Fault bars and the risk of feather damage in cranes

摘要: Fault bars are translucent areas across feathers grown under stressful conditions. They ubiquitous avian species and feather tracts. Because fault weaken structure can lead to breakage, they may reduce flight performance lower fitness. Therefore, natural selection might prime mechanisms aimed at reducing the cost of bars, penalizing their occurrence in those more relevant for flight. Here, we tested one prediction this ‘fault bar allocation hypothesis’: that prevalence, abundance risk damage change wing a long-distance migrant, sandhill crane Grus canadensis as function strength requirements We analysed 2411 with 4676 from 39 cranes active migration. did not increase age. The decreased proximal distal portions, both coverts, according presumed greater external during was variable when producing low ( 2–30%). Altogether, our results suggest common on birds even after millions years evolution because seems penalize particularly harmful certain magnitude, but is unable eliminate less position.