Editor’s note: Seabirds are among the indicator species that provide rich insight into the health of their ecosystems. This week we share an edited excerpt from Eric Wagner’s new book, “Seabirds as Sentinels: Auklets, Puffins, Shearwaters, and the View from Destruction Island” (University of Washington Press, March 10), in which Wagner follows a team of scientists as they seek to understand how climate change is affecting our region.