SEEN - SE European Bird Migration Network
Geographical trends in patterns of arrival and departure of Barn Swallows Hirundo rustica in southern Africa based on bird atlas data

Les G Underhill and Michael Brooks
Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa

Data collection for the Southern African Bird Atlas Project took place from 1987 to 1991. Checklists were submitted throughout the year for 3000 quarter degree grid cells in the six countries of southern Africa: Botswana, Lesotho, Namibia, South Africa, Swaziland and Zimbabwe. For each grid cell, the reporting rate for a species consisted of the percentage of checklists which recorded the species as present. The data for Barn Swallows Hirundo rustica have been split into 10-day periods, and combined across the five years of fieldwork, to produce an animation, based on actual observations, which shows the arrival, stay and departure of Barn Swallows across southern Africa. Alternative graphical displays of the data are also presented. On southward migration, the Barn Swallow arrives earliest in northern Zimbabwe, from early September, and reaches southernmost South Africa about a month later. On northward migration, departure is remarkably synchronous, with (apart from breeding season vagrants) the last records being made in March throughout southern Africa.

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