Barham, PeterLudynia, KattaBarham, Barbara2026-06-152026-06-152026Barham, P., Barham, B., Ludynia, K., Parsons, N.J., Mdluli, A., Ngcathu, J.N. and Pichegru, L., 2026. Unusual breeding strategies by African Penguins Spheniscus demersus on Robben Island, South Africa. Ostrich, pp.1-9.https://doi.org/10.2989/00306525.2026.2648851https://hdl.handle.net/10566/24481African Penguins Spheniscus demersus are typically monogamous with biparental care. However, this long-term study on individuals of known identity and sex on Robben Island from 2001 to 2023 revealed several alternative parental care strategies. In rare cases (n = 3, 0.3% of monitored breeding attempts by marked birds), individual penguins were observed incubating eggs and provisioning chicks at two different nests simultaneously. Cooperative breeding occurred in approximately 4% of monitored attempts, where three birds raised chicks at a single nest. In one-third of these cases, all three individuals participated from the incubation stage. Most notably, in 18% of breeding attempts where both pair members were sexed, both individuals were females, suggesting same-sex pairing as a significant reproductive strategy in this population, possibly due to an adult sex-bias ratio in the breeding population.enbigamybreeding trioscooperative breedingfemale–female pairsseabirdsArticle