kenya are described with respect to abnormally high rainfall in Tsavo-East National Park during late 1984 and early 1985. The prolonged breeding that occurred, together with the early sexual maturation of young queleas and their entry into the breeding population, underlined the opportunistic nature of quelea migration and breeding strategies. Opportunism may be considered to be the most adaptive breeding strategy for queleas generally, but may be more conspicuous in East Africa than in some other parts of Africa because of more complex rainfall patterns.
TL;DR: The large differences in timing and duration of moult in this study only support the short-distance ‘rainfall-migration’ model for Red-billed Queleas in southern Africa.
Abstract: The onset and duration of primary moult were investigated for adult Red-billed Queleas (Quelea quelea) in southern Africa. The duration of moult was shortest in Namibia (75 days), intermediate in Botswana (83 days) and longest in Gauteng Province (101 days) and the Eastern Cape (124 days), South Africa. The timing of the onset of moult was similar in Namibia and Botswana (21 and 31 May respectively), but considerably earlier in the Eastern Cape and Gauteng Province (6 and 23 April respectively). Completion of primary moult was well synchronised, ending in August in all sub-regions. Production of feather mass was uniform and speed of moult was controlled by the rate of growth of individual primaries. When moult was faster, fewer feathers grew simultaneously, possibly to reduce the aerodynamic effect of the wing-gap. Red-billed Queleas are thought to migrate relative to the movement of rain fronts, allowing possible multiple breeding events in one season. In southern Africa, Queleas are present throughout their range all year, and a proportion of the population moves short distances in apparently random directions. The large differences in timing and duration of moult in this study only support the short-distance ‘rainfall-migration’ model.
TL;DR: Proposed methods for estimating the hatching dates of free-flying juvenile Red-billed Queleas, Quelea quelea, and hence establishing their likely geographical origins and patterns of post-natal dispersal are evaluated.
Abstract: This paper evaluates potential methods for estimating the hatching dates of free-flying juvenile Red-billed Queleas, Quelea quelea, and hence establishing their likely geographical origins and patterns of post-natal dispersal. Based on studies of captive juveniles, the progress of the post-juvenile moult can discriminate up to three differently aged cohorts of young in the same population. Bill colour can help to differentiate very young birds from older ones before post-juvenile moult begins. Skull pneumatization is not useful for precise ageing; it proceeds significantly more slowly in moles than females and may not be complete by one year of age. Iris colour remains to be properly evaluated as an ageing criterion. Collections from the Okavango region of northwestern Botswana indicated that juvenile Red-billed Queleas started to arrive there as the local breeding season began. Such birds could only have originated outside Botswana in colonies established in regions of earlier rainfall, probably in those...