Breeding phenology of African Black Oystercatchers Haematopus moquini on Robben Island, South Africa

The timing of the start and duration of breeding and the effect of these on breeding productivity were analysed for African Black Oystercatchers Haematopus moquini on Robben Island, South Africa, over three breeding seasons from 2001 to 2004. African Black Oystercatchers have a long breeding season, from November to March, enabling a second or sometimes a third nesting attempt after depredation or a natural disaster that destroys nests. The incubation starting date was known or estimated for 205 African Black Oystercatcher clutches over three breeding seasons. Using the estimated starting date of incubation for each nest we found that the 2001/02 and 2002/03 breeding seasons started approximately two weeks earlier than the 2003/04 season and that the 2002/03 breeding season ended approximately one month later than the other two. The late start of the 2003/04 breeding season may be a consequence of greater predation compared to the previous two breeding seasons. The 2003/04 breeding season was the shortest and had the lowest breeding productivity. The 2002/03 breeding season had a lower breeding productivity than 2001/02 because of the loss of a large number of nests during storm surge and spring high tides. The start and duration of the egg-laying period are influenced by predation risk and weather conditions.