Complex sentence: Around 22% of Dark-mantled Sooties survive until adulthood (there are no figures for Light-mantled), both species return to the breeding colony after 7-10 years of fledging, and begin to breed a few years later.
Split into simpler sentences: Around 22% of Dark-mantled Sooties survive until adulthood (there are no figures for Light-mantled). Both species return to the breeding colony after 7-10 years of fledging, and begin to breed a few years later.