Data from: Prebreeding populations and the importance of life history for conserving imperiled seabirds

Seabird conservation often focuses on nestlings and breeding adults. Yet
imperiled seabird populations also contain prebreeders, including
juveniles and subadults, that wait several years before breeding at
colonies. We use previously-published data on reproductive and survival
rates for 90 species to quantify the conservation relevance of prebreeding
seabirds. We find, first, that prebreeders average about half of seabird
populations (median 48.1%, range 7.6–70.0%). Second, while seabird
population growth is much more sensitive to adult survival than prebreeder
survival, human-driven changes may shift the importance of prebreeders for
future population stability. Third, lowering the breeding age is a
potentially useful, but underexplored, route to increasing population
growth. Managing prebreeders could thus play a key role in protecting
seabirds. This task may require answering fundamental questions about the
behavior of young birds. Broadly, we suggest that life history traits
(e.g., breeding age) shape both obstacles to, and opportunities for,
successful conservation.