Complex sentence: The Dalmatian Pelican is often silent, as most pelicans are, although it can be fairly vocal during the mating season, when it may engage in a wide range of guttural, deep vocalisations, including barks, hisses and grunts.
Split into simpler sentences: The Dalmatian Pelican is often silent, as are most pelicans, although it can be fairly vocal during the mating season. At this time, birds may engage in a wide range of guttural, deep vocalisations including barks, hisses and grunts.