Ardea
Official journal of the Netherlands Ornithologists' Union

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Broekhuysen G.J. & Brown A.R. (1963) The moulting pattern of European Swallows, Hirundo rustica, wintering in the surroundings of Cape Town, South Africa. ARDEA 51 (1): 25-43
1) Observations on the different age classes of European Swallows 'wintering' in the neighbourhood of Cape Town show that a high percentage of the Swallows arriving in November are birds which are two or more years old. Large numbers of birds of the year, presumably immature arrive somewhat later. By January when all birds have arrived, these young birds are in the majority. 2) During their stay in the wintering quarters the Swallows undergo a complete moult which is a gradual process and spread over several months. Full details of the moulting pattern and its progress for the different parts of the body are given. 3) The overall moult in older birds 'wintering' around Cape Town does not show a convincing difference with birds of the year which have arrived later. 4) It is shown that by the time the Swallows depart for their journey north, a considerable number have not fully completed the moulting process yet. 5) The moulting pattern of Cape Town birds is compared with birds wintering in the Congo. It was found that on the whole Congo birds were more advanced in their moult than Cape Town birds at the same periods of their stay. 6) The weight of wintering birds is compared for the different months of their stay. Some significant difference was found. Apparently no spectacular increase in weight prior to departure occurs. The importance of this lack of reserves in connection with the sensitivity to adverse climatical conditions encountered during migration is stressed.


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