GERRITSEN GJ (2001) Post-breeding concentrations of more than 1000 Egyptian Geese Alopochen aegyptiacus in Zwolle. LIMOSA 74 (1): 27-28.

In the province of Overijssel, Egyptian Geese started breeding in 1984, as part of an overall population increase along the river Ijssel, a branch of the Lower Rhine river. Since 1982/83, numbers of Egyptian Geese have been monitored annually through monthly waterbird counts in October-March. These counts cover the most important wetlands in Overijssel. Until 1992/93, numbers did not exceed 100 individuals. Afterwards a sharp increase occurred, reaching a maximum of 600 birds in 1995/96. However, fieldwork in 1997 revealed larger post-breeding gatherings in sand pits around Zwolle in summer. Simultaneous counts to cover these concentrations revealed a population of more than 1000 birds in August 1998 and July 2000 (Tab. 1) These flocks consisted of early breeding birds and their young, as well as non-breeders, most of them in primary moult. Compared to the regular monthly counts in winter, separate censuses to cover post-breeding gatherings might give a better impression of the actual numbers present, as they are more confined to specific areas and therefore more easy to count. An additional national census of Egyptian Geese in July/August is recommended.

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