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Journal Article

Breeding data on the birds of Namibia: laying months, colony and clutch sizes and egg measurements

05 Sep 2015-Ornithological Observations-Vol. 6, pp 92-196
TL;DR: The timing of bird breeding in Namibia and the sizes of clutches and nesting colonies are presented per species, derived from 7 231 nest record cards, over 300 publications, museum and private egg collections and via personal communications.
Abstract: The timing of bird breeding in Namibia and the sizes of clutches and nesting colonies are presented per species, derived from 7 231 nest record cards, over 300 publications, museum and private egg collections and via personal communications.

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Journal ArticleDOI
TL;DR: The Raso Lark Alauda razae as mentioned in this paper is a single island endemic confined to the island of Raso in the Cape Verde islands and has been studied via short (11-20 day) similarly-timed visits every year from 2001 to 2017.
Abstract: The Raso Lark Alauda razae is a single island endemic confined to the island of Raso in the Cape Verde islands. It has been studied via short (11–20 day), similarly-timed visits every year from 2001 to 2017. These November/December visits have occurred towards the end of the main rainy period (August–October) in the Cape Verdes. Average clutch size ranged from zero (no nests found) to 3.57 in different years and was strongly correlated with rainfall in the three months preceding the year’s visit, but not with population size, which varied 25-fold during the study period. Since the nomadic pursuit of rain is not an option for the Raso Lark, the species adjusts clutch size according to conditions prevailing on Raso.

10 citations


Cites background from "Breeding data on the birds of Namib..."

  • ...Species in both groups frequently breed during or shortly after the period of rainfall (Brown et al. 2015), although this is not universally true (Ndithia et al....

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  • ...The Raso Lark shows exceptional variation in clutch size, and the largest clutches of five or six exceed those recorded from 18 lark species in Namibia (Brown et al. 2015)....

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Journal ArticleDOI
TL;DR: This work was funded by the University of Pretoria and the National Research Foundation of South Africa and was conducted with the help of a grant from the US National Institutes of Health.
Abstract: NIH GM083863 (to Wayne Getz). Ivan Horak was funded by the University of Pretoria and the National Research Foundation of South Africa.

8 citations


Cites background from "Breeding data on the birds of Namib..."

  • ...Black lines indicate administrative regions of Namibia, gray polygons are government protected areas. took place from March 2008-August 2010, jackals from January 2009-June 2011, elephants from October 2008-July 2010 (sampling in dry seasons only), and springbok from August 2009-April 2010....

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  • ...Vulture courtship commences in April; egg laying occurs between April and August (Brown et al., 2015) and banding of chicks in the nest took place in September-November....

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Journal ArticleDOI
01 Mar 2019-Ostrich
TL;DR: In an extensive literature search, a total of 16 raptor species were recorded as nesting on top of large weaver nests as discussed by the authors, including Red-billed Buffalo-Weaver Bubalornis niger and 25.7% of Sociable Weaver Philetairus socius nests.
Abstract: Several raptor species nest on top of large weaver nests. These weaver nests are usually sited in trees, but 11.7% of Red-billed Buffalo-Weaver Bubalornis niger and 25.7% of Sociable Weaver Philetairus socius nests occur on man-made structures. In an extensive literature search, a total of 16 raptor species were recorded as nesting on top of weaver nests. At least 10 raptor species used weaver nests built in trees. Seven raptor species used weaver nests on man-made sites and four raptor species only used weaver nests built on man-made sites. No owls have been recorded as using weaver nests on man-made sites. There are historical records of raptors nesting on top of weaver nests in trees, while nesting on top of weaver nests sited on man-made structures appears to be a more recent adaptation. Costs and benefits of nesting on man-made sites are briefly listed. Nesting on man-made sites may increase (by both weavers and raptors) and raptor researchers are encouraged to document cases of raptors nesting on we...

6 citations

Journal Article
TL;DR: In Africa, human populations have expanded and urbanized across the continent, creating an abundance of myna habitat, and, perhaps more importantly, creating a network of habitat corridors through the building of roads and towns along those roads as discussed by the authors.
Abstract: It will be fascinating to monitor their spread, which will no doubt continue, across Africa. Human populations have expanded and urbanized across the continent, creating an abundance of myna habitat, and, perhaps more importantly, creating a network of habitat corridors through the building of roads and towns along those roads.

3 citations

References
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Book
01 Jan 1983

2,320 citations


"Breeding data on the birds of Namib..." refers background in this paper

  • ...The birth of small mammals (Smithers 1983, Apps 2000) coincides with the latter half of the period of low vegetation cover and extends into the late summer, from October to March (Figure 47 good rainfall years small mammals can breed prolifically, raising multiple litters, resulting in rapid…...

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  • ...There are few studies on the breeding season of medium-sized mammals in Namibia and information was drawn from the nearest studies in general reference works for southern Africa (Smithers 1983, Apps 2000)....

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Journal ArticleDOI
TL;DR: Relationship between the sexes dispersion breeding density winter density problems concerning nest-sites breeding strategies breeding rates behaviour in the breeding season fidelity to breeding areas movements mortality human persecution DDT and other organo-chlorines other pollutants and pesticides conservation management breeding from captive birds scientific names of raptors.
Abstract: Relationship between the sexes dispersion breeding density winter density problems concerning nest-sites breeding strategies breeding rates behaviour in the breeding season fidelity to breeding areas movements mortality human persecution DDT and other organo-chlorines other pollutants and pesticides conservation management breeding from captive birds scientific names of raptors.

2,115 citations


"Breeding data on the birds of Namib..." refers background in this paper

  • ...Sep Oct Nov Dec - Ornithological Observations, Vol 6: 92-196 Birds of prey Like most birds, birds of prey, including owls, breed during the time of year when food is most readily available (Newton 1979)....

