Seasonal patterns of occurrence of Palaearctic migrants in southern Africa using atlas data

Abstract

A statistical method, using presence/absence data from monthly fieldcards, to describe the phenology of migration is developed. The method uses the generalized linear model to fit a Fourier series to binomial‐type data giving the proportion of fieldcards reporting a species. A method for estimating mid‐arrival and mid‐departure dates, and residency period is also developed. The methodology is applied to data collected during the ‘Southern African Bird Atlas Project’ for the following species: Willow Warbler Phulloscopus trochilus, Red‐backed Shrike Lanius collurio, European Swallow Hirundo rustica, White Stork Ciconia ciconia, Steppe Buzzard Buteo buteo and European Bee‐eater Merops apiaster. Copyright © 1992, Wiley Blackwell. All rights reserved