Rockhopper penguin penguins in different areas. Northern Penguins begin the mating process two months earlier than Southern ones. Two eggs are usually laid a few days apart during early November in hope that at least one will survive, and the second egg is usually larger than the first. They will use the same nest as they did in previous years as well. Eggs hatch about a month later and the mother will have food for the chick. There are currently 19 species and six genera of living penguins. The rockhopper penguin has 3 subspecies: "Eudyptes filholi", the Eastern Rockhopper; "Eudyptes mosleyi", the
Bird vocalization and prevent an energetically costly fight . In birds with song repertoires, individuals may share the same song type and use these song types for more complex communication. Some birds will respond to a shared song type with a song-type match (i.e. with the same song type). This may be an aggressive signal, however results are mixed. Birds may also interact using repertoire-matches, wherein a bird responds with a song type that is in its rival's repertoire but is not the song that it is currently singing. This may be a less aggressive act than song-type matching. Communication through bird