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  • ...Birds of prey Like most birds, birds of prey, including owls, breed during the time of year when food is most readily available (Newton 1979)....

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Journal ArticleDOI
03 Apr 2008-Ibis
TL;DR: There is a strong tendency for those young which are hatched earliest in the season to have the greatest chance of surviving to breed, and not all species are likely to be prevented, by food shortage, from breeding at the best time for raising young.
Abstract: Summary Examination of survival rdtes of nestlings and fledglings of some species show that there is a strong tendency for those young which are hatched earliest in the season to have the greatest chance of surviving to breed. Since natural selection so strongly favours parents who leave many surviving young, the question arises as to why other birds breed later than the date at which they could most successfully raise their young. It is suggested that the food supply for the breeding females immediately prior to the breeding season may limit their ability to form eggs and the females may thus not be able to lay at the time which would result in young being in the nest at the best time for raising them, but as soon after this time as the female is able to produce her eggs. Not all species are likely to be prevented, by food shortage, from breeding at the best time for raising young and the groups of birds most likely to be affected are discussed.

1,364 citations


"Breeding data on the birds of Namib..." refers background in this paper

  • ...provisioning of nestlings and the independence stage of young birds) being synchronized with optimum food availability, is the suggestion that the food supply for breeding females immediately prior to the breeding season may limit their ability to form eggs (Perrins 1970)....

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  • ...…reproductive cycle (e.g. provisioning of nestlings and the independence stage of young birds) being synchronized with optimum food availability, is the suggestion that the food supply for breeding females immediately prior to the breeding season may limit their ability to form eggs (Perrins 1970)....

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Journal ArticleDOI
TL;DR: It is concluded that late pairs are constrained from producing a clutch earlier in the season, presumably by the fitness costs this would entail, and evidence for the date hypothesis leads us to conclude that quality is important for the ability to breed early.
Abstract: Reproductive success usually declines in the course of the season, which may be a direct effect of breeding time, an effect of quality (individuals with high phenotypic or environmental quality breeding early), or a combination of the two. Being able to distinguish between these possibilities is crucial when trying to understand individual variation in annual routines, for instance when to breed, moult and migrate. We review experiments with free-living birds performed to distinguish between the ‘timing’ and ‘quality’ hypothesis. ‘Clean’ manipulation of breeding time seems impossible, and we therefore discuss strong and weak points of different manipulation techniques. We find that the qualitative results were independent of manipulation technique (inducing replacement clutches versus cross-fostering early and late clutches). Given that the two techniques differ strongly in demands made on the birds, this suggests that potential experimental biases are limited. Overall, the evidence indicated that date and quality are both important, depending on fitness component and species, although evidence for the date hypothesis was found more frequently. We expected both effects to be prevalent, since only if date per se is important, does an incentive exist for high-quality birds to breed early. We discuss mechanisms mediating the seasonal decline in reproductive success, and distinguish between effects of absolute date and relative date, for instance timing relative to seasonal environmental fluctuations or conspecifics. The latter is important at least in some cases, suggesting that the optimal breeding time may be frequency dependent, but this has been little studied. A recurring pattern among cross-fostering studies was that delay experiments provided evidence for the quality hypothesis, while advance experiments provided evidence for the date hypothesis. This indicates that late pairs are constrained from producing a clutch earlier in the season, presumably by the fitness costs this would entail. This provides us with a paradox: evidence for the date hypothesis leads us to conclude that quality is important for the ability to breed early.

510 citations

Journal ArticleDOI
03 Apr 2008-Ibis
TL;DR: Proximate factors provide a physiological timing mechanism whereby the gonads recrudesce, and eggs are laid, at such a time that, on the average, the young hatch at a season when there is sufficient food to raise them.
Abstract: Summary. 1 In northern Europe, the northward movement of the sun in spring has so extensive an influence, that the food of all species of birds reaches its maximum at some time between late spring and early autumn. As a result, and in contrast to the tropics, nearly all species of birds lay their eggs in roughly the same period of the year. 2 A review of the breeding seasons of British birds reveals some interesting correlations between time of breeding and time of maximum food, and also many apparent puzzles, particularly as regards the marked differences in breeding season sometimes found between related species. 3 In Lapland, all species start breeding 1–2 months later than in Britain, and the breeding season is much less extended. As compared with Britain, the Corvidae and predatory birds of Lapland lay early relative to the small passerines, but among the small passerines, and also among the predators, the different species tend to breed in the same order relative to each other as they do in Britain. 4 Quantitative measurement of breeding seasons is much needed, and some examples showing the advantages of this method are given in Tables 1–3 and text-Figs. 1–5. 5 It is considered that, through the action of natural selection, the breeding season of each species coincides with the time of year when offspring can be raised with greatest success. The major ultimate factor involved is, therefore, the food for the young birds (and hence the factors which determine the abundance and availability of this food). But there may be modifying ultimate factors concerned with the survival of the parents, of the nest and eggs, and of the juvenile birds in the period soon after they leave the nest. 6 Proximate factors provide a physiological timing mechanism whereby the gonads recrudesce, and eggs are laid, at such a time that, on the average, the young hatch at a season when there is sufficient food to raise them. In European birds, daylength seems the major proximate factor, but there are several modifying factors, perhaps including temperature.

213 citations


"Breeding data on the birds of Namib..." refers background in this paper

  • ...…species breed at the time of year that is most profitable to them and their offspring, the dates and duration vary considerably between different ecological groups of birds depending on many factors including regional climatic conditio habitat and diet (Lack 1950, Immelmann 1972, Maclean 1990)....

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