The bailloni clade .28Indian and Pacific oceans.29 Audubon's shearwater

audubon s shearwater puffinus lherminieri bailloni of reunion island.

there appear no significant genetical or morphological differences between these birds, quite amazing given pacific , indian ocean subpopulations must have been isolated long time, , no less 3 unequivocally distinct subspecies (bailloni, persicus , temptator) occur within range of indian ocean dichrous. on other hand, supposed species mascarene shearwater (p. atrodorsalis) inseparable morphologically , genetically bailloni.

clearly, mechanism blocking gene flow @ work, remains unknown – though remarked above, separate breeding seasons seem reasonable assumption , tentatively supported available field data. in addition, entirely mysterious why such mechanism should apply in rather limited , ecologically homogeneous north-western indian ocean range, not in ecologically more diverse , far larger pacific range of dichrous.

these unresolved problems notwithstanding, clade – possibly including preceding 1 – has been proposed constitute separate species, tropical shearwater or baillon s shearwater, puffinus bailloni.