Current name: African Penguin. Between the late 1970s and the mid 1980s there were large decreases in numbers of jackass penguins Spheniscus demersus breeding near the centre of the species' distribution, whereas near the periphery of its breeding range numbers either decreased less severely or remained stable. Similar trends had been observed between the mid 1950s and the late 1970s, with the exception that at some peripheral localities numbers had been increasing.