Influence of moult and location on patterns of daily movement by Egyptian Geese in South Africa

Abstract

The daily movements of 18 Egyptian Geese (Alopochen aegyptiaca) in South Africa were recorded using satellite telemetry. General additive mixed models were used to explain the distances moved by the birds at different times of the day, correcting for sex, site, season and individual. Distances moved by birds in the mesic, winter-rainfall, south-western region (Strandfontein) of South Africa were compared with movements in the semi-arid, summer-rainfall region (Barber-span) of northern South Africa. Moulting birds all remained at single wetlands during moult, displayed crepuscular patterns of activity and nocturnal retreats to safety. At the end of moult, birds dispersed away from moulting sites. The longest daily distances travelled by individuals took place mainly just before moult was due to start or within the first 10 days after completing moult, providing strong evidence that Egyptian Geese undertake moult migrations. The daily pattern of movement was strongly skewed, with >70% of flights being short (<10 km) and longer flights mainly occurring at night (88%). There were considerable differences in patterns of dispersal between birds at the summer-rainfall site and the winter-rainfall one. Summer-rainfall birds undertook long-distance movements between wetlands whereas Winter-rainfall birds appeared to move randomly and over short distances.

Additional keywords:

• Afrotropical region
• telemetry
• waterfowl