Breeding of Greater and Lesser Flamingos at Sua Pan, Botswana, 1998–2001

Abstract

Aerial surveys of flamingo breeding colonies were conducted during three consecutive breeding seasons between October 1998 and July 2001, in the south of Sua Pan, Makgadikgadi, Botswana. Rainfall during the rainy seasons of 1998–1999, 1999–2000 and 2000–2001 was 442mm, 851mm and 348mm, respectively, and had a major effect on breeding success of both Lesser and Greater Flamingos. In January 1999, 16 430 pairs of Lesser Flamingos were recorded breeding, but the number of chicks that survived to fledging was unknown owing to the rapid drying of the pan in late March 1999. No Greater Flamingo breeding was seen that season. Exceptional flooding during 1999–2000 produced highly favourable breeding conditions, with numbers of Greater and Lesser Flamingos breeding estimated to be 23 869 and 64 287 pairs, respectively, the highest ever recorded on Sua Pan. Chick survival rate was high and an estimated 18 498 Greater Flamingo chicks and 30 646 Lesser Flamingo chicks fledged. Reduced rainfall in the 2000–2001 wet season resulted in poor breeding conditions, with the total number of adults on the colonies estimated to be 651 pairs of Greater Flamingos and 19 340 pairs of Lesser Flamingos. Rapid drying of the pan in 2000–2001 forced many chicks to walk for over 50km to the last remaining water in the north of the pan, with an estimated 3 000 Lesser Flamingo chicks surviving.