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The status of the whistling ducks in South Africa

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Clark, A. 1974. The status of the whistling ducks in South Africa. Ostrich 45:1-4. Since the 1920's the status of Dendrocygna viduata and D. bicolor has changed from that of an irregular to that of a regular species in the Transvaal, Zululand, Natal and Orange Free State. In more recent years their numbers have shown a steady increase and breeding has been established. D. viduata numbers built up more quickly than D. bicolor and it has become an established resident whereas D. bicolor is primarily a summer visitor.In the Western Cape Province there has been little change in the status of either species but there are indications that D. viduata is appearing mote regularly in the Eastern Cape Province. The position in East Griqualand and the Transkei is obscure. In South West Africa, excluding the north east corner, D. viduata remains irregular and D. bicolor rare.The preference shown by both species for areas where sewage effluent is disposed of and for new storage dams inevitably links their spread and increase with that of the human population.

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This is the complete set of references for both Volumes 1 and Volume 2 of The Atlas of Southern African Birds
Article
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Article
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Foods of white-faced whistling ducks Dendrocygna viduata were studied relative to sex, age, time of winter and spring, habitat type, and molt intensity in northern KwaZulu-Natal, South Africa, 1995. Adults and juveniles were collected on a naturally occurring pan (Yengweni Pan) and a large water storage dam (Pongolapoort Dam) during early winter (June), late winter (August) and spring (October). While the proportions of individual foods varied throughout the winter and spring and between the two collection sites, there were no sex or age-related dietary differences at either of the sites (P > 0.05). The seeds of moist soil (>99% aggregate dry mass) and aquatic plants (>97%) were the principal dietary items of birds using the Pongolapoort Dam and Yengweni Pan, respectively. While extensive submerged plant communities permit birds to consume large quantities of aquatic seeds on the Yengweni Pan, large fluctuations in water level on the Pongolapoort Dam impede aquatic plant establishment, forcing birds to forage elsewhere. The most commonly consumed seeds contained fat and crude protein levels ranging between 0.82-1.60 and 7.00-12.69%, respectively. Invertebrates were minor dietary items (<1.0%) and although birds tended to consume higher levels of animal matter during the wing-molting period, invertebrate consumption was not correlated with molt intensity. Continued drainage and overgrazing of shallow pans and damming of floodplain systems will adversely affect the aquatic foods used by wintering white-faced whistling ducks, particularly during wing-feather molt. The consequences of large-scale water abstraction schemes and wetland drainage may be even more severe for diving ducks, as they are incapable of foraging in terrestrial habitats.
Article
CLARK, A. 1976. Observations on the breeding of whistling ducks in Southern Africa. Ostrich 41 59–64.Records collected since 1954 show that Dendrocygna viduutu breeds in the Transvaal, Natal and Rhodesia, choosing for the most part a limited mid-summer period when most rains can be expected. D. bicolor records for the Transvaal and Natal show a similar pattern but in Rhodesia breeding is not so restricted. In the Transvaal and Natal most records were obtained near the more populated areas at man-made or artificial breeding grounds. Information is given on nest sites and construction, clutch and brood size, and the behaviour of nesting birds. The percentages of juveniles in flocks of D. viduuta following the breeding season are compared showing the apparent effect of rainfall on breeding success.
Article
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Article
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Article
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