Individual study: Successful rehabilitation and relocation of African penguins Spheniscus demersus following oil spills in South Africa
Wolfaardt A.C. & Nel D.C. (2003) Breeding productivity and annual cycle of rehabilitated African penguins following oiling. Pages 18-24 in: D.C. Nel & P.A. Whittington (eds.) Rehabilitation of oiled African Penguins: a conservation success story. BirdLife South Africa and Avian Demography Unit, Cape Town.
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Relocate birds following oil spills
A replicated trial following the Treasure oil spill in 2000 between Robben and Dassen Islands, Western Cape, South Africa (Wolfaardt & Nel 2003), found that 62% of 1,130 African penguins Spheniscus demersus that were moved 800 km east and released were recorded on Dassen Island, two years after the event, with 41% breeding. This compared with a higher number of rehabilitated (oiled, cleaned and released) birds being seen (75% of 2,744), but fewer breeding (17%). Relocated birds began arriving at Dassen Island 11 days after being released, with most arriving 18 days or so after relocation. In total, 19,500 birds were relocated. This study is also discussed in ‘Clean birds following oil spills’.
Clean birds following oil spills
A replicated, controlled study on Dassen Island, Western Cape, South Africa (Wolfaardt & Nel 2003), found that at least 60% of African penguins Spheniscus demersus that were rehabilitated following the 1994 Apollo Sea oil spill had bred within six years of the spill. Productivity of these birds was no different from un-oiled birds (0.32 chicks/egg for 599 oiled birds vs. 0.30 for 558 un-oiled) and their chicks showed identical growth patterns. However, the authors note that during some periods of stress, the rehabilitated birds had significantly lower productivity than un-oiled birds. Of 2,744 birds rehabilitated after the Treasure spill in 2000, 75% were seen two years later, but only 17% had bred. Rehabilitated birds were more likely than controls to change breeding partners (67% keeping mates vs. 80-94%), but this difference appeared to be temporary. This study is also discussed in ‘Relocate birds away from oil spills’.