Season of moult of African penguins at Robben Island, South Africa, and its variation, 1988-1998

Counts of African penguins Spheniscus demersus in immature and adult plumag e in the feather-shedding phase of moult were made at Robben island at two- weekly intervals over a 10-year period between 1988 and 1998. For both age- classes, most birds moulted between November and January, although small nu mbers moulted throughout the year. In most years, the peak moult was in lat e November or December. Immature birds had a secondary peak in March. In 19 94/95 for adults, and 1995/96 for immature birds, moult was less synchroniz ed than in other years. This probably resulted from oiling of about 2 400 p enguins in June 1994, following the sinking of the Apollo Sea. Half of thos e birds were cleaned and released. Their subsequent moult may have been ear lier than normal.