A team of researchers conducted a unique experiment on Alaskan seabirds, specifically the rhinoceros auklet, to study the effects of increased flight difficulty on survival and reproduction. By attaching small weights to the birds, the scientists made flying more energetically demanding. The results were stark: only 67% of the weighted birds returned from their foraging trips, compared to a much higher return rate for the control group. This significant drop in survival highlights the extreme physical toll that even minor increases in flight effort can have on these seabirds.