The Telegraph has pictures of the London Zoo’s bird keeper taking a head count of their 40 African penguins and 4 Rockhoppers. Each of them have names but that doesn’t make it any easier, I bet. I’m sure they use a system of descriptions and pictures to sort them all out along with the bands on their wings. I’ve heard (from a web cast) that the Monterey Bay Aquarium makes note of the spots on their Africans’ fronts – their location, size, etc. Anyway, there’s some great pictures of them helping out if you follow the first link above.