Differences in Fault Bars between Primary Remiges and Rectrices of the Laysan Albatross Phoebastria immutabilis

. Fault bars are narrow structural malformations in feathers. Procellariiform seabirds have long wings that generate lift and power at high speeds and short tails that may not provide dynamic stability. We predicted that Procellariiformes would have fewer fault bars in their wing feathers than in their tail feathers. We examined Laysan Albatrosses Phoebastria immutabilis （ bycatch in the Japanese pelagic longline fishery in the western north Pacific ） and compared the occurrence of fault bars between primary remiges and rectrices using hierarchical Bayesian models. As expected, the models suggested that albatross primary remiges had fewer fault bars than rectrices.